diff options
| author | SeongJae Park | 2022-06-04 19:50:51 +0000 |
|---|---|---|
| committer | akpm | 2022-06-16 19:11:30 -0700 |
| commit | 2949282938135ab734c3829495ae393523ceb702 (patch) | |
| tree | e0f683505497ac250591c65d7a60f7a681eb649a /mm/damon | |
| parent | d25c83c6606ffc3abdf0868136ad3399f648ad70 (diff) | |
mm/damon/reclaim: schedule 'damon_reclaim_timer' only after 'system_wq' is initialized
Commit 059342d1dd4e ("mm/damon/reclaim: fix the timer always stays
active") made DAMON_RECLAIM's 'enabled' parameter store callback,
'enabled_store()', to schedule 'damon_reclaim_timer'. The scheduling uses
'system_wq', which is initialized in 'workqueue_init_early()'. As kernel
parameters parsing function ('parse_args()') is called before
'workqueue_init_early()', 'enabled_store()' can be executed before
'workqueue_init_early()' and end up accessing the uninitialized
'system_wq'. As a result, the booting hang[1]. This commit fixes the
issue by checking if the initialization is done before scheduling the
timer.
[1] https://lkml.kernel.org/20220604192222.1488-1-sj@kernel.org/
Link: https://lkml.kernel.org/r/20220604195051.1589-1-sj@kernel.org
Fixes: 059342d1dd4e ("mm/damon/reclaim: fix the timer always stays active")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Greg White <gwhite@kupulau.com>
Cc: Hailong Tu <tuhailong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/damon')
| -rw-r--r-- | mm/damon/reclaim.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c index 8efbfb24f3a1..4b07c29effe9 100644 --- a/mm/damon/reclaim.c +++ b/mm/damon/reclaim.c @@ -374,6 +374,8 @@ static void damon_reclaim_timer_fn(struct work_struct *work) } static DECLARE_DELAYED_WORK(damon_reclaim_timer, damon_reclaim_timer_fn); +static bool damon_reclaim_initialized; + static int enabled_store(const char *val, const struct kernel_param *kp) { @@ -382,6 +384,10 @@ static int enabled_store(const char *val, if (rc < 0) return rc; + /* system_wq might not initialized yet */ + if (!damon_reclaim_initialized) + return rc; + if (enabled) schedule_delayed_work(&damon_reclaim_timer, 0); @@ -449,6 +455,8 @@ static int __init damon_reclaim_init(void) damon_add_target(ctx, target); schedule_delayed_work(&damon_reclaim_timer, 0); + + damon_reclaim_initialized = true; return 0; } |