rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=afa/1/0x4000000000000004 softirq=224877/224877 fqs=0 (t=10501 jiffies g=274737 q=329) rcu: rcu_preempt kthread starved for 10502 jiffies! g274737 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29264 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3386 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4082 schedule+0xdc/0x2b0 kernel/sched/core.c:4156 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1658 [inline] rcu_gp_kthread+0xa10/0x1940 kernel/rcu/tree.c:1818 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 0 CPU: 0 PID: 12882 Comm: syz-executor.5 Not tainted 5.5.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:475 [inline] check_cpu_stall kernel/rcu/tree_stall.h:549 [inline] rcu_pending kernel/rcu/tree.c:3030 [inline] rcu_sched_clock_irq.cold+0x51a/0xc37 kernel/rcu/tree.c:2276 update_process_times+0x2d/0x70 kernel/time/timer.c:1726 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:171 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1314 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:debug_lockdep_rcu_enabled.part.0+0xf/0x60 kernel/rcu/update.c:252 Code: 4c 89 ff e8 73 8c 52 00 e9 3d fe ff ff 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 53 <65> 48 8b 1c 25 c0 1e 02 00 48 8d bb 94 08 00 00 48 89 fa 48 c1 ea RSP: 0018:ffffc90000007c68 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffffc90000007cb8 RCX: 1ffffffff1549d76 RDX: 0000000000000000 RSI: ffffffff8164bb09 RDI: ffffc90000007cb8 RBP: ffffc90000007c70 R08: ffff888056a2e080 R09: fffffbfff1549739 R10: fffffbfff1549738 R11: ffffffff8aa4b9c7 R12: 0000000000000100 R13: ffffc90000007db0 R14: 0000000000000000 R15: dffffc0000000000 debug_lockdep_rcu_enabled kernel/rcu/update.c:251 [inline] rcu_read_lock_held_common+0x7d/0x130 kernel/rcu/update.c:100 rcu_read_lock_sched_held+0x5b/0xd0 kernel/rcu/update.c:119 trace_timer_expire_entry include/trace/events/timer.h:90 [inline] call_timer_fn+0x6de/0x780 kernel/time/timer.c:1403 expire_timers kernel/time/timer.c:1449 [inline] __run_timers kernel/time/timer.c:1773 [inline] __run_timers kernel/time/timer.c:1740 [inline] run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:_snd_pcm_hw_param_min+0x0/0x560 sound/core/oss/pcm_oss.c:200 Code: e9 90 c3 ff ff e8 b0 17 66 fb 44 89 fe 48 c7 c7 00 00 f0 88 e8 05 29 4f fb e9 77 c3 ff ff cc cc cc cc cc cc cc cc cc cc cc cc <55> 48 89 e5 41 57 41 89 d7 41 56 41 55 41 89 cd 41 54 49 89 fc 53 RSP: 0018:ffffc9000eb97408 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: ffffffff897c0d10 RCX: 0000000000000000 RDX: 0000000000000002 RSI: 000000000000000f RDI: ffff88801db49000 RBP: ffffc9000eb975b8 R08: ffff888056a2e080 R09: ffff88801db49044 R10: ffffed1003b69209 R11: ffff88801db4904b R12: 0000000000000000 R13: 0000000000000000 R14: ffff88801db49000 R15: ffff88809b025000 snd_pcm_oss_change_params+0x7b/0xd0 sound/core/oss/pcm_oss.c:1087 snd_pcm_oss_make_ready+0xbe/0x170 sound/core/oss/pcm_oss.c:1146 snd_pcm_oss_set_trigger.isra.0+0x365/0x790 sound/core/oss/pcm_oss.c:2046 