ubifs: possible circular locking dependency

DISCUSSION Marc Kleine-Budde 2 participants 11 messages Feb 6, 2013 – Feb 20, 2013

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VFS Memory technology devices (MTD) SELinux security module

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Marc Kleine-Budde

author

2013-02-06 11:20 UTC #0 lore raw

Hello,

I'm on a arm imx28 v3.8-rc6 (+ a handfull of patches to support the custom board) but no modifications on ubifs, selinux or the vfs layer. And not including the xattr patches by Subodh Nijsure.

When booting with SELinux and lockdep enabled I see this circular locking dependency:

[    5.390312] ======================================================
[    5.396500] [ INFO: possible circular locking dependency detected ]
[    5.402781] 3.8.0-rc6-00005-g4f7e39d #49 Not tainted
[    5.407750] -------------------------------------------------------
[    5.414031] systemd/1 is trying to acquire lock:
[    5.418656]  (&c->tnc_mutex){+.+...}, at: [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.426343]
[    5.426343] but task is already holding lock:
[    5.432218]  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.440375]
[    5.440375] which lock already depends on the new lock.
[    5.440375]
[    5.448593]
[    5.448593] the existing dependency chain (in reverse order) is:
[    5.456093]
-> #4 (&isec->lock){+.+.+.}:
[    5.460250]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.465437]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.471125]        [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.477437]        [<c0189bd8>] security_d_instantiate+0x1c/0x34
[    5.483500]        [<c017a614>] debugfs_mknod.part.15.constprop.18+0x94/0x128
[    5.490656]        [<c017a858>] __create_file+0x1b0/0x25c
[    5.496093]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.501781]        [<c0491ce8>] pinctrl_init+0x1c/0xd0
[    5.506968]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.512593]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.518562]        [<c034f398>] kernel_init+0x8/0xe4
[    5.523562]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.528812]
-> #3 (&sb->s_type->i_mutex_key#2){+.+.+.}:
[    5.534312]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.539468]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.545187]        [<c017a6f8>] __create_file+0x50/0x25c
[    5.550531]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.556218]        [<c026cfc4>] clk_debug_create_subtree+0x1c/0x108
[    5.562500]        [<c0495bfc>] clk_debug_init+0x68/0xc0
[    5.567875]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.573468]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.579437]        [<c034f398>] kernel_init+0x8/0xe4
[    5.584437]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.589687]
-> #2 (prepare_lock){+.+.+.}:
[    5.593937]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.599125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.604812]        [<c026d400>] clk_prepare+0x18/0x38
[    5.609906]        [<c023a2f8>] __gpmi_enable_clk+0x30/0xb0
[    5.615531]        [<c023a7bc>] gpmi_begin+0x18/0x530
[    5.620625]        [<c0239244>] gpmi_select_chip+0x3c/0x54
[    5.626156]        [<c02341ac>] nand_do_read_ops+0x7c/0x3e4
[    5.631750]        [<c023483c>] nand_read+0x50/0x74
[    5.636656]        [<c02198e4>] part_read+0x5c/0xa4
[    5.641593]        [<c0217404>] mtd_read+0x84/0xb8
[    5.646406]        [<c02450cc>] ubi_io_read+0xa0/0x2c0
[    5.651593]        [<c0242640>] ubi_eba_read_leb+0x190/0x424
[    5.657281]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.662562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.667906]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.673437]        [<c014e780>] ubifs_read_sb_node+0x54/0x78
[    5.679125]        [<c014f444>] ubifs_read_superblock+0xc60/0x163c
[    5.685343]        [<c014d64c>] ubifs_mount+0x800/0x171c
[    5.690687]        [<c00b5740>] mount_fs+0x44/0x184
[    5.695593]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.700968]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.705968]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.710875]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.716562]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.722281]        [<c034f398>] kernel_init+0x8/0xe4
[    5.727281]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.732531]
-> #1 (&le->mutex){++++..}:
[    5.736625]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.741812]        [<c0356468>] down_read+0x40/0x54
[    5.746718]        [<c02424e4>] ubi_eba_read_leb+0x34/0x424
[    5.752312]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.757562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.762937]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.768437]        [<c016edc0>] ubifs_load_znode+0x88/0x560
[    5.774062]        [<c0155254>] ubifs_lookup_level0+0x190/0x1dc
[    5.780031]        [<c01552e4>] ubifs_tnc_locate+0x44/0x198
[    5.785656]        [<c014c614>] ubifs_iget+0x6c/0x8a4
[    5.790718]        [<c014da64>] ubifs_mount+0xc18/0x171c
[    5.796093]        [<c00b5740>] mount_fs+0x44/0x184
[    5.801000]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.806343]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.811343]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.816250]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.821968]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.827656]        [<c034f398>] kernel_init+0x8/0xe4
[    5.832656]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.837906]
-> #0 (&c->tnc_mutex){+.+...}:
[    5.842250]        [<c004de48>] __lock_acquire+0x14ec/0x1b08
[    5.847968]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.853125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.858812]        [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.864437]        [<c0155a48>] ubifs_tnc_lookup_nm+0x28/0x150
[    5.870312]        [<c016fc18>] ubifs_getxattr+0xc0/0x254
[    5.875750]        [<c018e468>] inode_doinit_with_dentry+0x25c/0x55c
[    5.882125]        [<c018f1a8>] sb_finish_set_opts+0xa4/0x21c
[    5.887906]        [<c019055c>] selinux_set_mnt_opts+0x2ec/0x4b8
[    5.893968]        [<c01907dc>] superblock_doinit+0xb4/0xc0
[    5.899562]        [<c00b51f4>] iterate_supers+0xb4/0xdc
[    5.904906]        [<c01a02e8>] security_load_policy+0x248/0x3c4
[    5.910968]        [<c0194994>] sel_write_load+0x9c/0x6a0
[    5.916406]        [<c00b2148>] vfs_write+0xa0/0x17c
[    5.921406]        [<c00b2450>] sys_write+0x3c/0x70
[    5.926343]        [<c00093a0>] ret_fast_syscall+0x0/0x38
[    5.931781]
[    5.931781] other info that might help us debug this:
[    5.931781]
[    5.939781] Chain exists of:
  &c->tnc_mutex --> &sb->s_type->i_mutex_key#2 --> &isec->lock
[    5.948500]  Possible unsafe locking scenario:
[    5.948500]
[    5.954437]        CPU0                    CPU1
[    5.958968]        ----                    ----
[    5.963500]   lock(&isec->lock);
[    5.966781]                                lock(&sb->s_type->i_mutex_key#2);
[    5.973843]                                lock(&isec->lock);
[    5.979625]   lock(&c->tnc_mutex);
[    5.983062]
[    5.983062]  *** DEADLOCK ***
[    5.983062]
[    5.989000] 4 locks held by systemd/1:
[    5.992781]  #0:  (sel_mutex){+.+.+.}, at: [<c0194918>] sel_write_load+0x20/0x6a0
[    6.000343]  #1:  (&type->s_umount_key#26){.+.+..}, at: [<c00b51d0>] iterate_supers+0x90/0xdc
[    6.008968]  #2:  (&sbsec->lock){+.+.+.}, at: [<c01902d4>] selinux_set_mnt_opts+0x64/0x4b8
[    6.017343]  #3:  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    6.025937]
[    6.025937] stack backtrace:
[    6.030375] [<c000d0f0>] (unwind_backtrace+0x0/0xf0) from [<c0351a2c>] (print_circular_bug+0x25c/0x2a8)
[    6.039843] [<c0351a2c>] (print_circular_bug+0x25c/0x2a8) from [<c004de48>] (__lock_acquire+0x14ec/0x1b08)
[    6.049531] [<c004de48>] (__lock_acquire+0x14ec/0x1b08) from [<c004e8e8>] (lock_acquire+0x64/0x78)
[    6.058531] [<c004e8e8>] (lock_acquire+0x64/0x78) from [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec)
[    6.067531] [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec) from [<c01552d0>] (ubifs_tnc_locate+0x30/0x198)
[    6.076968] [<c01552d0>] (ubifs_tnc_locate+0x30/0x198) from [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150)
[    6.086593] [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150) from [<c016fc18>] (ubifs_getxattr+0xc0/0x254)
[    6.096031] [<c016fc18>] (ubifs_getxattr+0xc0/0x254) from [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c)
[    6.105968] [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c) from [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c)
[    6.116281] [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c) from [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8)
[    6.126218] [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8) from [<c01907dc>] (superblock_doinit+0xb4/0xc0)
[    6.136000] [<c01907dc>] (superblock_doinit+0xb4/0xc0) from [<c00b51f4>] (iterate_supers+0xb4/0xdc)
[    6.145093] [<c00b51f4>] (iterate_supers+0xb4/0xdc) from [<c01a02e8>] (security_load_policy+0x248/0x3c4)
[    6.154625] [<c01a02e8>] (security_load_policy+0x248/0x3c4) from [<c0194994>] (sel_write_load+0x9c/0x6a0)
[    6.164218] [<c0194994>] (sel_write_load+0x9c/0x6a0) from [<c00b2148>] (vfs_write+0xa0/0x17c)
[    6.172781] [<c00b2148>] (vfs_write+0xa0/0x17c) from [<c00b2450>] (sys_write+0x3c/0x70)
[    6.180843] [<c00b2450>] (sys_write+0x3c/0x70) from [<c00093a0>] (ret_fast_syscall+0x0/0x38)

Any hints how to solve the problem?

Marc

Signature · 4 lines

Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

Marc Kleine-Budde

author

2013-02-08 14:11 UTC #1 lore raw

SELinux + ubifs: possible circular locking dependency

Hello,

I'm on a arm imx28 v3.8-rc6 (+ a handfull of patches to support the custom board) but no modifications on ubifs, selinux or the vfs layer. And not including the xattr patches by Subodh Nijsure.

When booting with SELinux and lockdep enabled I see this _possible_ circular locking dependency:

This warning shows up every boot, but not again later. Is lockep automatically disabled after the first circular lockdep warning?

This particular situation, where the dependency chain is occurs as far as I understand only at boot. Three functions in this chain are only called once:
- pinctrl_init()
- clk_debug_init()
- mount_block_root()

Another critical ingredient is security_load_policy().

Is this really an uncritical catch of the lock validator? If so, is it possible to annotate this, so that the system boot up quietly?

