rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (2 ticks this GP) idle=8ef/1/0x4000000000000000 softirq=217041/217041 fqs=1 (t=12701 jiffies g=422301 q=4049) rcu: rcu_preempt kthread timer wakeup didn't happen for 12698 jiffies! g422301 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=196705 rcu: rcu_preempt kthread starved for 12699 jiffies! g422301 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28168 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1957 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 kthread+0x3e5/0x4d0 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 30548 Comm: kworker/u4:2 Not tainted 5.15.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc RIP: 0010:write_comp_data kernel/kcov.c:218 [inline] RIP: 0010:__sanitizer_cov_trace_cmp8+0x18/0x70 kernel/kcov.c:264 Code: 48 89 74 38 e8 4e 89 54 c8 20 48 89 10 c3 0f 1f 40 00 49 89 f8 bf 03 00 00 00 4c 8b 14 24 48 89 f1 65 48 8b 34 25 40 f0 01 00 53 f0 ff ff 84 c0 74 48 48 8b 86 48 15 00 00 8b b6 44 15 00 00 RSP: 0000:ffffc90000fd7da8 EFLAGS: 00000086 RAX: 0000000000000000 RBX: ffffffff8f0496e8 RCX: 0000000000020000 RDX: ffff88801f746280 RSI: ffff88801f746280 RDI: 0000000000000003 RBP: 0000000000000140 R08: 0000000000000140 R09: 0000000000000003 R10: ffffffff83d96338 R11: 0000000000086089 R12: ffffffffffffffff R13: 0000000000020000 R14: dffffc0000000000 R15: f9dcf0cdeec7767a FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb0bef80008 CR3: 000000001d339000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: _find_first_zero_bit+0x48/0xb0 lib/find_bit.c:100 find_first_zero_bit include/asm-generic/bitops/find.h:137 [inline] alloc_lock_chain kernel/locking/lockdep.c:3599 [inline] add_chain_cache kernel/locking/lockdep.c:3631 [inline] lookup_chain_cache_add kernel/locking/lockdep.c:3736 [inline] validate_chain kernel/locking/lockdep.c:3757 [inline] __lock_acquire+0x1ae5/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 stack_depot_save+0x1cd/0x4e0 lib/stackdepot.c:308 kasan_save_stack+0x32/0x40 mm/kasan/common.c:40 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xd1/0x110 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] __cache_free mm/slab.c:3445 [inline] kfree+0x10a/0x2c0 mm/slab.c:3803 skb_free_head net/core/skbuff.c:654 [inline] skb_release_data+0x65a/0x790 net/core/skbuff.c:676 skb_release_all net/core/skbuff.c:741 [inline] __kfree_skb net/core/skbuff.c:755 [inline] consume_skb net/core/skbuff.c:911 [inline] consume_skb+0xc2/0x160 net/core/skbuff.c:905 __dev_kfree_skb_any+0x6b/0x80 net/core/dev.c:3113 dev_consume_skb_any include/linux/netdevice.h:3997 [inline] napi_consume_skb+0x27b/0x340 net/core/skbuff.c:971 free_old_xmit_skbs+0xe4/0x270 drivers/net/virtio_net.c:1470 start_xmit+0x9bf/0x16e0 drivers/net/virtio_net.c:1695 __netdev_start_xmit include/linux/netdevice.h:4988 [inline] netdev_start_xmit include/linux/netdevice.h:5002 [inline] xmit_one net/core/dev.c:3576 [inline] dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3592 sch_direct_xmit+0x19f/0xbc0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3803 [inline] __dev_queue_xmit+0x1489/0x36e0 