From: Gao Xiang <hsiang...@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.kellerm...@ionos.com>
Closes: 
https://lore.kernel.org/r/cakpou+8tvsowijadw2rukyofl_cskm_suyza7me5vmlwml6...@mail.gmail.com
Fixes: 9e2f9d34dd12 ("erofs: handle overlapped pclusters out of crafted images 
properly")
Reviewed-by: Chao Yu <c...@kernel.org>
Signed-off-by: Gao Xiang <hsiang...@linux.alibaba.com>
Link: 
https://lore.kernel.org/r/20241127085236.3538334-1-hsiang...@linux.alibaba.com
Signed-off-by: Alexey Panov <apa...@astralinux.ru>
---
 fs/erofs/zdata.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index ac01c0ede7f7..d175b5d0a2f5 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1589,11 +1589,10 @@ static void z_erofs_submit_queue(struct 
z_erofs_decompress_frontend *f,
                        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.
-- 
2.39.5


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