* [PATCH] xfs: fix unreachable BIGTIME check in dquot flush validation
@ 2026-06-03 20:41 Alexey Nepomnyashih
2026-06-03 21:08 ` Darrick J. Wong
2026-06-09 7:26 ` Carlos Maiolino
0 siblings, 2 replies; 4+ messages in thread
From: Alexey Nepomnyashih @ 2026-06-03 20:41 UTC (permalink / raw)
To: Carlos Maiolino
Cc: Alexey Nepomnyashih, Darrick J. Wong, Allison Collins,
Dave Chinner, linux-xfs, linux-kernel, lvc-project, stable
The dqp->q_id == 0 check inside the XFS_DQTYPE_BIGTIME block is
unreachable because root dquots return successfully earlier. Reject root
dquots with XFS_DQTYPE_BIGTIME before that early return, preserving the
intended validation and removing the unreachable condition.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 4ea1ff3b4968 ("xfs: widen ondisk quota expiration timestamps to handle y2038+")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Alexey Nepomnyashih <sdl@nppct.ru>
---
fs/xfs/xfs_dquot.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index 69e9bc588c8b..c311f61d9554 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -1216,6 +1216,14 @@ xfs_qm_dqflush_check(
type != XFS_DQTYPE_PROJ)
return __this_address;
+ /* bigtime flag should never be set on root dquots */
+ if (dqp->q_type & XFS_DQTYPE_BIGTIME) {
+ if (!xfs_has_bigtime(dqp->q_mount))
+ return __this_address;
+ if (dqp->q_id == 0)
+ return __this_address;
+ }
+
if (dqp->q_id == 0)
return NULL;
@@ -1231,14 +1239,6 @@ xfs_qm_dqflush_check(
!dqp->q_rtb.timer)
return __this_address;
- /* bigtime flag should never be set on root dquots */
- if (dqp->q_type & XFS_DQTYPE_BIGTIME) {
- if (!xfs_has_bigtime(dqp->q_mount))
- return __this_address;
- if (dqp->q_id == 0)
- return __this_address;
- }
-
return NULL;
}
--
2.43.0
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] xfs: fix unreachable BIGTIME check in dquot flush validation
2026-06-03 20:41 [PATCH] xfs: fix unreachable BIGTIME check in dquot flush validation Alexey Nepomnyashih
@ 2026-06-03 21:08 ` Darrick J. Wong
2026-06-05 4:18 ` Allison Henderson
2026-06-09 7:26 ` Carlos Maiolino
1 sibling, 1 reply; 4+ messages in thread
From: Darrick J. Wong @ 2026-06-03 21:08 UTC (permalink / raw)
To: Alexey Nepomnyashih
Cc: Carlos Maiolino, Darrick J. Wong, Allison, Dave Chinner,
linux-xfs, linux-kernel, lvc-project, stable
[fix some addresses]
On Wed, Jun 03, 2026 at 08:41:47PM +0000, Alexey Nepomnyashih wrote:
> The dqp->q_id == 0 check inside the XFS_DQTYPE_BIGTIME block is
> unreachable because root dquots return successfully earlier. Reject root
> dquots with XFS_DQTYPE_BIGTIME before that early return, preserving the
> intended validation and removing the unreachable condition.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 4ea1ff3b4968 ("xfs: widen ondisk quota expiration timestamps to handle y2038+")
> Cc: stable@vger.kernel.org # v5.10+
> Signed-off-by: Alexey Nepomnyashih <sdl@nppct.ru>
Yeah, that looks like a screwup...
