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btrfs crash - Null dereference - 3.7.0-rc5-00068-gc5e35d6

DISCUSSION Gustavo Padovan 2 participants 5 messages Nov 19, 2012 Btrfs file system

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#1 lore raw
Quoted 9 lines · Gustavo Padovan

Hi,

my system suddenly crashed and gave me this dump:

http://imgur.com/oO6S0

I checked and there is not btrfs commit in linus' tree since I compiled this kernel.

Hi Gustavo,

It's weird that NULL pointer oops happens here.

Since you own the kernel, you may also have debuginfo left,

can you please run
'gdb fs/btrfs/btrfs.ko' and 'list *block_rsv_release_bytes+0x21' to check which one is NULL pointer?

thanks,
liubo

Quoted 5 lines

Gustavo
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author
#2 lore raw

Hi Liu,

Quoted 13 lines · Liu Bo
Quoted 9 lines · Gustavo Padovan

Hi,

my system suddenly crashed and gave me this dump:

http://imgur.com/oO6S0

I checked and there is not btrfs commit in linus' tree since I compiled this kernel.

Hi Gustavo,

Quoted 7 lines

It's weird that NULL pointer oops happens here.

Since you own the kernel, you may also have debuginfo left,

can you please run
'gdb fs/btrfs/btrfs.ko' and 'list *block_rsv_release_bytes+0x21' to check which one is NULL pointer?

(gdb) list *block_rsv_release_bytes+0x21
0xffffffff811a83c1 is in block_rsv_release_bytes
(fs/btrfs/extent-tree.c:4065).
4060
4061 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4062 struct btrfs_block_rsv *block_rsv,
4063 struct btrfs_block_rsv *dest, u64
num_bytes)
4064 {
4065 struct btrfs_space_info *space_info = block_rsv->space_info;
4066
4067 spin_lock(&block_rsv->lock);
4068 if (num_bytes == (u64)-1)
4069 num_bytes = block_rsv->size;
(gdb)

Seems block_rsv is NULL here and looking to btrfs_block_rsv_release() it can only be NULL at this point if global_rsv->full is true otherwise the crash would happen there. I didn't go any further than this.

Gustavo

#3 lore raw
Quoted 21 lines · Gustavo Padovan
Quoted 3 lines

can you please run
'gdb fs/btrfs/btrfs.ko' and 'list *block_rsv_release_bytes+0x21' to check which one is NULL pointer?

(gdb) list *block_rsv_release_bytes+0x21
0xffffffff811a83c1 is in block_rsv_release_bytes
(fs/btrfs/extent-tree.c:4065).
4060
4061 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4062 struct btrfs_block_rsv *block_rsv,
4063 struct btrfs_block_rsv *dest, u64
num_bytes)
4064 {
4065 struct btrfs_space_info *space_info = block_rsv->space_info;
4066
4067 spin_lock(&block_rsv->lock);
4068 if (num_bytes == (u64)-1)
4069 num_bytes = block_rsv->size;
(gdb)

Quoted 5 lines

Seems block_rsv is NULL here and looking to btrfs_block_rsv_release() it can only be NULL at this point if global_rsv->full is true otherwise the crash would happen there. I didn't go any further than this.

Gustavo

Can you check if the following commit is in your tree?

commit 321f0e70225abc792d74902a2bc4a60164265fd4
Author: Miao Xie <[email protected]>

Btrfs: fix wrong orphan count of the fs/file tree

fs/btrfs/inode.c +1 -1
index 878116d..a6824bd 100644
@@ -2228,7 +2228,7 @@ int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
                        insert = 1;
 #endif
                insert = 1;
-               atomic_dec(&root->orphan_inodes);
+               atomic_inc(&root->orphan_inodes);
        }
 
        if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,

thanks,
liubo

author
#4 lore raw
Quoted 40 lines · Liu Bo
Quoted 21 lines · Gustavo Padovan
Quoted 3 lines

can you please run
'gdb fs/btrfs/btrfs.ko' and 'list *block_rsv_release_bytes+0x21' to check which one is NULL pointer?

(gdb) list *block_rsv_release_bytes+0x21
0xffffffff811a83c1 is in block_rsv_release_bytes
(fs/btrfs/extent-tree.c:4065).
4060
4061 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4062 struct btrfs_block_rsv *block_rsv,
4063 struct btrfs_block_rsv *dest, u64
num_bytes)
4064 {
4065 struct btrfs_space_info *space_info = block_rsv->space_info;
4066
4067 spin_lock(&block_rsv->lock);
4068 if (num_bytes == (u64)-1)
4069 num_bytes = block_rsv->size;
(gdb)

Quoted 5 lines

Seems block_rsv is NULL here and looking to btrfs_block_rsv_release() it can only be NULL at this point if global_rsv->full is true otherwise the crash would happen there. I didn't go any further than this.

Gustavo

Can you check if the following commit is in your tree?

commit 321f0e70225abc792d74902a2bc4a60164265fd4
Author: Miao Xie <[email protected]>

Btrfs: fix wrong orphan count of the fs/file tree

fs/btrfs/inode.c +0 -0
index 878116d..a6824bd 100644

fs/btrfs/inode.c int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode) · line 2234

Quoted 8 lines
fs/btrfs/inode.c +1 -1
@@ -2228,7 +2228,7 @@ int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
                        insert = 1;
 #endif
                insert = 1;
-               atomic_dec(&root->orphan_inodes);
+               atomic_inc(&root->orphan_inodes);
        }
 
        if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,

Yes, it is. I'm using linus tree from last week, head at c5e35d6.

Gustavo