net/core/dev.c:4170 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip_finish_output2+0xf01/0x2140 net/ipv4/ip_output.c:221 __ip_finish_output net/ipv4/ip_output.c:299 [inline] __ip_finish_output+0x396/0x640 net/ipv4/ip_output.c:281 ip_finish_output+0x32/0x200 net/ipv4/ip_output.c:309 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x196/0x310 net/ipv4/ip_output.c:423 dst_output include/net/dst.h:450 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] __ip_queue_xmit+0x97e/0x1bb0 net/ipv4/ip_output.c:525 __tcp_transmit_skb+0x1883/0x38f0 net/ipv4/tcp_output.c:1405 tcp_transmit_skb net/ipv4/tcp_output.c:1423 [inline] tcp_write_xmit+0xdee/0x6050 net/ipv4/tcp_output.c:2690 tcp_send_loss_probe+0x542/0x890 net/ipv4/tcp_output.c:2812 tcp_write_timer_handler+0x5c3/0xad0 net/ipv4/tcp_timer.c:618 tcp_write_timer+0xa2/0x2b0 net/ipv4/tcp_timer.c:642 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 common_interrupt+0xa4/0xd0 arch/x86/kernel/irq.c:240 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629 RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:197 Code: 81 e1 00 01 00 00 65 48 8b 14 25 40 f0 01 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 64 15 00 00 85 c0 74 2b 8b 82 40 15 00 00 <83> f8 02 75 20 48 8b 8a 48 15 00 00 8b 92 44 15 00 00 48 8b 01 48 RSP: 0000:ffffc9000bacf368 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff8b95a1d0 RCX: 0000000000000000 RDX: ffff88801f746280 RSI: ffffffff815dc219 RDI: ffffc9000bacf540 RBP: ffffc9000bacf528 R08: 0000000000000001 R09: ffffc9000bacf53f R10: fffff52001759ea7 R11: 0000000000000000 R12: 0000000100013296 R13: 8000000100013296 R14: 0000000000000002 R15: ffffffff8b8f4730 desc_read+0x169/0x350 kernel/printk/printk_ringbuffer.c:480 desc_read_finalized_seq+0x81/0x1c0 kernel/printk/printk_ringbuffer.c:1752 prb_read kernel/printk/printk_ringbuffer.c:1820 [inline] _prb_read_valid+0x4ab/0x710 kernel/printk/printk_ringbuffer.c:1880 prb_read_valid+0x75/0xa0 kernel/printk/printk_ringbuffer.c:1929 console_unlock+0x1d6/0xb70 kernel/printk/printk.c:2653 do_con_write+0xc6c/0x1e40 drivers/tty/vt/vt.c:2965 con_put_char+0x70/0xa0 drivers/tty/vt/vt.c:3303 tty_put_char+0xb7/0x150 drivers/tty/tty_io.c:3173 do_output_char+0x155/0x850 drivers/tty/n_tty.c:485 __process_echoes+0x38e/0x9f0 drivers/tty/n_tty.c:736 flush_echoes drivers/tty/n_tty.c:826 [inline] __receive_buf drivers/tty/n_tty.c:1579 [inline] n_tty_receive_buf_common+0x1699/0x4780 drivers/tty/n_tty.c:1674 tty_ldisc_receive_buf+0xa3/0x190 drivers/tty/tty_buffer.c:471 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:39 receive_buf drivers/tty/tty_buffer.c:491 [inline] flush_to_ldisc+0x20d/0x380 drivers/tty/tty_buffer.c:543 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 NMI backtrace for cpu 0 CPU: 0 PID: 14770 Comm: systemd-cgroups Not tainted 5.15.0-rc6-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_dump_cpu_stacks+0x25e/0x3f0 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.cold+0x9d/0x746 kernel/rcu/tree.c:2599 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:1421 __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+0x40/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:194 