| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.19 051/192] sched/debug: fix dentry leak in update_sched_domain_debugfs | Date | Tue, 13 Sep 2022 16:02:37 +0200 |
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c2e406596571659451f4b95e37ddfd5a8ef1d0dc upstream.
Kuyo reports that the pattern of using debugfs_remove(debugfs_lookup()) leaks a dentry and with a hotplug stress test, the machine eventually runs out of memory.
Fix this up by using the newly created debugfs_lookup_and_remove() call instead which properly handles the dentry reference counting logic.
Cc: Major Chen <major.chen@samsung.com> Cc: stable <stable@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Reported-by: Kuyo Chang <kuyo.chang@mediatek.com> Tested-by: Kuyo Chang <kuyo.chang@mediatek.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220902123107.109274-2-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- kernel/sched/debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -416,7 +416,7 @@ void update_sched_domain_debugfs(void) char buf[32]; snprintf(buf, sizeof(buf), "cpu%d", cpu); - debugfs_remove(debugfs_lookup(buf, sd_dentry)); + debugfs_lookup_and_remove(buf, sd_dentry); d_cpu = debugfs_create_dir(buf, sd_dentry); i = 0;
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