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]
[<c01f33a4>] ? pcpu_alloc+0x714/0x810
[<c02d2add>] ? ida_get_new_above+0x1ad/0x230
[<c02d2add>] ? ida_get_new_above+0x1ad/0x230
[<c0226636>] mount_fs+0x36/0x180
[<c01f34af>] ? __alloc_percpu+0xf/0x20
[<c023d961>] vfs_kern_mount+0x51/0xa0
[<c023ddae>] do_kern_mount+0x3e/0xe0
[<c023f189>] do_mount+0x169/0x700
[<c01eeb29>] ? strndup_user+0x49/0x70
[<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@xxxxxxxxx>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
Tested-by: Slicky Devil <slicky.dvl@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 2.6.30+
---
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 8a75901..501b7f8 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]) {
--
1.7.7.4
--
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