jesper.juhl at gmail
Jun 30, 2007, 4:16 PM
Post #1 of 4
(137 views)
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[PATCH][XFS][resend] fix memory leak in xfs_inactive()
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(this is back from May 16 2007, resending since it doesn't look like
the patch ever made it in anywhere)
The Coverity checker found a memory leak in xfs_inactive().
The offending code is this bit :
1671 tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
At conditional (1): "truncate != 0" taking true path
1672 if (truncate) {
1673 /*
1674 * Do the xfs_itruncate_start() call before
1675 * reserving any log space because itruncate_start
1676 * will call into the buffer cache and we can't
1677 * do that within a transaction.
1678 */
1679 xfs_ilock(ip, XFS_IOLOCK_EXCL);
1680
1681 error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE, 0);
At conditional (2): "error != 0" taking true path
1682 if (error) {
1683 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
Event leaked_storage: Returned without freeing storage "tp"
Also see events: [alloc_fn][var_assign]
1684 return VN_INACTIVE_CACHE;
1685 }
So, the code allocates a transaction, but in the case where 'truncate' is !=0 and xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE, 0); happens to return an error, we'll just return from the function without dealing with the memory allocated byxfs_trans_alloc() and assigned to 'tp', thus it'll be orphaned/leaked - not good.
The bug was introduced by this commit:
http://git2.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d3cf209476b72c83907a412b6708c5e498410aa7
The patch below is
From: Dave Chinner <dgc[at]sgi.com>
Signed-off-by: Jesper Juhl <jesper.juhl[at]gmail.com>
---
fs/xfs/xfs_vnodeops.c | 1 +
1 file changed, 1 insertion(+)
Index: 2.6.x-xfs-new/fs/xfs/xfs_vnodeops.c
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/xfs_vnodeops.c 2007-05-11 16:04:03.000000000 +1000
+++ 2.6.x-xfs-new/fs/xfs/xfs_vnodeops.c 2007-05-17 12:37:25.671399078 +1000
@@ -1710,6 +1710,7 @@ xfs_inactive(
error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE, 0);
if (error) {
+ xfs_trans_cancel(tp, 0);
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
return VN_INACTIVE_CACHE;
}
-
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