Re: [syzbot] [mm?] WARNING in copy_process

[Hillf Danton <hdanton@sina.com>]

> Date: Wed, 27 Aug 2025 16:15:31 -0700	[thread overview]
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    7fa4d8dc380f Add linux-next specific files for 20250821
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1036def0580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ae76068823a236b3
> dashboard link: https://syzkaller.appspot.com/bug?extid=69c74d38464686431506
> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13595c62580000

#syz test

--- x/mm/oom_kill.c
+++ y/mm/oom_kill.c
@@ -997,6 +997,8 @@ static void __oom_kill_process(struct ta
 		queue_oom_reaper(victim);
 
 	mmdrop(mm);
+	write_lock_irq(&tasklist_lock);
+	write_unlock_irq(&tasklist_lock);
 	put_task_struct(victim);
 }
 
@@ -1031,6 +1033,8 @@ static void oom_kill_process(struct oom_
 		mark_oom_victim(victim);
 		queue_oom_reaper(victim);
 		task_unlock(victim);
+		write_lock_irq(&tasklist_lock);
+		write_unlock_irq(&tasklist_lock);
 		put_task_struct(victim);
 		return;
 	}
--