btrfs triggered lockdep WARN.

Another bug caused by this script. https://github.com/kernelslacker/io-tests/blob/master/setup.sh

Quoting Dave Jones (2013-06-27 10:58:24)

Quoted 1 line

Another bug caused by this script. https://github.com/kernelslacker/io-tests/blob/master/setup.sh

I'm still struggling to reproduce that one here. I've tried every variation I can think of but I'll try again.

I really hope you don't already have CONFIG_DEBUG_PAGE_ALLOC turned on, maybe it will catch this?

Quoted 5 lines

Quoting Dave Jones (2013-06-27 10:58:24)

Quoted 1 line

Another bug caused by this script. https://github.com/kernelslacker/io-tests/blob/master/setup.sh

I'm still struggling to reproduce that one here. I've tried every variation I can think of but I'll try again.

Note that this is a different trace to the other post about that script.

Quoted 3 lines

I really hope you don't already have CONFIG_DEBUG_PAGE_ALLOC turned on, maybe it will catch this?

I do. Though given this is lockdep complaining about what looks like memory corruption, it's probably not related.

Quoted 5 lines

Quoted 2 lines

I really hope you don't already have CONFIG_DEBUG_PAGE_ALLOC turned on, maybe it will catch this?

I do. Though given this is lockdep complaining about what looks like memory corruption, it's probably not related.

Ok, could you please try this with some heavy memory pressure? I'm hoping to trigger a use-after-free that points us in the right direction.

Another bug caused by this script. https://github.com/kernelslacker/io-tests/blob/master/setup.sh

WARNING: at kernel/lockdep.c:708 __lock_acquire+0x183b/0x1b70()
Modules linked in: sctp lec bridge 8021q garp stp mrp fuse dlci tun bnep hidp rfcomm l2tp_ppp l2tp_netlink l2tp_core vmw_vsock_vmci_transport vmw_vmci vsock cmtp kernelcapi nfnetlink ipt_ULOG scsi_transport_iscsi rose phonet rds irda nfc ipx p8023 p8022 netrom af_key can_raw ax25 llc2 af_802154 x25 pppoe caif_socket pppox can_bcm caif ppp_generic slhc crc_ccitt atm appletalk af_rxrpc psnap llc can btrfs kvm_amd kvm snd_hda_codec_realtek snd_hda_intel btusb snd_hda_codec xor bluetooth raid6_pq serio_raw snd_pcm microcode pcspkr libcrc32c zlib_deflate snd_page_alloc snd_timer snd rfkill edac_core soundcore r8169 mii sr_mod cdrom pata_atiixp radeon backlight drm_kms_helper ttm
CPU: 3 PID: 2340684 Comm: rm Not tainted 3.10.0-rc7+ #8 
Hardware name: Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H, BIOS F12a 04/23/2010
 ffffffff819fb83b ffff88010a751aa0 ffffffff816aed7b ffff88010a751ad8
 ffffffff810432b0 0000000000000002 ffffffff8253e3d0 ffff88002e1a9810
 00017ee5aac67d60 0000000000000000 ffff88010a751ae8 ffffffff8104339a
Call Trace:
 [<ffffffff816aed7b>] dump_stack+0x19/0x1b
 [<ffffffff810432b0>] warn_slowpath_common+0x70/0xa0
 [<ffffffff8104339a>] warn_slowpath_null+0x1a/0x20
 [<ffffffff810ba40b>] __lock_acquire+0x183b/0x1b70
 [<ffffffff81333bd0>] ? delay_tsc+0x90/0xe0
 [<ffffffff810baee3>] lock_acquire+0x93/0x1e0
 [<ffffffffa040f937>] ? btrfs_try_tree_write_lock+0x47/0xc0 [btrfs]
 [<ffffffff816b6c11>] _raw_write_lock+0x41/0x80
 [<ffffffffa040f937>] ? btrfs_try_tree_write_lock+0x47/0xc0 [btrfs]
 [<ffffffffa040f937>] btrfs_try_tree_write_lock+0x47/0xc0 [btrfs]
 [<ffffffffa03b4bad>] btrfs_search_slot+0x80d/0x950 [btrfs]
 [<ffffffffa03cd3a6>] btrfs_del_inode_ref+0x76/0x3b0 [btrfs]
 [<ffffffffa03f3469>] ? release_extent_buffer+0xb9/0xe0 [btrfs]
 [<ffffffffa03f9aaf>] ? free_extent_buffer+0x4f/0xa0 [btrfs]
 [<ffffffffa03e0091>] __btrfs_unlink_inode+0x181/0x390 [btrfs]
 [<ffffffffa03e2e17>] btrfs_unlink_inode+0x27/0x50 [btrfs]
 [<ffffffffa03e2ead>] btrfs_unlink+0x6d/0xc0 [btrfs]
 [<ffffffff811bfb60>] vfs_unlink+0xa0/0x110
 [<ffffffff811bfd47>] do_unlinkat+0x177/0x230
 [<ffffffff810b8815>] ? trace_hardirqs_on_caller+0x115/0x1e0
 [<ffffffff810b88ed>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff8100f525>] ? syscall_trace_enter+0x25/0x290
 [<ffffffff811c274b>] SyS_unlinkat+0x1b/0x40
 [<ffffffff816bf394>] tracesys+0xdd/0xe2
---[ end trace 9d90045eda25c268 ]---

That WARN is..

704 /*

 705                          * Huh! same key, different name? Did someone trample
 706                          * on some memory? We're most confused.
 707                          */

708 WARN_ON_ONCE(class->name != lock->name);

Most confusing indeed.