rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=5121, q=19 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294966715-4294956213), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g5121 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:26256 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5400 [inline] __schedule+0x177f/0x49a0 kernel/sched/core.c:6727 __schedule_loop kernel/sched/core.c:6802 [inline] schedule+0x149/0x260 kernel/sched/core.c:6817 schedule_timeout+0x1bd/0x310 kernel/time/timer.c:2183 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:1663 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1862 kthread+0x2ef/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 5102 Comm: syz-executor427 Not tainted 6.8.0-rc6-syzkaller-00194-g17ba56605bfd #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 RIP: 0010:lock_acquire+0x25a/0x530 kernel/locking/lockdep.c:5758 Code: 2b 00 74 08 4c 89 f7 e8 c4 24 81 00 f6 44 24 61 02 0f 85 8e 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc900042dfae0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff9200085bf68 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: ffffffff8baac7e0 RDI: ffffffff8bfd9a20 RBP: ffffc900042dfc38 R08: ffffffff92c58457 R09: 1ffffffff258b08a R10: dffffc0000000000 R11: fffffbfff258b08b R12: 1ffff9200085bf64 R13: dffffc0000000000 R14: ffffc900042dfb40 R15: 0000000000000246 FS: 0000555555c663c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fab844ef4c0 CR3: 0000000023df8000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __might_fault+0xc5/0x120 mm/memory.c:6080 rseq_get_rseq_cs kernel/rseq.c:161 [inline] rseq_ip_fixup kernel/rseq.c:281 [inline] __rseq_handle_notify_resume+0x11f/0x1490 kernel/rseq.c:329 rseq_handle_notify_resume include/linux/rseq.h:38 [inline] rseq_signal_deliver include/linux/rseq.h:47 [inline] setup_rt_frame arch/x86/kernel/signal.c:212 [inline] handle_signal arch/x86/kernel/signal.c:267 [inline] arch_do_signal_or_restart+0x3aa/0x860 arch/x86/kernel/signal.c:312 exit_to_user_mode_loop kernel/entry/common.c:105 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline] syscall_exit_to_user_mode+0xc8/0x360 kernel/entry/common.c:212 do_syscall_64+0x108/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7fab844d7e79 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff2c46de08 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fab844d7e79 RDX: 000000002006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000555555c66370 R13: 0000000000000000 R14: 00007fff2c46de80 R15: 00007fff2c46de70