2014-10-15 21:23:16

by Alexey Khoroshilov

Subject: [PATCH] xfs: fix deadlock on failure path in xfs_setattr_nonsize()

If xfs_trans_reserve() fails, xfs_setattr_nonsize() does not deallocate
the transaction and does not release "freeze" lock. That leads to the
following warning from lockdep:
[ BUG: lock held when returning to user space! ]
------------------------------------------------
fs-driver-tests/7127 is leaving the kernel with locks still held!
1 lock held by fs-driver-tests/7127:
#0: (sb_internal){.+.+.+}, at: [<ffffffffa0389a44>] xfs_trans_alloc+0x24/0x40 [xfs]

The patch adds xfs_trans_cancel() on the failure path.

Found by Linux File System Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <[email protected]>
---
fs/xfs/xfs_iops.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 72129493e9d3..e2e785eec831 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -599,8 +599,10 @@ xfs_setattr_nonsize(

tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_ichange, 0, 0);
- if (error)
+ if (error) {
+ xfs_trans_cancel(tp, 0);
goto out_dqrele;
+ }

xfs_ilock(ip, XFS_ILOCK_EXCL);

--
1.9.1

2014-10-16 12:41:00

by Brian Foster

Subject: Re: [PATCH] xfs: fix deadlock on failure path in xfs_setattr_nonsize()

On Wed, Oct 15, 2014 at 11:22:48PM +0200, Alexey Khoroshilov wrote:
> If xfs_trans_reserve() fails, xfs_setattr_nonsize() does not deallocate
> the transaction and does not release "freeze" lock. That leads to the
> following warning from lockdep:
> [ BUG: lock held when returning to user space! ]
> ------------------------------------------------
> fs-driver-tests/7127 is leaving the kernel with locks still held!
> 1 lock held by fs-driver-tests/7127:
> #0: (sb_internal){.+.+.+}, at: [<ffffffffa0389a44>] xfs_trans_alloc+0x24/0x40 [xfs]
>
> The patch adds xfs_trans_cancel() on the failure path.
>
> Found by Linux File System Verification project (linuxtesting.org).
>
> Signed-off-by: Alexey Khoroshilov <[email protected]>
> ---

Looks good, thanks for the patch.

Reviewed-by: Brian Foster <[email protected]>

> fs/xfs/xfs_iops.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 72129493e9d3..e2e785eec831 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -599,8 +599,10 @@ xfs_setattr_nonsize(
>
> tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
> error = xfs_trans_reserve(tp, &M_RES(mp)->tr_ichange, 0, 0);
> - if (error)
> + if (error) {
> + xfs_trans_cancel(tp, 0);
> goto out_dqrele;
> + }
>
> xfs_ilock(ip, XFS_ILOCK_EXCL);
>
> --
> 1.9.1
>