FAILED: patch "[PATCH] xfs: save ailp before dropping the AIL lock in push callbacks" failed to apply to 5.10-stable tree

PATCH New [email protected] 2 participants 2 messages Mar 30 – Apr 2

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Stable branch XFS filesystem

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[email protected]

author maintainer

2026-03-30 09:57 UTC #0 lore raw

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 394d70b86fae9fe865e7e6d9540b7696f73aa9b6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026033014-speak-undiluted-7499@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 394d70b86fae9fe865e7e6d9540b7696f73aa9b6 Mon Sep 17 00:00:00 2001
From: Yuto Ohnuki <[email protected]>
Date: Tue, 10 Mar 2026 18:38:39 +0000
Subject: [PATCH] xfs: save ailp before dropping the AIL lock in push callbacks

In xfs_inode_item_push() and xfs_qm_dquot_logitem_push(), the AIL lock is dropped to perform buffer IO. Once the cluster buffer no longer protects the log item from reclaim, the log item may be freed by background reclaim or the dquot shrinker. The subsequent spin_lock() call dereferences lip->li_ailp, which is a use-after-free.

Fix this by saving the ailp pointer in a local variable while the AIL lock is held and the log item is guaranteed to be valid.

Reported-by [email protected]

Closes https://syzkaller.appspot.com/bug?extid=652af2b3c5569c4ab63c

Fixes 90c60e164012 ("xfs: xfs_iflush() is no longer necessary")

Cc [email protected] # v5.9

Reviewed-by Darrick J. Wong <[email protected]>

Reviewed-by Dave Chinner <[email protected]>

Signed-off-by Yuto Ohnuki <[email protected]>

Signed-off-by Carlos Maiolino <[email protected]>

fs/xfs/xfs_dquot_item.c +7 -2

index 491e2a7053a3..65a0e69c3d08 100644
@@ -125,6 +125,7 @@ xfs_qm_dquot_logitem_push(
 	struct xfs_dq_logitem	*qlip = DQUOT_ITEM(lip);
 	struct xfs_dquot	*dqp = qlip->qli_dquot;
 	struct xfs_buf		*bp;
+	struct xfs_ail		*ailp = lip->li_ailp;
 	uint			rval = XFS_ITEM_SUCCESS;
 	int			error;

@@ -153,7 +154,7 @@ xfs_qm_dquot_logitem_push(
 		goto out_unlock;
 	}
 
-	spin_unlock(&lip->li_ailp->ail_lock);
+	spin_unlock(&ailp->ail_lock);
 
 	error = xfs_dquot_use_attached_buf(dqp, &bp);
 	if (error == -EAGAIN) {

@@ -172,9 +173,13 @@ xfs_qm_dquot_logitem_push(
 			rval = XFS_ITEM_FLUSHING;
 	}
 	xfs_buf_relse(bp);
+	/*
+	 * The buffer no longer protects the log item from reclaim, so
+	 * do not reference lip after this point.
+	 */
 
 out_relock_ail:
-	spin_lock(&lip->li_ailp->ail_lock);
+	spin_lock(&ailp->ail_lock);
 out_unlock:
 	mutex_unlock(&dqp->q_qlock);
 	return rval;

fs/xfs/xfs_inode_item.c +7 -2

index 8913036b8024..4ae81eed0442 100644
@@ -746,6 +746,7 @@ xfs_inode_item_push(
 	struct xfs_inode_log_item *iip = INODE_ITEM(lip);
 	struct xfs_inode	*ip = iip->ili_inode;
 	struct xfs_buf		*bp = lip->li_buf;
+	struct xfs_ail		*ailp = lip->li_ailp;
 	uint			rval = XFS_ITEM_SUCCESS;
 	int			error;

@@ -771,7 +772,7 @@ xfs_inode_item_push(
 	if (!xfs_buf_trylock(bp))
 		return XFS_ITEM_LOCKED;
 
-	spin_unlock(&lip->li_ailp->ail_lock);
+	spin_unlock(&ailp->ail_lock);
 
 	/*
 	 * We need to hold a reference for flushing the cluster buffer as it may

@@ -795,7 +796,11 @@ xfs_inode_item_push(
 		rval = XFS_ITEM_LOCKED;
 	}
 
-	spin_lock(&lip->li_ailp->ail_lock);
+	/*
+	 * The buffer no longer protects the log item from reclaim, so
+	 * do not reference lip after this point.
+	 */
+	spin_lock(&ailp->ail_lock);
 	return rval;
 }

Sasha Levin

maintainer

2026-04-02 09:44 UTC #1 lore raw

PATCH 1/1 xfs: save ailp before dropping the AIL lock in push callbacks

From: Yuto Ohnuki <[email protected]>

[ Upstream commit 394d70b86fae9fe865e7e6d9540b7696f73aa9b6 ]