The patch titled Subject: mm,oom_reaper: avoid run queue_oom_reaper if task is not oom has been added to the -mm mm-hotfixes-unstable branch. Its filename is mmoom_reaper-avoid-run-queue_oom_reaper-if-task-is-not-oom.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: gaoxu gaoxu2@hihonor.com Subject: mm,oom_reaper: avoid run queue_oom_reaper if task is not oom Date: Wed, 22 Nov 2023 12:46:44 +0000

queue_oom_reaper() tests and sets tsk->signal->oom_mm->flags. However, it is necessary to check if 'tsk' is an OOM victim before executing 'queue_oom_reaper' because the variable may be NULL.

We encountered such an issue, and the log is as follows: [3701:11_see]Out of memory: Killed process 3154 (system_server) total-vm:23662044kB, anon-rss:0kB, file-rss:0kB, shmem-rss:0kB, UID:1000 pgtables:4056kB oom_score_adj:-900 [3701:11_see][RB/E]rb_sreason_str_set: sreason_str set null_pointer [3701:11_see][RB/E]rb_sreason_str_set: sreason_str set unknown_addr [3701:11_see]Unable to handle kernel NULL pointer dereference at virtual address 0000000000000328 [3701:11_see]user pgtable: 4k pages, 39-bit VAs, pgdp=3D00000000821de000 [3701:11_see][0000000000000328] pgd=3D0000000000000000, p4d=3D0000000000000000,pud=3D0000000000000000 [3701:11_see]tracing off [3701:11_see]Internal error: Oops: 96000005 [#1] PREEMPT SMP [3701:11_see]Call trace: [3701:11_see] queue_oom_reaper+0x30/0x170 [3701:11_see] __oom_kill_process+0x590/0x860 [3701:11_see] oom_kill_process+0x140/0x274 [3701:11_see] out_of_memory+0x2f4/0x54c [3701:11_see] __alloc_pages_slowpath+0x5d8/0xaac [3701:11_see] __alloc_pages+0x774/0x800 [3701:11_see] wp_page_copy+0xc4/0x116c [3701:11_see] do_wp_page+0x4bc/0x6fc [3701:11_see] handle_pte_fault+0x98/0x2a8 [3701:11_see] __handle_mm_fault+0x368/0x700 [3701:11_see] do_handle_mm_fault+0x160/0x2cc [3701:11_see] do_page_fault+0x3e0/0x818 [3701:11_see] do_mem_abort+0x68/0x17c [3701:11_see] el0_da+0x3c/0xa0 [3701:11_see] el0t_64_sync_handler+0xc4/0xec [3701:11_see] el0t_64_sync+0x1b4/0x1b8 [3701:11_see]tracing off

Link: https://lkml.kernel.org/r/400d13bddb524ef6af37cb2220808c75@hihonor.com Signed-off-by: Gao Xu gaoxu2@hihonor.com Cc: Suren Baghdasaryan surenb@google.com Cc: Michal Hocko mhocko@suse.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/oom_kill.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/oom_kill.c~mmoom_reaper-avoid-run-queue_oom_reaper-if-task-is-not-oom +++ a/mm/oom_kill.c @@ -984,7 +984,7 @@ static void __oom_kill_process(struct ta } rcu_read_unlock();

- if (can_oom_reap) + if (can_oom_reap && tsk_is_oom_victim(victim)) queue_oom_reaper(victim);

mmdrop(mm); _

Patches currently in -mm which might be from gaoxu2@hihonor.com are

mmoom_reaper-avoid-run-queue_oom_reaper-if-task-is-not-oom.patch