From: Gao Xiang <hsiangkao@linux.alibaba.com>
Date: Wed, 27 Nov 2024 08:52:36 +0000 (+0800)
Subject: erofs: fix PSI memstall accounting
X-Git-Tag: v6.12.7~146
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0653fa6ee045965f9cae2e9cebcd99ef6b4ecd62;p=thirdparty%2Fkernel%2Fstable.git

erofs: fix PSI memstall accounting

[ Upstream commit 1a2180f6859c73c674809f9f82e36c94084682ba ]

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>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241127085236.3538334-1-hsiangkao@linux.alibaba.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index a569ff9dfd044..1a00f061798a3 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1679,9 +1679,9 @@ drain_io:
 			erofs_fscache_submit_bio(bio);
 		else
 			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.