Quoted 139 lines

[    5.390312] ======================================================
[    5.396500] [ INFO: possible circular locking dependency detected ]
[    5.402781] 3.8.0-rc6-00005-g4f7e39d #49 Not tainted
[    5.407750] -------------------------------------------------------
[    5.414031] systemd/1 is trying to acquire lock:
[    5.418656]  (&c->tnc_mutex){+.+...}, at: [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.426343]
[    5.426343] but task is already holding lock:
[    5.432218]  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.440375]
[    5.440375] which lock already depends on the new lock.
[    5.440375]
[    5.448593]
[    5.448593] the existing dependency chain (in reverse order) is:
[    5.456093]
-> #4 (&isec->lock){+.+.+.}:
[    5.460250]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.465437]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.471125]        [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.477437]        [<c0189bd8>] security_d_instantiate+0x1c/0x34
[    5.483500]        [<c017a614>] debugfs_mknod.part.15.constprop.18+0x94/0x128
[    5.490656]        [<c017a858>] __create_file+0x1b0/0x25c
[    5.496093]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.501781]        [<c0491ce8>] pinctrl_init+0x1c/0xd0
[    5.506968]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.512593]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.518562]        [<c034f398>] kernel_init+0x8/0xe4
[    5.523562]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.528812]
-> #3 (&sb->s_type->i_mutex_key#2){+.+.+.}:
[    5.534312]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.539468]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.545187]        [<c017a6f8>] __create_file+0x50/0x25c
[    5.550531]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.556218]        [<c026cfc4>] clk_debug_create_subtree+0x1c/0x108
[    5.562500]        [<c0495bfc>] clk_debug_init+0x68/0xc0
[    5.567875]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.573468]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.579437]        [<c034f398>] kernel_init+0x8/0xe4
[    5.584437]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.589687]
-> #2 (prepare_lock){+.+.+.}:
[    5.593937]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.599125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.604812]        [<c026d400>] clk_prepare+0x18/0x38
[    5.609906]        [<c023a2f8>] __gpmi_enable_clk+0x30/0xb0
[    5.615531]        [<c023a7bc>] gpmi_begin+0x18/0x530
[    5.620625]        [<c0239244>] gpmi_select_chip+0x3c/0x54
[    5.626156]        [<c02341ac>] nand_do_read_ops+0x7c/0x3e4
[    5.631750]        [<c023483c>] nand_read+0x50/0x74
[    5.636656]        [<c02198e4>] part_read+0x5c/0xa4
[    5.641593]        [<c0217404>] mtd_read+0x84/0xb8
[    5.646406]        [<c02450cc>] ubi_io_read+0xa0/0x2c0
[    5.651593]        [<c0242640>] ubi_eba_read_leb+0x190/0x424
[    5.657281]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.662562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.667906]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.673437]        [<c014e780>] ubifs_read_sb_node+0x54/0x78
[    5.679125]        [<c014f444>] ubifs_read_superblock+0xc60/0x163c
[    5.685343]        [<c014d64c>] ubifs_mount+0x800/0x171c
[    5.690687]        [<c00b5740>] mount_fs+0x44/0x184
[    5.695593]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.700968]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.705968]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.710875]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.716562]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.722281]        [<c034f398>] kernel_init+0x8/0xe4
[    5.727281]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.732531]
-> #1 (&le->mutex){++++..}:
[    5.736625]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.741812]        [<c0356468>] down_read+0x40/0x54
[    5.746718]        [<c02424e4>] ubi_eba_read_leb+0x34/0x424
[    5.752312]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.757562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.762937]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.768437]        [<c016edc0>] ubifs_load_znode+0x88/0x560
[    5.774062]        [<c0155254>] ubifs_lookup_level0+0x190/0x1dc
[    5.780031]        [<c01552e4>] ubifs_tnc_locate+0x44/0x198
[    5.785656]        [<c014c614>] ubifs_iget+0x6c/0x8a4
[    5.790718]        [<c014da64>] ubifs_mount+0xc18/0x171c
[    5.796093]        [<c00b5740>] mount_fs+0x44/0x184
[    5.801000]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.806343]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.811343]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.816250]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.821968]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.827656]        [<c034f398>] kernel_init+0x8/0xe4
[    5.832656]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.837906]
-> #0 (&c->tnc_mutex){+.+...}:
[    5.842250]        [<c004de48>] __lock_acquire+0x14ec/0x1b08
[    5.847968]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.853125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.858812]        [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.864437]        [<c0155a48>] ubifs_tnc_lookup_nm+0x28/0x150
[    5.870312]        [<c016fc18>] ubifs_getxattr+0xc0/0x254
[    5.875750]        [<c018e468>] inode_doinit_with_dentry+0x25c/0x55c
[    5.882125]        [<c018f1a8>] sb_finish_set_opts+0xa4/0x21c
[    5.887906]        [<c019055c>] selinux_set_mnt_opts+0x2ec/0x4b8
[    5.893968]        [<c01907dc>] superblock_doinit+0xb4/0xc0
[    5.899562]        [<c00b51f4>] iterate_supers+0xb4/0xdc
[    5.904906]        [<c01a02e8>] security_load_policy+0x248/0x3c4
[    5.910968]        [<c0194994>] sel_write_load+0x9c/0x6a0
[    5.916406]        [<c00b2148>] vfs_write+0xa0/0x17c
[    5.921406]        [<c00b2450>] sys_write+0x3c/0x70
[    5.926343]        [<c00093a0>] ret_fast_syscall+0x0/0x38
[    5.931781]
[    5.931781] other info that might help us debug this:
[    5.931781]
[    5.939781] Chain exists of:
  &c->tnc_mutex --> &sb->s_type->i_mutex_key#2 --> &isec->lock
[    5.948500]  Possible unsafe locking scenario:
[    5.948500]
[    5.954437]        CPU0                    CPU1
[    5.958968]        ----                    ----
[    5.963500]   lock(&isec->lock);
[    5.966781]                                lock(&sb->s_type->i_mutex_key#2);
[    5.973843]                                lock(&isec->lock);
[    5.979625]   lock(&c->tnc_mutex);
[    5.983062]
[    5.983062]  *** DEADLOCK ***
[    5.983062]
[    5.989000] 4 locks held by systemd/1:
[    5.992781]  #0:  (sel_mutex){+.+.+.}, at: [<c0194918>] sel_write_load+0x20/0x6a0
[    6.000343]  #1:  (&type->s_umount_key#26){.+.+..}, at: [<c00b51d0>] iterate_supers+0x90/0xdc
[    6.008968]  #2:  (&sbsec->lock){+.+.+.}, at: [<c01902d4>] selinux_set_mnt_opts+0x64/0x4b8
[    6.017343]  #3:  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    6.025937]
[    6.025937] stack backtrace:
[    6.030375] [<c000d0f0>] (unwind_backtrace+0x0/0xf0) from [<c0351a2c>] (print_circular_bug+0x25c/0x2a8)
[    6.039843] [<c0351a2c>] (print_circular_bug+0x25c/0x2a8) from [<c004de48>] (__lock_acquire+0x14ec/0x1b08)
[    6.049531] [<c004de48>] (__lock_acquire+0x14ec/0x1b08) from [<c004e8e8>] (lock_acquire+0x64/0x78)
[    6.058531] [<c004e8e8>] (lock_acquire+0x64/0x78) from [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec)
[    6.067531] [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec) from [<c01552d0>] (ubifs_tnc_locate+0x30/0x198)
[    6.076968] [<c01552d0>] (ubifs_tnc_locate+0x30/0x198) from [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150)
[    6.086593] [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150) from [<c016fc18>] (ubifs_getxattr+0xc0/0x254)
[    6.096031] [<c016fc18>] (ubifs_getxattr+0xc0/0x254) from [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c)
[    6.105968] [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c) from [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c)

Quoted 8 lines

[    6.116281] [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c) from [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8)
[    6.126218] [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8) from [<c01907dc>] (superblock_doinit+0xb4/0xc0)
[    6.136000] [<c01907dc>] (superblock_doinit+0xb4/0xc0) from [<c00b51f4>] (iterate_supers+0xb4/0xdc)
[    6.145093] [<c00b51f4>] (iterate_supers+0xb4/0xdc) from [<c01a02e8>] (security_load_policy+0x248/0x3c4)
[    6.154625] [<c01a02e8>] (security_load_policy+0x248/0x3c4) from [<c0194994>] (sel_write_load+0x9c/0x6a0)
[    6.164218] [<c0194994>] (sel_write_load+0x9c/0x6a0) from [<c00b2148>] (vfs_write+0xa0/0x17c)
[    6.172781] [<c00b2148>] (vfs_write+0xa0/0x17c) from [<c00b2450>] (sys_write+0x3c/0x70)
[    6.180843] [<c00b2450>] (sys_write+0x3c/0x70) from [<c00093a0>] (ret_fast_syscall+0x0/0x38)

regards,
Marc

Signature · 4 lines

Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

Artem Bityutskiy

2013-02-13 12:47 UTC #2 lore raw

Re: SELinux + ubifs: possible circular locking dependency

Quoted 8 lines · Marc Kleine-Budde

Hello,
I'm on a arm imx28 v3.8-rc6 (+ a handfull of patches to support the custom board) but no modifications on ubifs, selinux or the vfs layer. And not including the xattr patches by Subodh Nijsure.
When booting with SELinux and lockdep enabled I see this _possible_ circular locking dependency:

I guess one needs to really understand how lockdep works, because it seems there is no direct 'tnc_mutex -> isec->lock', and lockdep somehow deducts this connection inderectly.

However, it seems I see what _may_ be the reason, and here is a patch which I think may fix the issue. Would you please test/review it? It is inlined and also attached.

Quoted 1 line

From a2b29a190227959bdeadf8d412745003c86857ef Mon Sep 17 00:00:00 2001

From: Artem Bityutskiy <[email protected]>
Date: Wed, 13 Feb 2013 13:49:14 +0200
Subject: [PATCH] selinux: do not confuse lockdep

Selinux initializes all per-inode 'isec->lock' mutexes in one single place, which makes lockdep believe they all belong to the same class, which will make lockdep treat all 'isec->lock' mutexes equivalent. This leads to a lockdep false-positive reported by Marc Kleine-Budde <[email protected]> (see at the end).

Frankly, I failed to understand the warning and this fix is more of a guess of what would be the root-cause. I would appreciate if someone could explain me what this warning actually tells, because I cannot see any 'c->tnc_mutex -> isec->lock' chain in the code! Where this chain comes from:

"&c->tnc_mutex --> &sb->s_type->i_mutex_key#2 --> &isec->lock"

The lockdep complaint:

Look at the stacktrace #4: here we have 'debugfs_create_dir()'