Code: 74 24 10 e8 6a 16 22 f8 48 89 ef e8 b2 8c 22 f8 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 63 78 15 f8 65 8b 05 ec aa c8 76 85 c0 74 0a 5b 5d c3 e8 80 f3 RSP: 0018:ffffc90000007b08 EFLAGS: 00000206 RAX: 0000000000000012 RBX: 0000000000000200 RCX: 1ffffffff1fad512 RDX: 0000000000000000 RSI: 0000000000000101 RDI: 0000000000000001 RBP: ffff88801eb8c000 R08: 0000000000000001 R09: ffffffff8fd05aef R10: 0000000000000001 R11: 0000000000000000 R12: ffff88801fd3c440 R13: ffff8880200f4300 R14: dffffc0000000000 R15: ffff88801fd3c438 spin_unlock_irqrestore include/linux/spinlock.h:418 [inline] dummy_timer+0x12f6/0x32b0 drivers/usb/gadget/udc/dummy_hcd.c:2001 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:down_read+0x95/0x440 kernel/locking/rwsem.c:1464 Code: 60 31 c0 e8 7d 1a 16 f8 66 66 48 31 c0 48 8d 7b 70 45 31 c9 31 d2 41 b8 01 00 00 00 b9 01 00 00 00 31 f6 ff b4 24 98 00 00 00 96 b1 22 f8 be 08 00 00 00 48 89 df e8 c9 2e 84 f8 b8 00 01 00 RSP: 0018:ffffc900069b7a58 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff88806e09d208 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88806e09d278 RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000 R10: ffffed100e9be881 R11: 0000000000000000 R12: 1ffff92000d36f4d R13: dffffc0000000000 R14: ffff88806e09d200 R15: ffff888084cf17a0 anon_vma_lock_read include/linux/rmap.h:126 [inline] validate_mm+0xd3/0x800 mm/mmap.c:404 __vma_adjust+0x1097/0x2530 mm/mmap.c:1021 vma_adjust include/linux/mm.h:2546 [inline] __split_vma+0x467/0x550 mm/mmap.c:2740 split_vma+0x95/0xd0 mm/mmap.c:2772 mprotect_fixup+0x678/0x940 mm/mprotect.c:477 do_mprotect_pkey+0x558/0x9a0 mm/mprotect.c:636 __do_sys_mprotect mm/mprotect.c:662 [inline] __se_sys_mprotect mm/mprotect.c:659 [inline] __x64_sys_mprotect+0x74/0xb0 mm/mprotect.c:659 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: 0033:0x7f7a4a4623a7 Code: ff 66 90 b8 0b 00 00 00 0f 05 48 3d 01 f0 ff ff 73 01 c3 48 8d 0d 89 bd 20 00 f7 d8 89 01 48 83 c8 ff c3 b8 0a 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8d 0d 69 bd 20 00 f7 d8 89 01 48 83 RSP: 002b:00007ffd3cdd9ae8 EFLAGS: 00000206 ORIG_RAX: 000000000000000a RAX: ffffffffffffffda RBX: 00007f7a4a6659e0 RCX: 00007f7a4a4623a7 RDX: 0000000000000000 RSI: 0000000000200000 RDI: 00007f7a48ff7000 RBP: 00007ffd3cdd9d90 R08: 0000000000000000 R09: 0000000000000000 R10: 00007ffd3cdd9af0 R11: 0000000000000206 R12: 00007ffd3cdd9e78 R13: 0000000000000002 R14: 0000000000000801 R15: 00007ffd3cdd9e30 usb 4-1: input irq status -75 received ---------------- Code disassembly (best guess): 0: 48 89 74 38 e8 mov %rsi,-0x18(%rax,%rdi,1) 5: 4e 89 54 c8 20 mov %r10,0x20(%rax,%r9,8) a: 48 89 10 mov %rdx,(%rax) d: c3 retq e: 0f 1f 40 00 nopl 0x0(%rax) 12: 49 89 f8 mov %rdi,%r8 15: bf 03 00 00 00 mov $0x3,%edi 1a: 4c 8b 14 24 mov (%rsp),%r10 1e: 48 89 f1 mov %rsi,%rcx 21: 65 48 8b 34 25 40 f0 mov %gs:0x1f040,%rsi 28: 01 00 * 2a: e8 53 f0 ff ff callq 0xfffff082 <-- trapping instruction 2f: 84 c0 test %al,%al 31: 74 48 je 0x7b 33: 48 8b 86 48 15 00 00 mov 0x1548(%rsi),%rax 3a: 8b b6 44 15 00 00 mov 0x1544(%rsi),%esi