From 08a98c345f627b8c90eb878f78b1b13dd75c1547 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Mon, 6 Nov 2023 23:34:06 +0000 Subject: [PATCH] mm/damon/sysfs: check error from damon_sysfs_update_target() commit b4936b544b08ed44949055b92bd25f77759ebafc upstream. 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 Cc: [5.19+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- 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 a76a878..dbf5e4d 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -2241,8 +2241,10 @@ 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); -- 2.7.4