[    5.390312] ======================================================
[    5.396500] [ INFO: possible circular locking dependency detected ]
[    5.402781] 3.8.0-rc6-00005-g4f7e39d #49 Not tainted
[    5.407750] -------------------------------------------------------
[    5.414031] systemd/1 is trying to acquire lock:
[    5.418656]  (&c->tnc_mutex){+.+...}, at: [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.426343]
[    5.426343] but task is already holding lock:
[    5.432218]  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.440375]
[    5.440375] which lock already depends on the new lock.
[    5.440375]
[    5.448593]
[    5.448593] the existing dependency chain (in reverse order) is:
[    5.456093]
-> #4 (&isec->lock){+.+.+.}:
[    5.460250]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.465437]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.471125]        [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.477437]        [<c0189bd8>] security_d_instantiate+0x1c/0x34
[    5.483500]        [<c017a614>] debugfs_mknod.part.15.constprop.18+0x94/0x128
[    5.490656]        [<c017a858>] __create_file+0x1b0/0x25c
[    5.496093]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.501781]        [<c0491ce8>] pinctrl_init+0x1c/0xd0
[    5.506968]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.512593]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.518562]        [<c034f398>] kernel_init+0x8/0xe4
[    5.523562]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.528812]
-> #3 (&sb->s_type->i_mutex_key#2){+.+.+.}:
[    5.534312]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.539468]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.545187]        [<c017a6f8>] __create_file+0x50/0x25c
[    5.550531]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.556218]        [<c026cfc4>] clk_debug_create_subtree+0x1c/0x108
[    5.562500]        [<c0495bfc>] clk_debug_init+0x68/0xc0
[    5.567875]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.573468]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.579437]        [<c034f398>] kernel_init+0x8/0xe4
[    5.584437]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.589687]
-> #2 (prepare_lock){+.+.+.}:
[    5.593937]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.599125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.604812]        [<c026d400>] clk_prepare+0x18/0x38
[    5.609906]        [<c023a2f8>] __gpmi_enable_clk+0x30/0xb0
[    5.615531]        [<c023a7bc>] gpmi_begin+0x18/0x530
[    5.620625]        [<c0239244>] gpmi_select_chip+0x3c/0x54
[    5.626156]        [<c02341ac>] nand_do_read_ops+0x7c/0x3e4
[    5.631750]        [<c023483c>] nand_read+0x50/0x74
[    5.636656]        [<c02198e4>] part_read+0x5c/0xa4
[    5.641593]        [<c0217404>] mtd_read+0x84/0xb8
[    5.646406]        [<c02450cc>] ubi_io_read+0xa0/0x2c0
[    5.651593]        [<c0242640>] ubi_eba_read_leb+0x190/0x424
[    5.657281]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.662562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.667906]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.673437]        [<c014e780>] ubifs_read_sb_node+0x54/0x78
[    5.679125]        [<c014f444>] ubifs_read_superblock+0xc60/0x163c
[    5.685343]        [<c014d64c>] ubifs_mount+0x800/0x171c
[    5.690687]        [<c00b5740>] mount_fs+0x44/0x184
[    5.695593]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.700968]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.705968]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.710875]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.716562]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.722281]        [<c034f398>] kernel_init+0x8/0xe4
[    5.727281]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.732531]
-> #1 (&le->mutex){++++..}:
[    5.736625]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.741812]        [<c0356468>] down_read+0x40/0x54
[    5.746718]        [<c02424e4>] ubi_eba_read_leb+0x34/0x424
[    5.752312]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.757562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.762937]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.768437]        [<c016edc0>] ubifs_load_znode+0x88/0x560
[    5.774062]        [<c0155254>] ubifs_lookup_level0+0x190/0x1dc
[    5.780031]        [<c01552e4>] ubifs_tnc_locate+0x44/0x198
[    5.785656]        [<c014c614>] ubifs_iget+0x6c/0x8a4
[    5.790718]        [<c014da64>] ubifs_mount+0xc18/0x171c
[    5.796093]        [<c00b5740>] mount_fs+0x44/0x184
[    5.801000]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.806343]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.811343]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.816250]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.821968]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.827656]        [<c034f398>] kernel_init+0x8/0xe4
[    5.832656]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.837906]
-> #0 (&c->tnc_mutex){+.+...}:
[    5.842250]        [<c004de48>] __lock_acquire+0x14ec/0x1b08
[    5.847968]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.853125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.858812]        [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.864437]        [<c0155a48>] ubifs_tnc_lookup_nm+0x28/0x150
[    5.870312]        [<c016fc18>] ubifs_getxattr+0xc0/0x254
[    5.875750]        [<c018e468>] inode_doinit_with_dentry+0x25c/0x55c
[    5.882125]        [<c018f1a8>] sb_finish_set_opts+0xa4/0x21c
[    5.887906]        [<c019055c>] selinux_set_mnt_opts+0x2ec/0x4b8
[    5.893968]        [<c01907dc>] superblock_doinit+0xb4/0xc0
[    5.899562]        [<c00b51f4>] iterate_supers+0xb4/0xdc
[    5.904906]        [<c01a02e8>] security_load_policy+0x248/0x3c4
[    5.910968]        [<c0194994>] sel_write_load+0x9c/0x6a0
[    5.916406]        [<c00b2148>] vfs_write+0xa0/0x17c
[    5.921406]        [<c00b2450>] sys_write+0x3c/0x70
[    5.926343]        [<c00093a0>] ret_fast_syscall+0x0/0x38
[    5.931781]
[    5.931781] other info that might help us debug this:
[    5.931781]
[    5.939781] Chain exists of:
  &c->tnc_mutex --> &sb->s_type->i_mutex_key#2 --> &isec->lock
[    5.948500]  Possible unsafe locking scenario:
[    5.948500]
[    5.954437]        CPU0                    CPU1
[    5.958968]        ----                    ----
[    5.963500]   lock(&isec->lock);
[    5.966781]                                lock(&sb->s_type->i_mutex_key#2);
[    5.973843]                                lock(&isec->lock);
[    5.979625]   lock(&c->tnc_mutex);
[    5.983062]
[    5.983062]  *** DEADLOCK ***
[    5.983062]
[    5.989000] 4 locks held by systemd/1:
[    5.992781]  #0:  (sel_mutex){+.+.+.}, at: [<c0194918>] sel_write_load+0x20/0x6a0
[    6.000343]  #1:  (&type->s_umount_key#26){.+.+..}, at: [<c00b51d0>] iterate_supers+0x90/0xdc
[    6.008968]  #2:  (&sbsec->lock){+.+.+.}, at: [<c01902d4>] selinux_set_mnt_opts+0x64/0x4b8
[    6.017343]  #3:  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    6.025937]
[    6.025937] stack backtrace:
[    6.030375] [<c000d0f0>] (unwind_backtrace+0x0/0xf0) from [<c0351a2c>] (print_circular_bug+0x25c/0x2a8)
[    6.039843] [<c0351a2c>] (print_circular_bug+0x25c/0x2a8) from [<c004de48>] (__lock_acquire+0x14ec/0x1b08)
[    6.049531] [<c004de48>] (__lock_acquire+0x14ec/0x1b08) from [<c004e8e8>] (lock_acquire+0x64/0x78)
[    6.058531] [<c004e8e8>] (lock_acquire+0x64/0x78) from [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec)
[    6.067531] [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec) from [<c01552d0>] (ubifs_tnc_locate+0x30/0x198)
[    6.076968] [<c01552d0>] (ubifs_tnc_locate+0x30/0x198) from [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150)
[    6.086593] [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150) from [<c016fc18>] (ubifs_getxattr+0xc0/0x254)
[    6.096031] [<c016fc18>] (ubifs_getxattr+0xc0/0x254) from [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c)
[    6.105968] [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c) from [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c)
[    6.116281] [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c) from [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8)
[    6.126218] [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8) from [<c01907dc>] (superblock_doinit+0xb4/0xc0)
[    6.136000] [<c01907dc>] (superblock_doinit+0xb4/0xc0) from [<c00b51f4>] (iterate_supers+0xb4/0xdc)
[    6.145093] [<c00b51f4>] (iterate_supers+0xb4/0xdc) from [<c01a02e8>] (security_load_policy+0x248/0x3c4)
[    6.154625] [<c01a02e8>] (security_load_policy+0x248/0x3c4) from [<c0194994>] (sel_write_load+0x9c/0x6a0)
[    6.164218] [<c0194994>] (sel_write_load+0x9c/0x6a0) from [<c00b2148>] (vfs_write+0xa0/0x17c)
[    6.172781] [<c00b2148>] (vfs_write+0xa0/0x17c) from [<c00b2450>] (sys_write+0x3c/0x70)
[    6.180843] [<c00b2450>] (sys_write+0x3c/0x70) from [<c00093a0>] (ret_fast_syscall+0x0/0x38)

Signed-off-by Artem Bityutskiy <[email protected]>

---
 security/selinux/hooks.c |    1 +
 1 file changed, 1 insertion(+)

security/selinux/hooks.c +1 -0

index ef26e96..328180e 100644
@@ -207,6 +207,7 @@ static int inode_alloc_security(struct inode *inode)
 		return -ENOMEM;
 
 	mutex_init(&isec->lock);
+	lockdep_set_class(&isec->lock, inode->i_sb->s_type->i_mutex_key);
 	INIT_LIST_HEAD(&isec->list);
 	isec->inode = inode;
 	isec->sid = SECINITSID_UNLABELED;

Signature · 6 lines

1.7.10.4


-- 
Best Regards,
Artem Bityutskiy

Quoted 1 line

From a2b29a190227959bdeadf8d412745003c86857ef Mon Sep 17 00:00:00 2001

From: Artem Bityutskiy <[email protected]>
Date: Wed, 13 Feb 2013 13:49:14 +0200
Subject: [PATCH] selinux: do not confuse lockdep

"&c->tnc_mutex --> &sb->s_type->i_mutex_key#2 --> &isec->lock"

The lockdep complaint:

Look at the stacktrace #4: here we have 'debugfs_create_dir()'

