From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH 07/10] libxfs: refactor buffer item release code
Date: Mon, 22 Apr 2019 14:35:29 -0700 [thread overview]
Message-ID: <20190422213529.GD4676@magnolia> (raw)
In-Reply-To: <e964dcb8-5a9d-26bf-e5ac-7489c9f259a1@sandeen.net>
On Mon, Apr 22, 2019 at 04:26:58PM -0500, Eric Sandeen wrote:
> On 4/22/19 10:45 AM, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> >
> > Refactor the buffer item release code into a helper, which we will use
> > in subsequent patches to make the buffer log item lifetime match the
> > kernel equivalents.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> > libxfs/trans.c | 14 +++++++++++---
> > 1 file changed, 11 insertions(+), 3 deletions(-)
> >
> >
> > diff --git a/libxfs/trans.c b/libxfs/trans.c
> > index 9de77c8b..629501f8 100644
> > --- a/libxfs/trans.c
> > +++ b/libxfs/trans.c
> > @@ -505,6 +505,16 @@ libxfs_trans_ordered_buf(
> > return ret;
> > }
> >
> > +static void
> > +xfs_buf_item_put(
> > + struct xfs_buf_log_item *bip)
> > +{
> > + struct xfs_buf *bp = bip->bli_buf;
> > +
> > + bp->b_log_item = NULL;
> > + kmem_zone_free(xfs_buf_item_zone, bip);
> > +}
> > +
> > void
> > libxfs_trans_brelse(
> > xfs_trans_t *tp,
> > @@ -846,7 +856,6 @@ buf_item_done(
> >
> > bp = bip->bli_buf;
> > ASSERT(bp != NULL);
> > - bp->b_log_item = NULL; /* remove log item */
> > bp->b_transp = NULL; /* remove xact ptr */
> >
> > hold = (bip->bli_flags & XFS_BLI_HOLD);
> > @@ -861,8 +870,7 @@ buf_item_done(
> > bip->bli_flags &= ~XFS_BLI_HOLD;
> > else
> > libxfs_putbuf(bp);
> > - /* release the buf item */
> > - kmem_zone_free(xfs_buf_item_zone, bip);
> > + xfs_buf_item_put(bip);
>
> In xfs_buf_item_put(), we reach back up from bip to bip->bli_buf, which is
> the bp. This is after we did a libxfs_putbuf(bp) on that bp. Is there not
> a chance of use after free here? Enough puts and a shaker can run, right?
I think you're right, the xfs_buf_item_put should come before the
libxfs_putbuf.
--D
> > }
> >
> > static void
> >
next prev parent reply other threads:[~2019-04-22 21:35 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-22 15:44 [PATCH v3 00/10] xfsprogs-5.0: fix various problems Darrick J. Wong
2019-04-22 15:44 ` [PATCH 01/10] scrub: fix Makefile targets which depend on builddefs Darrick J. Wong
2019-04-22 18:27 ` Eric Sandeen
2019-04-22 18:28 ` Bill O'Donnell
2019-04-22 15:45 ` [PATCH 02/10] xfs_info: use findmnt to handle mounted block devices Darrick J. Wong
2019-04-22 18:35 ` Eric Sandeen
2019-04-22 19:27 ` Bill O'Donnell
2019-04-22 15:45 ` [PATCH 03/10] xfs_repair: correctly account for free space btree shrinks when fixing freelist Darrick J. Wong
2019-04-22 19:24 ` Eric Sandeen
2019-04-22 19:36 ` Bill O'Donnell
2019-04-22 15:45 ` [PATCH 04/10] libxfs: retain ifork_ops when flushing inode Darrick J. Wong
2019-04-22 19:40 ` Bill O'Donnell
2019-04-22 19:45 ` Eric Sandeen
2019-10-02 6:00 ` Arkadiusz Miśkiewicz
2019-04-22 15:45 ` [PATCH 05/10] libxfs: drop the ifork_ops parameter from _inode_verify_forks Darrick J. Wong
2019-04-22 19:43 ` Bill O'Donnell
2019-04-22 20:49 ` Eric Sandeen
2019-04-22 15:45 ` [PATCH 06/10] misc: fix strncpy length complaints Darrick J. Wong
2019-04-22 20:48 ` Eric Sandeen
2019-04-22 20:57 ` Darrick J. Wong
2019-04-22 21:04 ` Eric Sandeen
2019-04-22 21:07 ` Eric Sandeen
2019-04-23 15:07 ` Bill O'Donnell
2019-04-22 15:45 ` [PATCH 07/10] libxfs: refactor buffer item release code Darrick J. Wong
2019-04-22 21:26 ` Eric Sandeen
2019-04-22 21:35 ` Darrick J. Wong [this message]
2019-04-22 21:40 ` Eric Sandeen
2019-04-23 20:51 ` [PATCH v2 " Darrick J. Wong
2019-04-23 20:56 ` Bill O'Donnell
2019-04-22 15:45 ` [PATCH 08/10] libxfs: don't touch buffer log item pointer when flushing inode log item Darrick J. Wong
2019-04-23 17:56 ` Eric Sandeen
2019-04-23 20:52 ` Bill O'Donnell
2019-04-22 15:45 ` [PATCH 09/10] libxfs: fix buffer log item lifetime weirdness Darrick J. Wong
2019-04-23 21:15 ` Bill O'Donnell
2019-04-22 15:45 ` [PATCH 10/10] libxfs: shorten inode item lifetime Darrick J. Wong
2019-04-23 21:22 ` Bill O'Donnell
2019-04-23 21:04 ` [PATCH 11/10] libfrog: fix memory leak in bitmap_free Darrick J. Wong
2019-04-23 21:23 ` Bill O'Donnell
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