rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=82149, q=478) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295014723-4295004221), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g82149 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:28696 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4965 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6246 schedule+0xd2/0x260 kernel/sched/core.c:6319 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1966 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2139 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 21982 Comm: syz-executor.0 Not tainted 5.15.0-rc5-next-20211015-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:458 print_other_cpu_stall kernel/rcu/tree_stall.h:563 [inline] check_cpu_stall kernel/rcu/tree_stall.h:706 [inline] rcu_pending kernel/rcu/tree.c:3889 [inline] rcu_sched_clock_irq+0x2125/0x2200 kernel/rcu/tree.c:2608 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:stack_trace_save+0xa3/0xc0 kernel/stacktrace.c:124 Code: 30 00 00 00 00 65 48 8b 14 25 40 70 02 00 e8 44 ae c6 ff 8b 44 24 30 48 c7 03 00 00 00 00 c7 43 08 00 00 00 00 48 8b 4c 24 78 <65> 48 2b 0c 25 28 00 00 00 75 06 48 83 ec 80 5b c3 e8 67 d2 e7 07 RSP: 0018:ffffc90002f8f5f0 EFLAGS: 00000296 RAX: 000000000000000b RBX: fffff520005f1ebe RCX: d576414ba41adf00 RDX: 1ffff1101387c88b RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000cc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000cc0 R13: 0000000000000020 R14: dffffc0000000000 R15: ffff888077976a00 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] ____kasan_kmalloc mm/kasan/common.c:472 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:522 kmalloc include/linux/slab.h:590 [inline] tty_alloc_file drivers/tty/tty_io.c:187 [inline] tty_open+0x140/0x1000 drivers/tty/tty_io.c:2140 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4c8/0x11d0 fs/open.c:822 do_open fs/namei.c:3428 [inline] path_openat+0x1c9a/0x2740 fs/namei.c:3561 do_filp_open+0x1aa/0x400 fs/namei.c:3588 do_sys_openat2+0x16d/0x4d0 fs/open.c:1200 do_sys_open fs/open.c:1216 [inline] __do_sys_openat fs/open.c:1232 [inline] __se_sys_openat fs/open.c:1227 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1227 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f3fd038ca39 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3fcd902188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f3fd048ff60 RCX: 00007f3fd038ca39 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f3fd03e6c5f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffb01f071f R14: 00007f3fcd902300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 30 00 xor %al,(%rax) 2: 00 00 add %al,(%rax) 4: 00 65 48 add %ah,0x48(%rbp) 7: 8b 14 25 40 70 02 00 mov 0x27040,%edx e: e8 44 ae c6 ff callq 0xffc6ae57 13: 8b 44 24 30 mov 0x30(%rsp),%eax 17: 48 c7 03 00 00 00 00 movq $0x0,(%rbx) 1e: c7 43 08 00 00 00 00 movl $0x0,0x8(%rbx) 25: 48 8b 4c 24 78 mov 0x78(%rsp),%rcx * 2a: 65 48 2b 0c 25 28 00 sub %gs:0x28,%rcx <-- trapping instruction 31: 00 00 33: 75 06 jne 0x3b 35: 48 83 ec 80 sub $0xffffffffffffff80,%rsp 39: 5b pop %rbx 3a: c3 retq 3b: e8 67 d2 e7 07 callq 0x7e7d2a7