[    5.390312] ======================================================
[    5.396500] [ INFO: possible circular locking dependency detected ]
[    5.402781] 3.8.0-rc6-00005-g4f7e39d #49 Not tainted
[    5.407750] -------------------------------------------------------
[    5.414031] systemd/1 is trying to acquire lock:
[    5.418656]  (&c->tnc_mutex){+.+...}, at: [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.426343]
[    5.426343] but task is already holding lock:
[    5.432218]  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.440375]
[    5.440375] which lock already depends on the new lock.
[    5.440375]
[    5.448593]
[    5.448593] the existing dependency chain (in reverse order) is:
[    5.456093]
-> #4 (&isec->lock){+.+.+.}:
[    5.460250]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.465437]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.471125]        [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.477437]        [<c0189bd8>] security_d_instantiate+0x1c/0x34
[    5.483500]        [<c017a614>] debugfs_mknod.part.15.constprop.18+0x94/0x128
[    5.490656]        [<c017a858>] __create_file+0x1b0/0x25c
[    5.496093]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.501781]        [<c0491ce8>] pinctrl_init+0x1c/0xd0
[    5.506968]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.512593]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.518562]        [<c034f398>] kernel_init+0x8/0xe4
[    5.523562]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.528812]
-> #3 (&sb->s_type->i_mutex_key#2){+.+.+.}:
[    5.534312]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.539468]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.545187]        [<c017a6f8>] __create_file+0x50/0x25c
[    5.550531]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.556218]        [<c026cfc4>] clk_debug_create_subtree+0x1c/0x108
[    5.562500]        [<c0495bfc>] clk_debug_init+0x68/0xc0
[    5.567875]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.573468]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.579437]        [<c034f398>] kernel_init+0x8/0xe4
[    5.584437]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.589687]
-> #2 (prepare_lock){+.+.+.}:
[    5.593937]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.599125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.604812]        [<c026d400>] clk_prepare+0x18/0x38
[    5.609906]        [<c023a2f8>] __gpmi_enable_clk+0x30/0xb0
[    5.615531]        [<c023a7bc>] gpmi_begin+0x18/0x530
[    5.620625]        [<c0239244>] gpmi_select_chip+0x3c/0x54
[    5.626156]        [<c02341ac>] nand_do_read_ops+0x7c/0x3e4
[    5.631750]        [<c023483c>] nand_read+0x50/0x74
[    5.636656]        [<c02198e4>] part_read+0x5c/0xa4
[    5.641593]        [<c0217404>] mtd_read+0x84/0xb8
[    5.646406]        [<c02450cc>] ubi_io_read+0xa0/0x2c0
[    5.651593]        [<c0242640>] ubi_eba_read_leb+0x190/0x424
[    5.657281]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.662562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.667906]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.673437]        [<c014e780>] ubifs_read_sb_node+0x54/0x78
[    5.679125]        [<c014f444>] ubifs_read_superblock+0xc60/0x163c
[    5.685343]        [<c014d64c>] ubifs_mount+0x800/0x171c
[    5.690687]        [<c00b5740>] mount_fs+0x44/0x184
[    5.695593]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.700968]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.705968]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.710875]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.716562]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.722281]        [<c034f398>] kernel_init+0x8/0xe4
[    5.727281]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.732531]
-> #1 (&le->mutex){++++..}:
[    5.736625]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.741812]        [<c0356468>] down_read+0x40/0x54
[    5.746718]        [<c02424e4>] ubi_eba_read_leb+0x34/0x424
[    5.752312]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.757562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.762937]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.768437]        [<c016edc0>] ubifs_load_znode+0x88/0x560
[    5.774062]        [<c0155254>] ubifs_lookup_level0+0x190/0x1dc
[    5.780031]        [<c01552e4>] ubifs_tnc_locate+0x44/0x198
[    5.785656]        [<c014c614>] ubifs_iget+0x6c/0x8a4
[    5.790718]        [<c014da64>] ubifs_mount+0xc18/0x171c
[    5.796093]        [<c00b5740>] mount_fs+0x44/0x184
[    5.801000]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.806343]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.811343]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.816250]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.821968]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.827656]        [<c034f398>] kernel_init+0x8/0xe4
[    5.832656]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.837906]
-> #0 (&c->tnc_mutex){+.+...}:
[    5.842250]        [<c004de48>] __lock_acquire+0x14ec/0x1b08
[    5.847968]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.853125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.858812]        [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.864437]        [<c0155a48>] ubifs_tnc_lookup_nm+0x28/0x150
[    5.870312]        [<c016fc18>] ubifs_getxattr+0xc0/0x254
[    5.875750]        [<c018e468>] inode_doinit_with_dentry+0x25c/0x55c
[    5.882125]        [<c018f1a8>] sb_finish_set_opts+0xa4/0x21c
[    5.887906]        [<c019055c>] selinux_set_mnt_opts+0x2ec/0x4b8
[    5.893968]        [<c01907dc>] superblock_doinit+0xb4/0xc0
[    5.899562]        [<c00b51f4>] iterate_supers+0xb4/0xdc
[    5.904906]        [<c01a02e8>] security_load_policy+0x248/0x3c4
[    5.910968]        [<c0194994>] sel_write_load+0x9c/0x6a0
[    5.916406]        [<c00b2148>] vfs_write+0xa0/0x17c
[    5.921406]        [<c00b2450>] sys_write+0x3c/0x70
[    5.926343]        [<c00093a0>] ret_fast_syscall+0x0/0x38
[    5.931781]
[    5.931781] other info that might help us debug this:
[    5.931781]
[    5.939781] Chain exists of:
  &c->tnc_mutex --> &sb->s_type->i_mutex_key#2 --> &isec->lock
[    5.948500]  Possible unsafe locking scenario:
[    5.948500]
[    5.954437]        CPU0                    CPU1
[    5.958968]        ----                    ----
[    5.963500]   lock(&isec->lock);
[    5.966781]                                lock(&sb->s_type->i_mutex_key#2);
[    5.973843]                                lock(&isec->lock);
[    5.979625]   lock(&c->tnc_mutex);
[    5.983062]
[    5.983062]  *** DEADLOCK ***
[    5.983062]
[    5.989000] 4 locks held by systemd/1:
[    5.992781]  #0:  (sel_mutex){+.+.+.}, at: [<c0194918>] sel_write_load+0x20/0x6a0
[    6.000343]  #1:  (&type->s_umount_key#26){.+.+..}, at: [<c00b51d0>] iterate_supers+0x90/0xdc
[    6.008968]  #2:  (&sbsec->lock){+.+.+.}, at: [<c01902d4>] selinux_set_mnt_opts+0x64/0x4b8
[    6.017343]  #3:  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    6.025937]
[    6.025937] stack backtrace:
[    6.030375] [<c000d0f0>] (unwind_backtrace+0x0/0xf0) from [<c0351a2c>] (print_circular_bug+0x25c/0x2a8)
[    6.039843] [<c0351a2c>] (print_circular_bug+0x25c/0x2a8) from [<c004de48>] (__lock_acquire+0x14ec/0x1b08)
[    6.049531] [<c004de48>] (__lock_acquire+0x14ec/0x1b08) from [<c004e8e8>] (lock_acquire+0x64/0x78)
[    6.058531] [<c004e8e8>] (lock_acquire+0x64/0x78) from [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec)
[    6.067531] [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec) from [<c01552d0>] (ubifs_tnc_locate+0x30/0x198)
[    6.076968] [<c01552d0>] (ubifs_tnc_locate+0x30/0x198) from [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150)
[    6.086593] [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150) from [<c016fc18>] (ubifs_getxattr+0xc0/0x254)
[    6.096031] [<c016fc18>] (ubifs_getxattr+0xc0/0x254) from [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c)
[    6.105968] [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c) from [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c)
[    6.116281] [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c) from [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8)
[    6.126218] [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8) from [<c01907dc>] (superblock_doinit+0xb4/0xc0)
[    6.136000] [<c01907dc>] (superblock_doinit+0xb4/0xc0) from [<c00b51f4>] (iterate_supers+0xb4/0xdc)
[    6.145093] [<c00b51f4>] (iterate_supers+0xb4/0xdc) from [<c01a02e8>] (security_load_policy+0x248/0x3c4)
[    6.154625] [<c01a02e8>] (security_load_policy+0x248/0x3c4) from [<c0194994>] (sel_write_load+0x9c/0x6a0)
[    6.164218] [<c0194994>] (sel_write_load+0x9c/0x6a0) from [<c00b2148>] (vfs_write+0xa0/0x17c)
[    6.172781] [<c00b2148>] (vfs_write+0xa0/0x17c) from [<c00b2450>] (sys_write+0x3c/0x70)
[    6.180843] [<c00b2450>] (sys_write+0x3c/0x70) from [<c00093a0>] (ret_fast_syscall+0x0/0x38)

Signed-off-by Artem Bityutskiy <[email protected]>

---
 security/selinux/hooks.c |    1 +
 1 file changed, 1 insertion(+)

security/selinux/hooks.c +1 -0

index ef26e96..328180e 100644
@@ -207,6 +207,7 @@ static int inode_alloc_security(struct inode *inode)
 		return -ENOMEM;
 
 	mutex_init(&isec->lock);
+	lockdep_set_class(&isec->lock, inode->i_sb->s_type->i_mutex_key);
 	INIT_LIST_HEAD(&isec->list);
 	isec->inode = inode;
 	isec->sid = SECINITSID_UNLABELED;

Signature · 1 line

1.7.10.4

Marc Kleine-Budde

author

2013-02-13 14:37 UTC #3 lore raw

Re: SELinux + ubifs: possible circular locking dependency

Quoted 7 lines · Artem Bityutskiy

Quoted 6 lines
I'm on a arm imx28 v3.8-rc6 (+ a handfull of patches to support the custom board) but no modifications on ubifs, selinux or the vfs layer. And not including the xattr patches by Subodh Nijsure.
When booting with SELinux and lockdep enabled I see this _possible_ circular locking dependency:

Quoted 7 lines

I guess one needs to really understand how lockdep works, because it seems there is no direct 'tnc_mutex -> isec->lock', and lockdep somehow deducts this connection inderectly.
However, it seems I see what _may_ be the reason, and here is a patch which I think may fix the issue. Would you please test/review it? It is inlined and also attached.

Thanks,

[...]

The compiler complains

security/selinux/hooks.c:210:2: error: incompatible type for argument 3 of 'lockdep_init_map'
In file included from include/linux/spinlock_types.h:18:0,
from include/linux/spinlock.h:81,
from include/linux/seqlock.h:29,
from include/linux/time.h:5,
from include/uapi/linux/timex.h:56,
from include/linux/timex.h:56,
from include/linux/sched.h:17,
from include/linux/tracehook.h:49,
from security/selinux/hooks.c:29:
include/linux/lockdep.h:279:13: note: expected 'struct lock_class_key *' but argument is of type 'struct lock_class_key'

security/selinux/hooks.c static int inode_alloc_security(struct inode *inode) · line 210

Quoted 9 lines

security/selinux/hooks.c +1 -0

index ef26e96..328180e 100644
@@ -207,6 +207,7 @@ static int inode_alloc_security(struct inode *inode)
 		return -ENOMEM;
 
 	mutex_init(&isec->lock);
+	lockdep_set_class(&isec->lock, inode->i_sb->s_type->i_mutex_key);

So I added an "&", so that the line looks like that:

+ lockdep_set_class(&isec->lock, &inode->i_sb->s_type->i_mutex_key);

security/selinux/hooks.c static int inode_alloc_security(struct inode *inode) · line 213

Quoted 4 lines

security/selinux/hooks.c +0 -0

 	INIT_LIST_HEAD(&isec->list);
 	isec->inode = inode;
 	isec->sid = SECINITSID_UNLABELED;

That solves original circular lock warning, but brings these two:

Quoted 8 lines

[    0.213843] ------------[ cut here ]------------
[    0.218687] WARNING: at kernel/lockdep.c:702 __lock_acquire+0x1824/0x1c58()
[    0.225875] Modules linked in:
[    0.229156] [<c000d0f0>] (unwind_backtrace+0x0/0xf0) from [<c001575c>] (warn_slowpath_common+0x4c/0x64)
[    0.238812] [<c001575c>] (warn_slowpath_common+0x4c/0x64) from [<c0015790>] (warn_slowpath_null+0x1c/0x24)
[    0.248750] [<c0015790>] (warn_slowpath_null+0x1c/0x24) from [<c00548f0>] (__lock_acquire+0x1824/0x1c58)
[    0.258500] [<c00548f0>] (__lock_acquire+0x1824/0x1c58) from [<c0055210>] (lock_acquire+0x88/0x9c)
[    0.267750] [<c0055210>] (lock_acquire+0x88/0x9c) from [<c0390aa4>] (mutex_lock_nested+0x5c/0x2ec)

Quoted 8 lines

[    0.276968] [<c0390aa4>] (mutex_lock_nested+0x5c/0x2ec) from [<c00dcf04>] (lock_mount+0x1c/0xbc)
[    0.286031] [<c00dcf04>] (lock_mount+0x1c/0xbc) from [<c00dd310>] (do_add_mount+0x18/0xc8)
[    0.294531] [<c00dd310>] (do_add_mount+0x18/0xc8) from [<c00de17c>] (do_mount+0x1cc/0x8d0)
[    0.303062] [<c00de17c>] (do_mount+0x1cc/0x8d0) from [<c00de904>] (sys_mount+0x84/0xb8)
[    0.311343] [<c00de904>] (sys_mount+0x84/0xb8) from [<c022cf58>] (devtmpfsd+0x4c/0x2b8)
[    0.319593] [<c022cf58>] (devtmpfsd+0x4c/0x2b8) from [<c0034a58>] (kthread+0xa4/0xb0)
[    0.327656] [<c0034a58>] (kthread+0xa4/0xb0) from [<c0009448>] (ret_from_fork+0x14/0x2c)
[    0.336062] ---[ end trace 1b75b31a2719ed1c ]---

The warning comes from:

	list_for_each_entry(class, hash_head, hash_entry) {
		if (class->key == key) {
			/*
			 * Huh! same key, different name? Did someone trample
			 * on some memory? We're most confused.
			 */
			WARN_ON_ONCE(class->name != lock->name);
			return class;
		}
	}

[...]

