[PATCH] mm/smaps_rollup: return empty file for kthreads instead of ESRCH

From: "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>,
	Daniel Colascione <dancol@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Alexey Dobriyan <adobriyan@gmail.com>,
	linux-api@vger.kernel.org,
	"Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>
Subject: [PATCH] mm/smaps_rollup: return empty file for kthreads instead of ESRCH
Date: Wed, 13 Apr 2022 17:13:57 -0400	[thread overview]
Message-ID: <20220413211357.26938-1-alex_y_xu@yahoo.ca> (raw)
In-Reply-To: 20220413211357.26938-1-alex_y_xu.ref@yahoo.ca

This restores the behavior prior to 258f669e7e88 ("mm:
/proc/pid/smaps_rollup: convert to single value seq_file"), making it
once again consistent with maps and smaps, and allowing patterns like
awk '$1=="Anonymous:"{x+=$2}END{print x}' /proc/*/smaps_rollup to work.
Searching all Debian packages for "smaps_rollup" did not find any
programs which would be affected by this change.

Fixes: 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value seq_file")

Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
---
 fs/proc/task_mmu.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index f46060eb91b5..d7de4584a271 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -883,10 +883,8 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
 		return -ESRCH;
 
 	mm = priv->mm;
-	if (!mm || !mmget_not_zero(mm)) {
-		ret = -ESRCH;
+	if (!mm || !mmget_not_zero(mm))
 		goto out_put_task;
-	}
 
 	memset(&mss, 0, sizeof(mss));
 
-- 
2.35.2

