Patch "erofs: fix PSI memstall accounting" has been added to the 6.1-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    erofs: fix PSI memstall accounting

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     erofs-fix-psi-memstall-accounting.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From stable+bounces-230584-greg=kroah.com@vger.kernel.org Fri Mar 27 05:34:18 2026
From: Gao Xiang <hsiangkao@linux.alibaba.com>
Date: Fri, 27 Mar 2026 12:33:59 +0800
Subject: erofs: fix PSI memstall accounting
To: stable@vger.kernel.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-erofs@lists.ozlabs.org, Gao Xiang <hsiangkao@linux.alibaba.com>, Max Kellermann <max.kellermann@ionos.com>, Chao Yu <chao@kernel.org>, Alexey Panov <apanov@astralinux.ru>
Message-ID: <20260327043359.1121251-1-hsiangkao@linux.alibaba.com>

From: Gao Xiang <hsiangkao@linux.alibaba.com>

commit 1a2180f6859c73c674809f9f82e36c94084682ba upstream.

Max Kellermann recently reported psi_group_cpu.tasks[NR_MEMSTALL] is
incorrect in the 6.11.9 kernel.

The root cause appears to be that, since the problematic commit, bio
can be NULL, causing psi_memstall_leave() to be skipped in
z_erofs_submit_queue().

Reported-by: Max Kellermann <max.kellermann@ionos.com>
Closes: https://lore.kernel.org/r/CAKPOu+8tvSowiJADW2RuKyofL_CSkm_SuyZA7ME5vMLWmL6pqw@mail.gmail.com
Fixes: 9e2f9d34dd12 ("erofs: handle overlapped pclusters out of crafted images properly")
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20241127085236.3538334-1-hsiangkao@linux.alibaba.com
Signed-off-by: Alexey Panov <apanov@astralinux.ru>
Link: https://lore.kernel.org/r/20250304110558.8315-3-apanov@astralinux.ru
Link: https://lore.kernel.org/r/20250304110558.8315-1-apanov@astralinux.ru
[ Gao Xiang: re-address the previous Alexey's backport. ]
CVE: CVE-2024-47736
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/erofs/zdata.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1574,11 +1574,10 @@ drain_io:
 			move_to_bypass_jobqueue(pcl, qtail, owned_head);
 	} while (owned_head != Z_EROFS_PCLUSTER_TAIL);
 
-	if (bio) {
+	if (bio)
 		submit_bio(bio);
-		if (memstall)
-			psi_memstall_leave(&pflags);
-	}
+	if (memstall)
+		psi_memstall_leave(&pflags);
 
 	/*
 	 * although background is preferred, no one is pending for submission.


Patches currently in stable-queue which might be from hsiangkao@linux.alibaba.com are

queue-6.1/erofs-fix-psi-memstall-accounting.patch
queue-6.1/erofs-add-gfp_noio-in-the-bio-completion-if-needed.patch
queue-6.1/erofs-handle-overlapped-pclusters-out-of-crafted-images-properly.patch
queue-6.1/erofs-fix-the-slab-out-of-bounds-in-drop_buffers.patch