Quoted 34 lines

[    0.342000] devtmpfs: initialized
[    0.350187] pinctrl core: initialized pinctrl subsystem
[    0.358000]
[    0.359656] =============================================
[    0.365218] [ INFO: possible recursive locking detected ]
[    0.370812] 3.8.0-rc7-00011-g7a589e1-dirty #108 Tainted: G        W
[    0.377562] ---------------------------------------------
[    0.383125] swapper/1 is trying to acquire lock:
[    0.387906]  (&inode->i_sb->s_type->i_mutex_key#7){+.+.+.}, at: [<c01a988c>] inode_doinit_with_dentry+0x8c/0x55c
[    0.398437]
[    0.398437] but task is already holding lock:
[    0.404562]  (&inode->i_sb->s_type->i_mutex_key#7){+.+.+.}, at: [<c0191bd4>] __create_file+0x50/0x25c
[    0.414093]
[    0.414093] other info that might help us debug this:
[    0.420906]  Possible unsafe locking scenario:
[    0.420906]
[    0.427125]        CPU0
[    0.429687]        ----
[    0.432250]   lock(&inode->i_sb->s_type->i_mutex_key#7);
[    0.437781]   lock(&inode->i_sb->s_type->i_mutex_key#7);
[    0.443312]
[    0.443312]  *** DEADLOCK ***
[    0.443312]
[    0.449593]  May be due to missing lock nesting notation
[    0.449593]
[    0.456687] 1 lock held by swapper/1:
[    0.460500]  #0:  (&inode->i_sb->s_type->i_mutex_key#7){+.+.+.}, at: [<c0191bd4>] __create_file+0x50/0x25c
[    0.470468]
[    0.470468] stack backtrace:
[    0.475125] [<c000d0f0>] (unwind_backtrace+0x0/0xf0) from [<c0054578>] (__lock_acquire+0x14ac/0x1c58)
[    0.484625] [<c0054578>] (__lock_acquire+0x14ac/0x1c58) from [<c0055210>] (lock_acquire+0x88/0x9c)
[    0.493843] [<c0055210>] (lock_acquire+0x88/0x9c) from [<c0390aa4>] (mutex_lock_nested+0x5c/0x2ec)
[    0.503093] [<c0390aa4>] (mutex_lock_nested+0x5c/0x2ec) from [<c01a988c>] (inode_doinit_with_dentry+0x8c/0x55c)
[    0.513468] [<c01a988c>] (inode_doinit_with_dentry+0x8c/0x55c) from [<c01a3f9c>] (security_d_instantiate+0x1c/0x34)

Quoted 8 lines

[    0.524187] [<c01a3f9c>] (security_d_instantiate+0x1c/0x34) from [<c0191af0>] (debugfs_mknod.part.15.constprop.18+0x94/0x128)
[    0.535812] [<c0191af0>] (debugfs_mknod.part.15.constprop.18+0x94/0x128) from [<c0191d34>] (__create_file+0x1b0/0x25c)
[    0.546781] [<c0191d34>] (__create_file+0x1b0/0x25c) from [<c0191e68>] (debugfs_create_dir+0x1c/0x28)
[    0.556312] [<c0191e68>] (debugfs_create_dir+0x1c/0x28) from [<c04d1f58>] (pinctrl_init+0x1c/0xd0)
[    0.565531] [<c04d1f58>] (pinctrl_init+0x1c/0xd0) from [<c0008900>] (do_one_initcall+0x108/0x17c)
[    0.574656] [<c0008900>] (do_one_initcall+0x108/0x17c) from [<c04c3858>] (kernel_init_freeable+0xec/0x1b4)
[    0.584593] [<c04c3858>] (kernel_init_freeable+0xec/0x1b4) from [<c0389af0>] (kernel_init+0x8/0xe4)
[    0.593906] [<c0389af0>] (kernel_init+0x8/0xe4) from [<c0009448>] (ret_from_fork+0x14/0x2c)

Marc

Signature · 4 lines

Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

Artem Bityutskiy

2013-02-14 06:35 UTC #4 lore raw

Re: SELinux + ubifs: possible circular locking dependency

Quoted 3 lines · Marc Kleine-Budde

Review
Quoted 1 line
(quoted diff) +1 -0
+	lockdep_set_class(&isec->lock, inode->i_sb->s_type->i_mutex_key);
So I added an "&", so that the line looks like that:

Yeah, I did not compile it, and for the deadlock of course I have to add own class for isec->lock in the fstype structure. I'll try to come up with another patch. Thanks!

Signature · 2 lines

Best Regards,
Artem Bityutskiy

Artem Bityutskiy

2013-02-14 07:15 UTC #5 lore raw

Re: SELinux + ubifs: possible circular locking dependency

In reply to Marc Kleine-Budde

Mark, how about this one? I compiled it and ran on my fedora 16 with SElinux enabled, no obvious issues.

Quoted 1 line

From a19350097200570571aa522afebb96b34db534f4 Mon Sep 17 00:00:00 2001

From: Artem Bityutskiy <[email protected]>
Date: Thu, 14 Feb 2013 09:07:36 +0200
Subject: [PATCH] selinux: do not confuse lockdep

Selinux has per-inode mutexes called 'isec->lock', and they are initialized in the same place, which makes lockdep treat all of the them as if they were identical. However, locking rules may be a little bit different depending on the file-system, so we should put these locks to separate classes, just like we do for 'i_mutex'. Namely, we should put them to per-FS type classes, which is exactly what this patch does.

The problem this patch intends to fix is a strange lockdep warning, which I, frankly speaking, do not really understand, but I believe the root-cause should be fixed by this patch.

Look at the stacktrace #4: here we have 'debugfs_create_dir()'

[    5.390312] ======================================================
[    5.396500] [ INFO: possible circular locking dependency detected ]
[    5.402781] 3.8.0-rc6-00005-g4f7e39d #49 Not tainted
[    5.407750] -------------------------------------------------------
[    5.414031] systemd/1 is trying to acquire lock:
[    5.418656]  (&c->tnc_mutex){+.+...}, at: [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.426343]
[    5.426343] but task is already holding lock:
[    5.432218]  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.440375]
[    5.440375] which lock already depends on the new lock.
[    5.440375]
[    5.448593]
[    5.448593] the existing dependency chain (in reverse order) is:
[    5.456093]
-> #4 (&isec->lock){+.+.+.}:
[    5.460250]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.465437]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.471125]        [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.477437]        [<c0189bd8>] security_d_instantiate+0x1c/0x34
[    5.483500]        [<c017a614>] debugfs_mknod.part.15.constprop.18+0x94/0x128
[    5.490656]        [<c017a858>] __create_file+0x1b0/0x25c
[    5.496093]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.501781]        [<c0491ce8>] pinctrl_init+0x1c/0xd0
[    5.506968]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.512593]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.518562]        [<c034f398>] kernel_init+0x8/0xe4
[    5.523562]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.528812]
-> #3 (&sb->s_type->i_mutex_key#2){+.+.+.}:
[    5.534312]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.539468]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.545187]        [<c017a6f8>] __create_file+0x50/0x25c
[    5.550531]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.556218]        [<c026cfc4>] clk_debug_create_subtree+0x1c/0x108
[    5.562500]        [<c0495bfc>] clk_debug_init+0x68/0xc0
[    5.567875]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.573468]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.579437]        [<c034f398>] kernel_init+0x8/0xe4
[    5.584437]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.589687]
-> #2 (prepare_lock){+.+.+.}:
[    5.593937]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.599125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.604812]        [<c026d400>] clk_prepare+0x18/0x38
[    5.609906]        [<c023a2f8>] __gpmi_enable_clk+0x30/0xb0
[    5.615531]        [<c023a7bc>] gpmi_begin+0x18/0x530
[    5.620625]        [<c0239244>] gpmi_select_chip+0x3c/0x54
[    5.626156]        [<c02341ac>] nand_do_read_ops+0x7c/0x3e4
[    5.631750]        [<c023483c>] nand_read+0x50/0x74
[    5.636656]        [<c02198e4>] part_read+0x5c/0xa4
[    5.641593]        [<c0217404>] mtd_read+0x84/0xb8
[    5.646406]        [<c02450cc>] ubi_io_read+0xa0/0x2c0
[    5.651593]        [<c0242640>] ubi_eba_read_leb+0x190/0x424
[    5.657281]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.662562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.667906]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.673437]        [<c014e780>] ubifs_read_sb_node+0x54/0x78
[    5.679125]        [<c014f444>] ubifs_read_superblock+0xc60/0x163c
[    5.685343]        [<c014d64c>] ubifs_mount+0x800/0x171c
[    5.690687]        [<c00b5740>] mount_fs+0x44/0x184
[    5.695593]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.700968]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.705968]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.710875]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.716562]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.722281]        [<c034f398>] kernel_init+0x8/0xe4
[    5.727281]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.732531]
-> #1 (&le->mutex){++++..}:
[    5.736625]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.741812]        [<c0356468>] down_read+0x40/0x54
[    5.746718]        [<c02424e4>] ubi_eba_read_leb+0x34/0x424
[    5.752312]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.757562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.762937]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.768437]        [<c016edc0>] ubifs_load_znode+0x88/0x560
[    5.774062]        [<c0155254>] ubifs_lookup_level0+0x190/0x1dc
[    5.780031]        [<c01552e4>] ubifs_tnc_locate+0x44/0x198
[    5.785656]        [<c014c614>] ubifs_iget+0x6c/0x8a4
[    5.790718]        [<c014da64>] ubifs_mount+0xc18/0x171c
[    5.796093]        [<c00b5740>] mount_fs+0x44/0x184
[    5.801000]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.806343]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.811343]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.816250]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.821968]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.827656]        [<c034f398>] kernel_init+0x8/0xe4
[    5.832656]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.837906]
-> #0 (&c->tnc_mutex){+.+...}:
[    5.842250]        [<c004de48>] __lock_acquire+0x14ec/0x1b08
[    5.847968]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.853125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.858812]        [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.864437]        [<c0155a48>] ubifs_tnc_lookup_nm+0x28/0x150
[    5.870312]        [<c016fc18>] ubifs_getxattr+0xc0/0x254
[    5.875750]        [<c018e468>] inode_doinit_with_dentry+0x25c/0x55c
[    5.882125]        [<c018f1a8>] sb_finish_set_opts+0xa4/0x21c
[    5.887906]        [<c019055c>] selinux_set_mnt_opts+0x2ec/0x4b8
[    5.893968]        [<c01907dc>] superblock_doinit+0xb4/0xc0
[    5.899562]        [<c00b51f4>] iterate_supers+0xb4/0xdc
[    5.904906]        [<c01a02e8>] security_load_policy+0x248/0x3c4
[    5.910968]        [<c0194994>] sel_write_load+0x9c/0x6a0
[    5.916406]        [<c00b2148>] vfs_write+0xa0/0x17c
[    5.921406]        [<c00b2450>] sys_write+0x3c/0x70
[    5.926343]        [<c00093a0>] ret_fast_syscall+0x0/0x38
[    5.931781]
[    5.931781] other info that might help us debug this:
[    5.931781]
[    5.939781] Chain exists of:
  &c->tnc_mutex --> &sb->s_type->i_mutex_key#2 --> &isec->lock
[    5.948500]  Possible unsafe locking scenario:
[    5.948500]
[    5.954437]        CPU0                    CPU1
[    5.958968]        ----                    ----
[    5.963500]   lock(&isec->lock);
[    5.966781]                                lock(&sb->s_type->i_mutex_key#2);
[    5.973843]                                lock(&isec->lock);
[    5.979625]   lock(&c->tnc_mutex);
[    5.983062]
[    5.983062]  *** DEADLOCK ***
[    5.983062]
[    5.989000] 4 locks held by systemd/1:
[    5.992781]  #0:  (sel_mutex){+.+.+.}, at: [<c0194918>] sel_write_load+0x20/0x6a0
[    6.000343]  #1:  (&type->s_umount_key#26){.+.+..}, at: [<c00b51d0>] iterate_supers+0x90/0xdc
[    6.008968]  #2:  (&sbsec->lock){+.+.+.}, at: [<c01902d4>] selinux_set_mnt_opts+0x64/0x4b8
[    6.017343]  #3:  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    6.025937]
[    6.025937] stack backtrace:
[    6.030375] [<c000d0f0>] (unwind_backtrace+0x0/0xf0) from [<c0351a2c>] (print_circular_bug+0x25c/0x2a8)
[    6.039843] [<c0351a2c>] (print_circular_bug+0x25c/0x2a8) from [<c004de48>] (__lock_acquire+0x14ec/0x1b08)
[    6.049531] [<c004de48>] (__lock_acquire+0x14ec/0x1b08) from [<c004e8e8>] (lock_acquire+0x64/0x78)
[    6.058531] [<c004e8e8>] (lock_acquire+0x64/0x78) from [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec)
[    6.067531] [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec) from [<c01552d0>] (ubifs_tnc_locate+0x30/0x198)
[    6.076968] [<c01552d0>] (ubifs_tnc_locate+0x30/0x198) from [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150)
[    6.086593] [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150) from [<c016fc18>] (ubifs_getxattr+0xc0/0x254)
[    6.096031] [<c016fc18>] (ubifs_getxattr+0xc0/0x254) from [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c)
[    6.105968] [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c) from [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c)
[    6.116281] [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c) from [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8)
[    6.126218] [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8) from [<c01907dc>] (superblock_doinit+0xb4/0xc0)
[    6.136000] [<c01907dc>] (superblock_doinit+0xb4/0xc0) from [<c00b51f4>] (iterate_supers+0xb4/0xdc)
[    6.145093] [<c00b51f4>] (iterate_supers+0xb4/0xdc) from [<c01a02e8>] (security_load_policy+0x248/0x3c4)
[    6.154625] [<c01a02e8>] (security_load_policy+0x248/0x3c4) from [<c0194994>] (sel_write_load+0x9c/0x6a0)
[    6.164218] [<c0194994>] (sel_write_load+0x9c/0x6a0) from [<c00b2148>] (vfs_write+0xa0/0x17c)
[    6.172781] [<c00b2148>] (vfs_write+0xa0/0x17c) from [<c00b2450>] (sys_write+0x3c/0x70)
[    6.180843] [<c00b2450>] (sys_write+0x3c/0x70) from [<c00093a0>] (ret_fast_syscall+0x0/0x38)

