rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=83f/1/0x4000000000000000 softirq=75863/75864 fqs=0 (t=17963 jiffies g=98533 q=2385) rcu: rcu_preempt kthread starved for 17963 jiffies! g98533 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:I stack:26288 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xbfd/0x11d0 kernel/sched/core.c:6287 schedule+0x14b/0x210 kernel/sched/core.c:6366 schedule_timeout+0x1aa/0x2f0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1957 rcu_gp_kthread+0xa5/0x340 kernel/rcu/tree.c:2130 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10393 Comm: kworker/0:9 Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: rcu_gp wait_rcu_exp_gp RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:30 [inline] RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:52 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:173 [inline] RIP: 0010:unwind_next_frame+0x501/0x1fa0 arch/x86/kernel/unwind_orc.c:443 Code: 89 c1 48 c1 f9 02 48 c1 e8 3f 48 01 c8 48 83 e0 fe 49 8d 1c 47 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 <84> c0 75 27 48 63 03 48 01 d8 48 8d 4b 04 4c 39 e0 4c 0f 46 f9 48 RSP: 0018:ffffc900000072e0 EFLAGS: 00000a03 RAX: 0000000000000000 RBX: ffffffff8de9477c RCX: dffffc0000000000 RDX: ffffffff8e518f6a RSI: ffffffff814dd51f RDI: 0000000000000001 RBP: ffffffff8de94778 R08: 0000000000000009 R09: ffffc90000007470 R10: fffff52000000e80 R11: 0000000000000000 R12: ffffffff814dd51e R13: ffffffff8de94784 R14: ffffffff8de94778 R15: ffffffff8de94778 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c019034000 CR3: 000000002877c000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0xb2/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x104/0x1e0 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x3d/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0x10d/0x150 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1628 [inline] slab_free_freelist_hook+0x1e8/0x2a0 mm/slub.c:1653 slab_free mm/slub.c:3213 [inline] kfree+0xcf/0x2e0 mm/slub.c:4267 skb_free_head net/core/skbuff.c:654 [inline] skb_release_data+0x3c3/0x4f0 net/core/skbuff.c:676 skb_release_all net/core/skbuff.c:741 [inline] __kfree_skb+0x56/0x1d0 net/core/skbuff.c:755 ip6_mc_input+0x8d0/0xd40 net/ipv6/ip6_input.c:569 __netif_receive_skb_one_core net/core/dev.c:5436 [inline] __netif_receive_skb+0x1d1/0x500 net/core/dev.c:5550 process_backlog+0x4d8/0x940 net/core/dev.c:6427 __napi_poll+0xba/0x4f0 net/core/dev.c:6982 napi_poll net/core/dev.c:7049 [inline] net_rx_action+0x62c/0xf30 net/core/dev.c:7136 __do_softirq+0x372/0x783 kernel/softirq.c:558 __irq_exit_rcu+0xcf/0x150 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:console_trylock_spinning+0x31b/0x3a0 kernel/printk/printk.c:1885 Code: 08 4d 85 ed 74 91 e8 f4 36 1a 00 fb 31 db eb 41 e8 ea 36 1a 00 e8 15 ff 7b 08 4d 85 ed 74 d1 e8 db 36 1a 00 fb bb 01 00 00 00 <48> c7 c7 80 7e 7f 8c 31 f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 RSP: 0018:ffffc900181178e0 EFLAGS: 00000293 RAX: ffffffff8166a5a5 RBX: 0000000000000001 RCX: ffff888030d91c80 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900181179b0 R08: ffffffff8166a562 R09: fffffbfff1bb700e R10: fffffbfff1bb700e R11: 0000000000000000 R12: 1ffff92003022f1c R13: 0000000000000200 R14: 0000000000000082 R15: dffffc0000000000 vprintk_emit+0xa1/0x140 kernel/printk/printk.c:2243 _printk+0xc0/0x108 kernel/printk/printk.c:2265 synchronize_rcu_expedited_wait kernel/rcu/tree_exp.h:525 [inline] rcu_exp_wait_wake kernel/rcu/tree_exp.h:584 [inline] rcu_exp_sel_wait_wake+0x88b/0x1a00 kernel/rcu/tree_exp.h:618 process_one_work+0x853/0x1140 kernel/workqueue.c:2297 worker_thread+0xac1/0x1320 kernel/workqueue.c:2444 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 NMI backtrace for cpu 1 CPU: 1 PID: 5663 Comm: syz-executor.4 Not tainted 5.14.0-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+0x1ae/0x29f lib/dump_stack.c:105 nmi_cpu_backtrace+0x405/0x430 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x191/0x2f0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x22d/0x390 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq+0x1dc2/0x2b40 kernel/rcu/tree.c:2599 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0xaa5/0xd60 kernel/smp.c:969 Code: df 75 12 e8 ad 9d 0b 00 eb 50 66 66 2e 0f 1f 84 00 00 00 00 00 f3 90 42 0f b6 04 3b 84 c0 75 11 41 f7 45 00 01 00 00 00 74 2b 86 9d 0b 00 eb e4 44 89 e9 80 e1 07 80 c1 03 38 c1 7c e2 4c 89 RSP: 0018:ffffc9000235fb00 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 1ffff11017387055 RCX: 0000000000040000 RDX: ffffc90014c75000 RSI: 00000000000072a7 RDI: 00000000000072a8 RBP: ffffc9000235fc30 R08: ffffffff81753ebe R09: ffffffff842c1850 R10: 0000000000000009 R11: ffff88808de20000 R12: 0000000000000000 R13: ffff8880b9c382a8 R14: 1ffff110173a64a0 R15: dffffc0000000000 clock_was_set+0x83e/0x910 kernel/time/hrtimer.c:974 do_settimeofday64+0x80e/0x950 kernel/time/timekeeping.c:1327 __do_sys_clock_settime kernel/time/posix-timers.c:1079 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1067 [inline] __x64_sys_clock_settime+0x1f4/0x230 kernel/time/posix-timers.c:1067 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 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:00007fa6a20df188 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000000 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffe2d7308af R14: 00007fa6a20df300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 89 c1 mov %eax,%ecx 2: 48 c1 f9 02 sar $0x2,%rcx 6: 48 c1 e8 3f shr $0x3f,%rax a: 48 01 c8 add %rcx,%rax d: 48 83 e0 fe and $0xfffffffffffffffe,%rax 11: 49 8d 1c 47 lea (%r15,%rax,2),%rbx 15: 48 89 d8 mov %rbx,%rax 18: 48 c1 e8 03 shr $0x3,%rax 1c: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 23: fc ff df 26: 0f b6 04 08 movzbl (%rax,%rcx,1),%eax * 2a: 84 c0 test %al,%al <-- trapping instruction 2c: 75 27 jne 0x55 2e: 48 63 03 movslq (%rbx),%rax 31: 48 01 d8 add %rbx,%rax 34: 48 8d 4b 04 lea 0x4(%rbx),%rcx 38: 4c 39 e0 cmp %r12,%rax 3b: 4c 0f 46 f9 cmovbe %rcx,%r15 3f: 48 rex.W