Subject: FAILED: patch "[PATCH] xfs: don't let memory failures leak blocks and kill repairs" failed to apply to 6.12-stable tree
To: djwong@kernel.org,cem@kernel.org,hch@lst.de
Cc: <stable@vger.kernel.org>
From: <gregkh@linuxfoundation.org>
Date: Tue, 29 Sep 2026 13:58:28 +0200
Message-ID: <2026092928-handstand-epidermal-33bb@gregkh>
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The patch below does not apply to the 6.12-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 <stable@vger.kernel.org>.

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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x ab1c416d2377cdc16123ef521aac4da1c468c3d4
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026092928-handstand-epidermal-33bb@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:


thanks,

greg k-h

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

From ab1c416d2377cdc16123ef521aac4da1c468c3d4 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Mon, 14 Sep 2026 22:37:52 -0700
Subject: [PATCH] xfs: don't let memory failures leak blocks and kill repairs

LOLLM complains that a memory allocation failure in
xrep_newbt_add_blocks results in online repair leaking blocks that were
previously allocated to write a new btree, but the problem is worse than
that -- a limitation of the codebase is that the callers cannot undo the
transaction /and/ return the error -- either you undo all changes and
commit the transaction, or you error out and the filesystem goes down.

However, the new btree space reservation object isn't that big (~48
bytes).  Let's just do a NOFAIL allocation and the problem goes away.

Cc: stable@vger.kernel.org # v6.8
Fixes: be408417630427 ("xfs: implement block reservation accounting for btrees we're staging")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Assisted-by: LOLLM # finding obvious bugs
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

diff --git a/fs/xfs/scrub/newbt.c b/fs/xfs/scrub/newbt.c
index c82f4631fd9c..584076b2a6ee 100644
--- a/fs/xfs/scrub/newbt.c
+++ b/fs/xfs/scrub/newbt.c
@@ -193,9 +193,11 @@ xrep_newbt_add_blocks(
 	struct xrep_newbt_resv		*resv;
 	int				error;
 
-	resv = kmalloc_obj(struct xrep_newbt_resv, XCHK_GFP_FLAGS);
-	if (!resv)
-		return -ENOMEM;
+	/*
+	 * We have no way to clean up the allocated space *and* return an
+	 * ENOMEM if we fail to allocate this control structure.
+	 */
+	resv = kmalloc_obj(struct xrep_newbt_resv, GFP_KERNEL | __GFP_NOFAIL);
 
 	INIT_LIST_HEAD(&resv->list);
 	resv->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);