Reported-by Marc Kleine-Budde <[email protected]>

Signed-off-by Artem Bityutskiy <[email protected]>

---
 include/linux/fs.h       |    1 +
 security/selinux/hooks.c |    2 ++
 2 files changed, 3 insertions(+), 0 deletions(-)

include/linux/fs.h +1 -0

index 7617ee0..ccd49e1 100644
@@ -1824,6 +1824,7 @@ struct file_system_type {
 	struct lock_class_key i_lock_key;
 	struct lock_class_key i_mutex_key;
 	struct lock_class_key i_mutex_dir_key;
+	struct lock_class_key i_security_lock_key;
 };
 
 extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,

security/selinux/hooks.c +2 -0

index ef26e96..13ccbb0 100644
@@ -207,6 +207,8 @@ static int inode_alloc_security(struct inode *inode)
 		return -ENOMEM;
 
 	mutex_init(&isec->lock);
+	lockdep_set_class(&isec->lock,
+			  &inode->i_sb->s_type->i_security_lock_key);
 	INIT_LIST_HEAD(&isec->list);
 	isec->inode = inode;
 	isec->sid = SECINITSID_UNLABELED;

Signature · 5 lines

1.7.7.6

-- 
Best Regards,
Artem Bityutskiy

Quoted 1 line

From a19350097200570571aa522afebb96b34db534f4 Mon Sep 17 00:00:00 2001

From: Artem Bityutskiy <[email protected]>
Date: Thu, 14 Feb 2013 09:07:36 +0200
Subject: [PATCH] selinux: do not confuse lockdep

The problem this patch intends to fix is a strange lockdep warning, which I, frankly speaking, do not really understand, but I believe the root-cause should be fixed by this patch.

Look at the stacktrace #4: here we have 'debugfs_create_dir()'

[    5.390312] ======================================================
[    5.396500] [ INFO: possible circular locking dependency detected ]
[    5.402781] 3.8.0-rc6-00005-g4f7e39d #49 Not tainted
[    5.407750] -------------------------------------------------------
[    5.414031] systemd/1 is trying to acquire lock:
[    5.418656]  (&c->tnc_mutex){+.+...}, at: [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.426343]
[    5.426343] but task is already holding lock:
[    5.432218]  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.440375]
[    5.440375] which lock already depends on the new lock.
[    5.440375]
[    5.448593]
[    5.448593] the existing dependency chain (in reverse order) is:
[    5.456093]
-> #4 (&isec->lock){+.+.+.}:
[    5.460250]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.465437]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.471125]        [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    5.477437]        [<c0189bd8>] security_d_instantiate+0x1c/0x34
[    5.483500]        [<c017a614>] debugfs_mknod.part.15.constprop.18+0x94/0x128
[    5.490656]        [<c017a858>] __create_file+0x1b0/0x25c
[    5.496093]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.501781]        [<c0491ce8>] pinctrl_init+0x1c/0xd0
[    5.506968]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.512593]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.518562]        [<c034f398>] kernel_init+0x8/0xe4
[    5.523562]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.528812]
-> #3 (&sb->s_type->i_mutex_key#2){+.+.+.}:
[    5.534312]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.539468]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.545187]        [<c017a6f8>] __create_file+0x50/0x25c
[    5.550531]        [<c017a98c>] debugfs_create_dir+0x1c/0x28
[    5.556218]        [<c026cfc4>] clk_debug_create_subtree+0x1c/0x108
[    5.562500]        [<c0495bfc>] clk_debug_init+0x68/0xc0
[    5.567875]        [<c0008900>] do_one_initcall+0x108/0x17c
[    5.573468]        [<c0483858>] kernel_init_freeable+0xec/0x1b4
[    5.579437]        [<c034f398>] kernel_init+0x8/0xe4
[    5.584437]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.589687]
-> #2 (prepare_lock){+.+.+.}:
[    5.593937]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.599125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.604812]        [<c026d400>] clk_prepare+0x18/0x38
[    5.609906]        [<c023a2f8>] __gpmi_enable_clk+0x30/0xb0
[    5.615531]        [<c023a7bc>] gpmi_begin+0x18/0x530
[    5.620625]        [<c0239244>] gpmi_select_chip+0x3c/0x54
[    5.626156]        [<c02341ac>] nand_do_read_ops+0x7c/0x3e4
[    5.631750]        [<c023483c>] nand_read+0x50/0x74
[    5.636656]        [<c02198e4>] part_read+0x5c/0xa4
[    5.641593]        [<c0217404>] mtd_read+0x84/0xb8
[    5.646406]        [<c02450cc>] ubi_io_read+0xa0/0x2c0
[    5.651593]        [<c0242640>] ubi_eba_read_leb+0x190/0x424
[    5.657281]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.662562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.667906]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.673437]        [<c014e780>] ubifs_read_sb_node+0x54/0x78
[    5.679125]        [<c014f444>] ubifs_read_superblock+0xc60/0x163c
[    5.685343]        [<c014d64c>] ubifs_mount+0x800/0x171c
[    5.690687]        [<c00b5740>] mount_fs+0x44/0x184
[    5.695593]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.700968]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.705968]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.710875]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.716562]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.722281]        [<c034f398>] kernel_init+0x8/0xe4
[    5.727281]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.732531]
-> #1 (&le->mutex){++++..}:
[    5.736625]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.741812]        [<c0356468>] down_read+0x40/0x54
[    5.746718]        [<c02424e4>] ubi_eba_read_leb+0x34/0x424
[    5.752312]        [<c0241b18>] ubi_leb_read+0xac/0x120
[    5.757562]        [<c01503e4>] ubifs_leb_read+0x28/0x8c
[    5.762937]        [<c0151f74>] ubifs_read_node+0x98/0x2a0
[    5.768437]        [<c016edc0>] ubifs_load_znode+0x88/0x560
[    5.774062]        [<c0155254>] ubifs_lookup_level0+0x190/0x1dc
[    5.780031]        [<c01552e4>] ubifs_tnc_locate+0x44/0x198
[    5.785656]        [<c014c614>] ubifs_iget+0x6c/0x8a4
[    5.790718]        [<c014da64>] ubifs_mount+0xc18/0x171c
[    5.796093]        [<c00b5740>] mount_fs+0x44/0x184
[    5.801000]        [<c00cd7ec>] vfs_kern_mount+0x4c/0xc0
[    5.806343]        [<c00cf394>] do_mount+0x18c/0x8d0
[    5.811343]        [<c00cfb5c>] sys_mount+0x84/0xb8
[    5.816250]        [<c0483bc8>] mount_block_root+0x118/0x258
[    5.821968]        [<c0483eac>] prepare_namespace+0x8c/0x17c
[    5.827656]        [<c034f398>] kernel_init+0x8/0xe4
[    5.832656]        [<c0009448>] ret_from_fork+0x14/0x2c
[    5.837906]
-> #0 (&c->tnc_mutex){+.+...}:
[    5.842250]        [<c004de48>] __lock_acquire+0x14ec/0x1b08
[    5.847968]        [<c004e8e8>] lock_acquire+0x64/0x78
[    5.853125]        [<c0355d5c>] mutex_lock_nested+0x5c/0x2ec
[    5.858812]        [<c01552d0>] ubifs_tnc_locate+0x30/0x198
[    5.864437]        [<c0155a48>] ubifs_tnc_lookup_nm+0x28/0x150
[    5.870312]        [<c016fc18>] ubifs_getxattr+0xc0/0x254
[    5.875750]        [<c018e468>] inode_doinit_with_dentry+0x25c/0x55c
[    5.882125]        [<c018f1a8>] sb_finish_set_opts+0xa4/0x21c
[    5.887906]        [<c019055c>] selinux_set_mnt_opts+0x2ec/0x4b8
[    5.893968]        [<c01907dc>] superblock_doinit+0xb4/0xc0
[    5.899562]        [<c00b51f4>] iterate_supers+0xb4/0xdc
[    5.904906]        [<c01a02e8>] security_load_policy+0x248/0x3c4
[    5.910968]        [<c0194994>] sel_write_load+0x9c/0x6a0
[    5.916406]        [<c00b2148>] vfs_write+0xa0/0x17c
[    5.921406]        [<c00b2450>] sys_write+0x3c/0x70
[    5.926343]        [<c00093a0>] ret_fast_syscall+0x0/0x38
[    5.931781]
[    5.931781] other info that might help us debug this:
[    5.931781]
[    5.939781] Chain exists of:
  &c->tnc_mutex --> &sb->s_type->i_mutex_key#2 --> &isec->lock
[    5.948500]  Possible unsafe locking scenario:
[    5.948500]
[    5.954437]        CPU0                    CPU1
[    5.958968]        ----                    ----
[    5.963500]   lock(&isec->lock);
[    5.966781]                                lock(&sb->s_type->i_mutex_key#2);
[    5.973843]                                lock(&isec->lock);
[    5.979625]   lock(&c->tnc_mutex);
[    5.983062]
[    5.983062]  *** DEADLOCK ***
[    5.983062]
[    5.989000] 4 locks held by systemd/1:
[    5.992781]  #0:  (sel_mutex){+.+.+.}, at: [<c0194918>] sel_write_load+0x20/0x6a0
[    6.000343]  #1:  (&type->s_umount_key#26){.+.+..}, at: [<c00b51d0>] iterate_supers+0x90/0xdc
[    6.008968]  #2:  (&sbsec->lock){+.+.+.}, at: [<c01902d4>] selinux_set_mnt_opts+0x64/0x4b8
[    6.017343]  #3:  (&isec->lock){+.+.+.}, at: [<c018e298>] inode_doinit_with_dentry+0x8c/0x55c
[    6.025937]
[    6.025937] stack backtrace:
[    6.030375] [<c000d0f0>] (unwind_backtrace+0x0/0xf0) from [<c0351a2c>] (print_circular_bug+0x25c/0x2a8)
[    6.039843] [<c0351a2c>] (print_circular_bug+0x25c/0x2a8) from [<c004de48>] (__lock_acquire+0x14ec/0x1b08)
[    6.049531] [<c004de48>] (__lock_acquire+0x14ec/0x1b08) from [<c004e8e8>] (lock_acquire+0x64/0x78)
[    6.058531] [<c004e8e8>] (lock_acquire+0x64/0x78) from [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec)
[    6.067531] [<c0355d5c>] (mutex_lock_nested+0x5c/0x2ec) from [<c01552d0>] (ubifs_tnc_locate+0x30/0x198)
[    6.076968] [<c01552d0>] (ubifs_tnc_locate+0x30/0x198) from [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150)
[    6.086593] [<c0155a48>] (ubifs_tnc_lookup_nm+0x28/0x150) from [<c016fc18>] (ubifs_getxattr+0xc0/0x254)
[    6.096031] [<c016fc18>] (ubifs_getxattr+0xc0/0x254) from [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c)
[    6.105968] [<c018e468>] (inode_doinit_with_dentry+0x25c/0x55c) from [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c)
[    6.116281] [<c018f1a8>] (sb_finish_set_opts+0xa4/0x21c) from [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8)
[    6.126218] [<c019055c>] (selinux_set_mnt_opts+0x2ec/0x4b8) from [<c01907dc>] (superblock_doinit+0xb4/0xc0)
[    6.136000] [<c01907dc>] (superblock_doinit+0xb4/0xc0) from [<c00b51f4>] (iterate_supers+0xb4/0xdc)
[    6.145093] [<c00b51f4>] (iterate_supers+0xb4/0xdc) from [<c01a02e8>] (security_load_policy+0x248/0x3c4)
[    6.154625] [<c01a02e8>] (security_load_policy+0x248/0x3c4) from [<c0194994>] (sel_write_load+0x9c/0x6a0)
[    6.164218] [<c0194994>] (sel_write_load+0x9c/0x6a0) from [<c00b2148>] (vfs_write+0xa0/0x17c)
[    6.172781] [<c00b2148>] (vfs_write+0xa0/0x17c) from [<c00b2450>] (sys_write+0x3c/0x70)
[    6.180843] [<c00b2450>] (sys_write+0x3c/0x70) from [<c00093a0>] (ret_fast_syscall+0x0/0x38)

