From b4936b544b08ed44949055b92bd25f77759ebafc Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@kernel.org>
Date: Mon, 6 Nov 2023 23:34:06 +0000
Subject: [PATCH] mm/damon/sysfs: check error from damon_sysfs_update_target()
Patch series "mm/damon/sysfs: fix unhandled return values".
Some of DAMON sysfs interface code is not handling return values from some
functions. As a result, confusing user input handling or NULL-dereference
is possible. Check those properly.
This patch (of 3):
damon_sysfs_update_target() returns error code for failures, but its
caller, damon_sysfs_set_targets() is ignoring that. The update function
seems making no critical change in case of such failures, but the behavior
will look like DAMON sysfs is silently ignoring or only partially
accepting the user input. Fix it.
Link: https://lkml.kernel.org/r/20231106233408.51159-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231106233408.51159-2-sj@kernel.org
Fixes: 19467a950b49 ("mm/damon/sysfs: remove requested targets when online-commit inputs")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [5.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/damon/sysfs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 1dfa96d4de99b..7472404456aa8 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1203,8 +1203,10 @@ static int damon_sysfs_set_targets(struct damon_ctx *ctx,
damon_for_each_target_safe(t, next, ctx) {
if (i < sysfs_targets->nr) {
- damon_sysfs_update_target(t, ctx,
+ err = damon_sysfs_update_target(t, ctx,
sysfs_targets->targets_arr[i]);
+ if (err)
+ return err;
} else {
if (damon_target_has_pid(ctx))
put_pid(t->pid);