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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2012-03-16 17:08:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-16 17:14:44 -0700
commitd7178c79d9b7c5518f9943188091a75fc6ce0675 (patch)
tree6389bdb07d2788357dacbb7dde698e318745591e
parent3d777a64066f3b9db8a94834aaed6a9cf09808fd (diff)
nilfs2: fix NULL pointer dereference in nilfs_load_super_block()
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> Cc: <stable@vger.kernel.org> [2.6.30+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/nilfs2/the_nilfs.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 8a759016c2e3..501b7f8b739f 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -521,6 +521,7 @@ 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]) {