Reported-by Marc Kleine-Budde <[email protected]>

Signed-off-by Artem Bityutskiy <[email protected]>

---
 include/linux/fs.h       |    1 +
 security/selinux/hooks.c |    2 ++
 2 files changed, 3 insertions(+), 0 deletions(-)

include/linux/fs.h +1 -0

index 7617ee0..ccd49e1 100644
@@ -1824,6 +1824,7 @@ struct file_system_type {
 	struct lock_class_key i_lock_key;
 	struct lock_class_key i_mutex_key;
 	struct lock_class_key i_mutex_dir_key;
+	struct lock_class_key i_security_lock_key;
 };
 
 extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,

security/selinux/hooks.c +2 -0

index ef26e96..13ccbb0 100644
@@ -207,6 +207,8 @@ static int inode_alloc_security(struct inode *inode)
 		return -ENOMEM;
 
 	mutex_init(&isec->lock);
+	lockdep_set_class(&isec->lock,
+			  &inode->i_sb->s_type->i_security_lock_key);
 	INIT_LIST_HEAD(&isec->list);
 	isec->inode = inode;
 	isec->sid = SECINITSID_UNLABELED;

Signature · 1 line

1.7.7.6

Marc Kleine-Budde

author

2013-02-14 11:56 UTC #6 lore raw

Re: SELinux + ubifs: possible circular locking dependency

Quoted 15 lines · Artem Bityutskiy

Mark, how about this one? I compiled it and ran on my fedora 16 with SElinux enabled, no obvious issues.
From a19350097200570571aa522afebb96b34db534f4 Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <[email protected]>
Date: Thu, 14 Feb 2013 09:07:36 +0200
Subject: [PATCH] selinux: do not confuse lockdep
Selinux has per-inode mutexes called 'isec->lock', and they are initialized in the same place, which makes lockdep treat all of the them as if they were identical. However, locking rules may be a little bit different depending on the file-system, so we should put these locks to separate classes, just like we do for 'i_mutex'. Namely, we should put them to per-FS type classes, which is exactly what this patch does.

Quoted 3 lines

The problem this patch intends to fix is a strange lockdep warning, which I, frankly speaking, do not really understand, but I believe the root-cause should be fixed by this patch.

Thanks, this works with mainline, but not with my xattr patch series applied.

I get this warnings:

Quoted 64 lines

[   13.659593] ======================================================
[   13.665781] [ INFO: possible circular locking dependency detected ]
[   13.672062] 3.8.0-rc7-00011-gd50987e #113 Not tainted
[   13.677125] -------------------------------------------------------
[   13.683406] touch/81 is trying to acquire lock:
[   13.687968]  (&sb->s_type->i_mutex_key#10){+.+...}, at: [<c0178330>] ubifs_init_security+0x24/0x5c
[   13.697031]
[   13.697031] but task is already holding lock:
[   13.702906]  (&ui->ui_mutex){+.+...}, at: [<c0152a98>] ubifs_create+0xb4/0x1ec
[   13.710218]
[   13.710218] which lock already depends on the new lock.
[   13.710218]
[   13.718406]
[   13.718406] the existing dependency chain (in reverse order) is:
[   13.725906]
-> #1 (&ui->ui_mutex){+.+...}:
[   13.730250]        [<c00548f0>] lock_acquire+0x64/0x78
[   13.735437]        [<c035ea74>] mutex_lock_nested+0x5c/0x2ec
[   13.741156]        [<c014f510>] ubifs_write_begin+0x314/0x500
[   13.746937]        [<c0084998>] generic_file_buffered_write+0x1b4/0x288
[   13.753625]        [<c0086704>] __generic_file_aio_write+0x1bc/0x434
[   13.760000]        [<c00869e4>] generic_file_aio_write+0x68/0xd8
[   13.766031]        [<c014eaec>] ubifs_aio_write+0xf8/0x194
[   13.771562]        [<c00b8994>] do_sync_write+0x94/0xc8
[   13.776843]        [<c00b9148>] vfs_write+0xa0/0x17c
[   13.781843]        [<c00b9450>] sys_write+0x3c/0x70
[   13.786750]        [<c000e400>] ret_fast_syscall+0x0/0x38
[   13.792187]
-> #0 (&sb->s_type->i_mutex_key#10){+.+...}:
[   13.797781]        [<c0053e50>] __lock_acquire+0x14ec/0x1b08
[   13.803468]        [<c00548f0>] lock_acquire+0x64/0x78
[   13.808625]        [<c035ea74>] mutex_lock_nested+0x5c/0x2ec
[   13.814343]        [<c0178330>] ubifs_init_security+0x24/0x5c
[   13.820125]        [<c0152b10>] ubifs_create+0x12c/0x1ec
[   13.825468]        [<c00c40a0>] vfs_create+0xa8/0x118
[   13.830562]        [<c00c6594>] do_last+0x930/0xd4c
[   13.835468]        [<c00c6a58>] path_openat+0xa8/0x4b8
[   13.840625]        [<c00c7168>] do_filp_open+0x2c/0x80
[   13.845812]        [<c00b86e4>] do_sys_open+0xe4/0x170
[   13.850968]        [<c000e400>] ret_fast_syscall+0x0/0x38
[   13.856406]
[   13.856406] other info that might help us debug this:
[   13.856406]
[   13.864437]  Possible unsafe locking scenario:
[   13.864437]
[   13.870375]        CPU0                    CPU1
[   13.874906]        ----                    ----
[   13.879468]   lock(&ui->ui_mutex);
[   13.882906]                                lock(&sb->s_type->i_mutex_key#10);
[   13.890093]                                lock(&ui->ui_mutex);
[   13.896031]   lock(&sb->s_type->i_mutex_key#10);
[   13.900718]
[   13.900718]  *** DEADLOCK ***
[   13.900718]
[   13.906656] 3 locks held by touch/81:
[   13.910312]  #0:  (sb_writers#3){.+.+.+}, at: [<c00d4e68>] mnt_want_write+0x18/0x3c
[   13.918093]  #1:  (&type->i_mutex_dir_key){+.+.+.}, at: [<c00c5fcc>] do_last+0x368/0xd4c
[   13.926281]  #2:  (&ui->ui_mutex){+.+...}, at: [<c0152a98>] ubifs_create+0xb4/0x1ec
[   13.934031]
[   13.934031] stack backtrace:
[   13.938468] [<c00124f0>] (unwind_backtrace+0x0/0xf0) from [<c035a670>] (print_circular_bug+0x25c/0x2a8)
[   13.947906] [<c035a670>] (print_circular_bug+0x25c/0x2a8) from [<c0053e50>] (__lock_acquire+0x14ec/0x1b08)
[   13.957593] [<c0053e50>] (__lock_acquire+0x14ec/0x1b08) from [<c00548f0>] (lock_acquire+0x64/0x78)
[   13.966593] [<c00548f0>] (lock_acquire+0x64/0x78) from [<c035ea74>] (mutex_lock_nested+0x5c/0x2ec)