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
--D
> ---
> fs/xfs/xfs_dquot.c | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
> index 69e9bc588c8b..c311f61d9554 100644
> --- a/fs/xfs/xfs_dquot.c
> +++ b/fs/xfs/xfs_dquot.c
> @@ -1216,6 +1216,14 @@ xfs_qm_dqflush_check(
> type != XFS_DQTYPE_PROJ)
> return __this_address;
>
> + /* bigtime flag should never be set on root dquots */
> + if (dqp->q_type & XFS_DQTYPE_BIGTIME) {
> + if (!xfs_has_bigtime(dqp->q_mount))
> + return __this_address;
> + if (dqp->q_id == 0)
> + return __this_address;
> + }
> +
> if (dqp->q_id == 0)
> return NULL;
>
> @@ -1231,14 +1239,6 @@ xfs_qm_dqflush_check(
> !dqp->q_rtb.timer)
> return __this_address;
>
> - /* bigtime flag should never be set on root dquots */
> - if (dqp->q_type & XFS_DQTYPE_BIGTIME) {
> - if (!xfs_has_bigtime(dqp->q_mount))
> - return __this_address;
> - if (dqp->q_id == 0)
> - return __this_address;
> - }
> -
> return NULL;
> }
>
> --
> 2.43.0
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] xfs: fix unreachable BIGTIME check in dquot flush validation
2026-06-03 21:08 ` Darrick J. Wong
@ 2026-06-05 4:18 ` Allison Henderson
0 siblings, 0 replies; 4+ messages in thread
From: Allison Henderson @ 2026-06-05 4:18 UTC (permalink / raw)
To: Darrick J. Wong, Alexey Nepomnyashih
Cc: Carlos Maiolino, Dave Chinner, linux-xfs, linux-kernel,
lvc-project, stable
On Wed, 2026-06-03 at 14:08 -0700, Darrick J. Wong wrote:
> [fix some addresses]
>
> On Wed, Jun 03, 2026 at 08:41:47PM +0000, Alexey Nepomnyashih wrote:
> > The dqp->q_id == 0 check inside the XFS_DQTYPE_BIGTIME block is
> > unreachable because root dquots return successfully earlier. Reject root
> > dquots with XFS_DQTYPE_BIGTIME before that early return, preserving the
> > intended validation and removing the unreachable condition.
> >
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> >
> > Fixes: 4ea1ff3b4968 ("xfs: widen ondisk quota expiration timestamps to handle y2038+")
> > Cc: stable@vger.kernel.org # v5.10+
> > Signed-off-by: Alexey Nepomnyashih <sdl@nppct.ru>
Hi Alexey,
Looks good, thanks for catching this!
Reviewed-by: Allison Henderson <achender@kernel.org>
>
> Yeah, that looks like a screwup...
> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
>
> --D
>
> > ---
> > fs/xfs/xfs_dquot.c | 16 ++++++++--------
> > 1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
> > index 69e9bc588c8b..c311f61d9554 100644
> > --- a/fs/xfs/xfs_dquot.c
> > +++ b/fs/xfs/xfs_dquot.c
> > @@ -1216,6 +1216,14 @@ xfs_qm_dqflush_check(
> > type != XFS_DQTYPE_PROJ)
> > return __this_address;
> >
> > + /* bigtime flag should never be set on root dquots */
> > + if (dqp->q_type & XFS_DQTYPE_BIGTIME) {
> > + if (!xfs_has_bigtime(dqp->q_mount))
> > + return __this_address;
> > + if (dqp->q_id == 0)
> > + return __this_address;
> > + }
> > +
> > if (dqp->q_id == 0)
> > return NULL;
> >
> > @@ -1231,14 +1239,6 @@ xfs_qm_dqflush_check(
> > !dqp->q_rtb.timer)
> > return __this_address;
> >
> > - /* bigtime flag should never be set on root dquots */
> > - if (dqp->q_type & XFS_DQTYPE_BIGTIME) {
> > - if (!xfs_has_bigtime(dqp->q_mount))
> > - return __this_address;
> > - if (dqp->q_id == 0)
> > - return __this_address;
> > - }
> > -
> > return NULL;
> > }
> >
> > --
> > 2.43.0
> >
> >
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] xfs: fix unreachable BIGTIME check in dquot flush validation
2026-06-03 20:41 [PATCH] xfs: fix unreachable BIGTIME check in dquot flush validation Alexey Nepomnyashih
2026-06-03 21:08 ` Darrick J. Wong
@ 2026-06-09 7:26 ` Carlos Maiolino
1 sibling, 0 replies; 4+ messages in thread
From: Carlos Maiolino @ 2026-06-09 7:26 UTC (permalink / raw)
To: Alexey Nepomnyashih
Cc: Darrick J. Wong, Allison Collins, Dave Chinner, linux-xfs,
linux-kernel, lvc-project, stable
On Wed, 03 Jun 2026 20:41:47 +0000, Alexey Nepomnyashih wrote:
> The dqp->q_id == 0 check inside the XFS_DQTYPE_BIGTIME block is
> unreachable because root dquots return successfully earlier. Reject root
> dquots with XFS_DQTYPE_BIGTIME before that early return, preserving the
> intended validation and removing the unreachable condition.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> [...]
Applied to for-next, thanks!
[1/1] xfs: fix unreachable BIGTIME check in dquot flush validation
commit: 03866d130ed33ab68cc7faaf4bf2c4abef96d42e
Best regards,
--
Carlos Maiolino <cem@kernel.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2026-06-03 20:41 [PATCH] xfs: fix unreachable BIGTIME check in dquot flush validation Alexey Nepomnyashih
2026-06-03 21:08 ` Darrick J. Wong
2026-06-05 4:18 ` Allison Henderson
2026-06-09 7:26 ` Carlos Maiolino
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