snd_pcm_oss_poll+0x5c0/0xa60 sound/core/oss/pcm_oss.c:2830 vfs_poll include/linux/poll.h:90 [inline] do_select+0x922/0x16f0 fs/select.c:534 core_sys_select+0x444/0x9e0 fs/select.c:677 do_pselect.constprop.0+0x199/0x1e0 fs/select.c:759 __do_sys_pselect6 fs/select.c:784 [inline] __se_sys_pselect6 fs/select.c:769 [inline] __x64_sys_pselect6+0x1fc/0x2e0 fs/select.c:769 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b399 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fadb7e00c78 EFLAGS: 00000246 ORIG_RAX: 000000000000010e RAX: ffffffffffffffda RBX: 00007fadb7e016d4 RCX: 000000000045b399 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000040 RBP: 000000000075bf20 R08: 00000000200001c0 R09: 0000000000000000 R10: 0000000020000140 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000854 R14: 00000000004c9ca7 R15: 000000000075bf2c Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 534 Comm: kworker/u4:6 Not tainted 5.5.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:csd_lock_wait kernel/smp.c:109 [inline] RIP: 0010:smp_call_function_single+0x188/0x480 kernel/smp.c:311 Code: 00 e8 cc 22 0b 00 48 8b 4c 24 08 48 8b 54 24 10 48 8d 74 24 40 8b 7c 24 1c e8 c4 f9 ff ff 41 89 c5 eb 07 e8 aa 22 0b 00 f3 90 <44> 8b 64 24 58 31 ff 41 83 e4 01 44 89 e6 e8 15 24 0b 00 45 85 e4 RSP: 0018:ffffc90002c66cc0 EFLAGS: 00000293 RAX: ffff8880a7dfa480 RBX: 1ffff9200058cd9c RCX: ffffffff816a12ab RDX: 0000000000000000 RSI: ffffffff816a1296 RDI: 0000000000000005 RBP: ffffc90002c66d88 R08: ffff8880a7dfa480 R09: ffffed1015d07099 R10: ffffed1015d07098 R11: ffff8880ae8384c7 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd94c5b7db8 CR3: 00000000a00ba000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: smp_call_function_many_cond+0x1af/0x9b0 kernel/smp.c:439 on_each_cpu_cond_mask+0x5a/0x2b0 kernel/smp.c:694 native_flush_tlb_others+0x21a/0x4e0 arch/x86/mm/tlb.c:710 flush_tlb_others arch/x86/include/asm/paravirt.h:68 [inline] flush_tlb_mm_range+0x299/0x4e0 arch/x86/mm/tlb.c:798 flush_tlb_page arch/x86/include/asm/tlbflush.h:585 [inline] ptep_clear_flush+0x141/0x170 mm/pgtable-generic.c:97 page_mkclean_one+0x3c9/0x740 mm/rmap.c:937 rmap_walk_file+0x585/0xcf0 mm/rmap.c:1920 rmap_walk+0x130/0x1c0 mm/rmap.c:1938 page_mkclean+0x269/0x340 mm/rmap.c:1005 clear_page_dirty_for_io+0x35f/0xde0 mm/page-writeback.c:2690 mpage_submit_page+0x8d/0x2e0 fs/ext4/inode.c:2054 mpage_process_page_bufs+0x666/0x780 fs/ext4/inode.c:2188 mpage_prepare_extent_to_map+0xa05/0xf90 fs/ext4/inode.c:2597 ext4_writepages+0x954/0x3080 fs/ext4/inode.c:2725 do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344 __writeback_single_inode+0x136/0x1400 fs/fs-writeback.c:1452 writeback_sb_inodes+0x596/0xf20 fs/fs-writeback.c:1716 __writeback_inodes_wb+0xc3/0x260 fs/fs-writeback.c:1785 wb_writeback+0x910/0xd90 fs/fs-writeback.c:1894 wb_check_old_data_flush fs/fs-writeback.c:1996 [inline] wb_do_writeback fs/fs-writeback.c:2049 [inline] wb_workfn+0xbc1/0x1280 fs/fs-writeback.c:2078 process_one_work+0xa05/0x17a0 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 0.000 msecs