Quoted 8 lines

[   13.975593] [<c035ea74>] (mutex_lock_nested+0x5c/0x2ec) from [<c0178330>] (ubifs_init_security+0x24/0x5c)
[   13.985187] [<c0178330>] (ubifs_init_security+0x24/0x5c) from [<c0152b10>] (ubifs_create+0x12c/0x1ec)
[   13.994437] [<c0152b10>] (ubifs_create+0x12c/0x1ec) from [<c00c40a0>] (vfs_create+0xa8/0x118)
[   14.003000] [<c00c40a0>] (vfs_create+0xa8/0x118) from [<c00c6594>] (do_last+0x930/0xd4c)
[   14.011125] [<c00c6594>] (do_last+0x930/0xd4c) from [<c00c6a58>] (path_openat+0xa8/0x4b8)
[   14.019343] [<c00c6a58>] (path_openat+0xa8/0x4b8) from [<c00c7168>] (do_filp_open+0x2c/0x80)
[   14.027812] [<c00c7168>] (do_filp_open+0x2c/0x80) from [<c00b86e4>] (do_sys_open+0xe4/0x170)
[   14.036281] [<c00b86e4>] (do_sys_open+0xe4/0x170) from [<c000e400>] (ret_fast_syscall+0x0/0x38)

or this:

Quoted 58 lines

[   54.994687]
[   54.996218] ======================================================
[   55.002437] [ INFO: possible circular locking dependency detected ]
[   55.008718] 3.8.0-rc7-00011-gd50987e #113 Not tainted
[   55.013781] -------------------------------------------------------
[   55.020062] semodule/427 is trying to acquire lock:
[   55.024937]  (&sb->s_type->i_mutex_key#12){+.+.+.}, at: [<c0178330>] ubifs_init_security+0x24/0x5c
[   55.034031]
[   55.034031] but task is already holding lock:
[   55.039875]  (&ui->ui_mutex){+.+...}, at: [<c0152614>] ubifs_mkdir+0x98/0x204
[   55.047125]
[   55.047125] which lock already depends on the new lock.
[   55.047125]
[   55.055312]
[   55.055312] the existing dependency chain (in reverse order) is:
[   55.062812]
-> #1 (&ui->ui_mutex){+.+...}:
[   55.067156]        [<c00548f0>] lock_acquire+0x64/0x78
[   55.072343]        [<c035ea74>] mutex_lock_nested+0x5c/0x2ec
[   55.078031]        [<c014ffb8>] ubifs_setattr+0x2c8/0x3f8
[   55.083500]        [<c00d1b14>] notify_change+0x1dc/0x330
[   55.088937]        [<c00b7838>] do_truncate+0x78/0x9c
[   55.094031]        [<c00c6318>] do_last+0x6b4/0xd4c
[   55.098937]        [<c00c6a58>] path_openat+0xa8/0x4b8
[   55.104125]        [<c00c7168>] do_filp_open+0x2c/0x80
[   55.109281]        [<c00b86e4>] do_sys_open+0xe4/0x170
[   55.114468]        [<c000e400>] ret_fast_syscall+0x0/0x38
[   55.119906]
-> #0 (&sb->s_type->i_mutex_key#12){+.+.+.}:
[   55.125468]        [<c0053e50>] __lock_acquire+0x14ec/0x1b08
[   55.131187]        [<c00548f0>] lock_acquire+0x64/0x78
[   55.136343]        [<c035ea74>] mutex_lock_nested+0x5c/0x2ec
[   55.142062]        [<c0178330>] ubifs_init_security+0x24/0x5c
[   55.147843]        [<c01526b4>] ubifs_mkdir+0x138/0x204
[   55.153093]        [<c00c3e50>] vfs_mkdir+0xb8/0x138
[   55.158093]        [<c00c74bc>] sys_mkdirat+0x5c/0xb0
[   55.163187]        [<c000e400>] ret_fast_syscall+0x0/0x38
[   55.168625]
[   55.168625] other info that might help us debug this:
[   55.168625]
[   55.176625]  Possible unsafe locking scenario:
[   55.176625]
[   55.182562]        CPU0                    CPU1
[   55.187125]        ----                    ----
[   55.191656]   lock(&ui->ui_mutex);
[   55.195093]                                lock(&sb->s_type->i_mutex_key#12);
[   55.202281]                                lock(&ui->ui_mutex);
[   55.208218]   lock(&sb->s_type->i_mutex_key#12);
[   55.212906]
[   55.212906]  *** DEADLOCK ***
[   55.212906]
[   55.218843] 3 locks held by semodule/427:
[   55.222875]  #0:  (sb_writers#3){.+.+.+}, at: [<c00d4e68>] mnt_want_write+0x18/0x3c
[   55.230656]  #1:  (&type->i_mutex_dir_key/1){+.+.+.}, at: [<c00c4ed0>] kern_path_create+0x6c/0x11c
[   55.239718]  #2:  (&ui->ui_mutex){+.+...}, at: [<c0152614>] ubifs_mkdir+0x98/0x204
[   55.247375]
[   55.247375] stack backtrace:
[   55.251812] [<c00124f0>] (unwind_backtrace+0x0/0xf0) from [<c035a670>] (print_circular_bug+0x25c/0x2a8)

Quoted 8 lines

[   55.261250] [<c035a670>] (print_circular_bug+0x25c/0x2a8) from [<c0053e50>] (__lock_acquire+0x14ec/0x1b08)
[   55.270937] [<c0053e50>] (__lock_acquire+0x14ec/0x1b08) from [<c00548f0>] (lock_acquire+0x64/0x78)
[   55.279937] [<c00548f0>] (lock_acquire+0x64/0x78) from [<c035ea74>] (mutex_lock_nested+0x5c/0x2ec)
[   55.288937] [<c035ea74>] (mutex_lock_nested+0x5c/0x2ec) from [<c0178330>] (ubifs_init_security+0x24/0x5c)
[   55.298531] [<c0178330>] (ubifs_init_security+0x24/0x5c) from [<c01526b4>] (ubifs_mkdir+0x138/0x204)
[   55.307687] [<c01526b4>] (ubifs_mkdir+0x138/0x204) from [<c00c3e50>] (vfs_mkdir+0xb8/0x138)
[   55.316062] [<c00c3e50>] (vfs_mkdir+0xb8/0x138) from [<c00c74bc>] (sys_mkdirat+0x5c/0xb0)
[   55.324281] [<c00c74bc>] (sys_mkdirat+0x5c/0xb0) from [<c000e400>] (ret_fast_syscall+0x0/0x38)

Marc

Signature · 4 lines

Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

Artem Bityutskiy

2013-02-14 12:08 UTC #7 lore raw

Re: SELinux + ubifs: possible circular locking dependency

Quoted 16 lines · Marc Kleine-Budde

Quoted 15 lines · Artem Bityutskiy
Mark, how about this one? I compiled it and ran on my fedora 16 with SElinux enabled, no obvious issues.
From a19350097200570571aa522afebb96b34db534f4 Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <[email protected]>
Date: Thu, 14 Feb 2013 09:07:36 +0200
Subject: [PATCH] selinux: do not confuse lockdep
Selinux has per-inode mutexes called 'isec->lock', and they are initialized in the same place, which makes lockdep treat all of the them as if they were identical. However, locking rules may be a little bit different depending on the file-system, so we should put these locks to separate classes, just like we do for 'i_mutex'. Namely, we should put them to per-FS type classes, which is exactly what this patch does.

Quoted 6 lines

Quoted 3 lines
The problem this patch intends to fix is a strange lockdep warning, which I, frankly speaking, do not really understand, but I believe the root-cause should be fixed by this patch.
Thanks, this works with mainline, but not with my xattr patch series applied.

Hmm, probably I have to annotate the ui mutex. Let's drop security mailing lists from the loop so far, I'll come up with a patch tomorrow.

Signature · 2 lines

Best Regards,
Artem Bityutskiy

Marc Kleine-Budde

author

2013-02-20 11:20 UTC #8 lore raw

Re: SELinux + ubifs: possible circular locking dependency

Quoted 21 lines · Artem Bityutskiy

Quoted 20 lines · Marc Kleine-Budde
Quoted 18 lines · Artem Bityutskiy
Mark, how about this one? I compiled it and ran on my fedora 16 with SElinux enabled, no obvious issues.
From a19350097200570571aa522afebb96b34db534f4 Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <[email protected]>
Date: Thu, 14 Feb 2013 09:07:36 +0200
Subject: [PATCH] selinux: do not confuse lockdep
Selinux has per-inode mutexes called 'isec->lock', and they are initialized in the same place, which makes lockdep treat all of the them as if they were identical. However, locking rules may be a little bit different depending on the file-system, so we should put these locks to separate classes, just like we do for 'i_mutex'. Namely, we should put them to per-FS type classes, which is exactly what this patch does.
The problem this patch intends to fix is a strange lockdep warning, which I, frankly speaking, do not really understand, but I believe the root-cause should be fixed by this patch.

Quoted 5 lines

Quoted 2 lines
Thanks, this works with mainline, but not with my xattr patch series applied.
Hmm, probably I have to annotate the ui mutex. Let's drop security mailing lists from the loop so far, I'll come up with a patch tomorrow.

Do you have a patch I can test?

Marc

Signature · 4 lines

Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

Artem Bityutskiy

2013-02-20 11:23 UTC #9 lore raw

Re: SELinux + ubifs: possible circular locking dependency

Quoted 4 lines · Marc Kleine-Budde

Quoted 2 lines
Hmm, probably I have to annotate the ui mutex. Let's drop security mailing lists from the loop so far, I'll come up with a patch tomorrow.
Do you have a patch I can test?

Mark, I apologise for not keeping my promise, I got distracted. I will _try_ to look at this again this week. Sorry!

Signature · 2 lines

Best Regards,
Artem Bityutskiy

Marc Kleine-Budde

author

2013-02-20 11:39 UTC #10 lore raw

Re: SELinux + ubifs: possible circular locking dependency

Quoted 8 lines · Artem Bityutskiy

Quoted 4 lines · Marc Kleine-Budde
Quoted 2 lines
Hmm, probably I have to annotate the ui mutex. Let's drop security mailing lists from the loop so far, I'll come up with a patch tomorrow.
Do you have a patch I can test?
Mark, I apologise for not keeping my promise, I got distracted. I will _try_ to look at this again this week. Sorry!

I know what you're talking about ;), no problem.

regards,
Marc

Signature · 4 lines

Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |