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| author | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2012-03-16 17:08:39 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-03-23 11:20:50 -0700 |
| commit | f4565db7fa0694572ac50b8615c7ac3dc936e012 (patch) | |
| tree | a26e5bd1b8d4510f878a6eda8a999cf4511b98c2 /fs/nilfs2 | |
| parent | 9bf176a3e029ae7f2dc6feae185091525a988be2 (diff) | |
| download | lwn-f4565db7fa0694572ac50b8615c7ac3dc936e012.tar.gz lwn-f4565db7fa0694572ac50b8615c7ac3dc936e012.zip | |
nilfs2: fix NULL pointer dereference in nilfs_load_super_block()
commit d7178c79d9b7c5518f9943188091a75fc6ce0675 upstream.
According to the report from Slicky Devil, nilfs caused kernel oops at
nilfs_load_super_block function during mount after he shrank the
partition without resizing the filesystem:
BUG: unable to handle kernel NULL pointer dereference at 00000048
IP: [<d0d7a08e>] nilfs_load_super_block+0x17e/0x280 [nilfs2]
*pde = 00000000
Oops: 0000 [#1] PREEMPT SMP
...
Call Trace:
[<d0d7a87b>] init_nilfs+0x4b/0x2e0 [nilfs2]
[<d0d6f707>] nilfs_mount+0x447/0x5b0 [nilfs2]
[<c0226636>] mount_fs+0x36/0x180
[<c023d961>] vfs_kern_mount+0x51/0xa0
[<c023ddae>] do_kern_mount+0x3e/0xe0
[<c023f189>] do_mount+0x169/0x700
[<c023fa9b>] sys_mount+0x6b/0xa0
[<c04abd1f>] sysenter_do_call+0x12/0x28
Code: 53 18 8b 43 20 89 4b 18 8b 4b 24 89 53 1c 89 43 24 89 4b 20 8b 43
20 c7 43 2c 00 00 00 00 23 75 e8 8b 50 68 89 53 28 8b 54 b3 20 <8b> 72
48 8b 7a 4c 8b 55 08 89 b3 84 00 00 00 89 bb 88 00 00 00
EIP: [<d0d7a08e>] nilfs_load_super_block+0x17e/0x280 [nilfs2] SS:ESP 0068:ca9bbdcc
CR2: 0000000000000048
This turned out due to a defect in an error path which runs if the
calculated location of the secondary super block was invalid.
This patch fixes it and eliminates the reported oops.
Reported-by: Slicky Devil <slicky.dvl@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Slicky Devil <slicky.dvl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/nilfs2')
| -rw-r--r-- | fs/nilfs2/the_nilfs.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index d32714094375..35a89708b635 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -515,6 +515,7 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs, brelse(sbh[1]); sbh[1] = NULL; sbp[1] = NULL; + valid[1] = 0; swp = 0; } if (!valid[swp]) { |