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/mmoom_reaper-avoid-run-queue_oom_reaper-if-task-is-not-oom.patch
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@xxxxxxxxxxx>
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@xxxxxxxxxxx
Signed-off-by: Gao Xu <gaoxu2@xxxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxxx are
mmoom_reaper-avoid-run-queue_oom_reaper-if-task-is-not-oom.patch
