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authorLachlan McIlroy <lmcilroy@redhat.com>2009-04-23 22:18:00 -0400
committerFelix Blyakher <felixb@sgi.com>2009-04-29 09:14:10 -0500
commitf25181f598cf4a8ccc40a51d8b74f8b555ecddee (patch)
treec27dcad813a3e5aeb8c96017ff1a81f736dfef08 /fs/xfs
parent8de2bf937a6bea8f0f775fd5399ba20c1a0c3d77 (diff)
xfs_file_last_byte() needs to acquire ilock
We had some systems crash with this stack: [<a00000010000cb20>] ia64_leave_kernel+0x0/0x280 [<a00000021291ca00>] xfs_bmbt_get_startoff+0x0/0x20 [xfs] [<a0000002129080b0>] xfs_bmap_last_offset+0x210/0x280 [xfs] [<a00000021295b010>] xfs_file_last_byte+0x70/0x1a0 [xfs] [<a00000021295b200>] xfs_itruncate_start+0xc0/0x1a0 [xfs] [<a0000002129935f0>] xfs_inactive_free_eofblocks+0x290/0x460 [xfs] [<a000000212998fb0>] xfs_release+0x1b0/0x240 [xfs] [<a0000002129ad930>] xfs_file_release+0x70/0xa0 [xfs] [<a000000100162ea0>] __fput+0x1a0/0x420 [<a000000100163160>] fput+0x40/0x60 The problem here is that xfs_file_last_byte() does not acquire the inode lock and can therefore race with another thread that is modifying the extext list. While xfs_bmap_last_offset() is trying to lookup what was the last extent some extents were merged and the extent list shrunk so the index we lookup is now beyond the end of the extent list and potentially in a freed buffer. Signed-off-by: Lachlan McIlroy <lmcilroy@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Felix Blyakher <felixb@sgi.com> Signed-off-by: Felix Blyakher <felixb@sgi.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_inode.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index e7ae08d1df4..123b20c8cbf 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1258,8 +1258,10 @@ xfs_file_last_byte(
* necessary.
*/
if (ip->i_df.if_flags & XFS_IFEXTENTS) {
+ xfs_ilock(ip, XFS_ILOCK_SHARED);
error = xfs_bmap_last_offset(NULL, ip, &last_block,
XFS_DATA_FORK);
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (error) {
last_block = 0;
}