rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=7a14/1/0x4000000000000000 softirq=50610/50610 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13075/1:b..l rcu: (detected by 0, t=10502 jiffies, g=71881, q=97 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 14685 Comm: syz-executor.0 Not tainted 6.4.0-next-20230630-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 RIP: 0010:__lock_acquire+0x904/0x5e20 kernel/locking/lockdep.c:5114 Code: 89 ee 4c 89 e7 e8 cc d8 ff ff 85 c0 0f 84 8c 05 00 00 ba 08 00 00 00 48 89 ee 4c 89 e7 e8 b4 d8 ff ff 85 c0 0f 84 74 05 00 00 <48> c7 c2 c0 65 15 92 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f RSP: 0018:ffffc900001e0b20 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 1ffff9200003c196 RCX: 1ffffffff230d3a0 RDX: ffffffff91869ca0 RSI: 0000000000000008 RDI: ffffffff91869d00 RBP: ffff888044a02888 R08: 0000000000000000 R09: fffffbfff230cfd0 R10: 0000000000000001 R11: 0000000000000001 R12: ffff888044a01dc0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000555555ab1400(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efdfbfa8000 CR3: 000000002b1f5000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5726 rcu_lock_acquire include/linux/rcupdate.h:302 [inline] rcu_read_lock include/linux/rcupdate.h:748 [inline] advance_sched+0x6e4/0xd20 net/sched/sch_taprio.c:996 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x604/0xc00 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x320/0x7b0 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1098 [inline] __sysvec_apic_timer_interrupt+0x14a/0x430 arch/x86/kernel/apic/apic.c:1115 sysvec_apic_timer_interrupt+0x92/0xc0 arch/x86/kernel/apic/apic.c:1109 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:91 [inline] RIP: 0010:syscall_enter_from_user_mode+0x30/0x80 kernel/entry/common.c:112 Code: 49 89 f4 55 48 89 fd 53 48 8b 7c 24 18 e8 58 fa ff ff 66 90 66 90 e8 2f c9 6a f7 e8 9a c7 6a f7 fb 65 48 8b 04 25 c0 b9 03 00 <48> 8b 70 08 40 f6 c6 3f 75 38 5b 4c 89 e0 5d 41 5c c3 e8 19 12 00 RSP: 0018:ffffc90005487f20 EFLAGS: 00000206 RAX: ffff888044a01dc0 RBX: 0000000000000000 RCX: 1ffffffff1d547a9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90005487f58 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff8eaa6ed7 R11: 0000000000000000 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 do_syscall_64+0x1a/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7efdfbe3e12b Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44 RSP: 002b:00007ffcdb241740 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000010 RCX: 00007efdfbe3e12b RDX: ffffffffffffffb8 RSI: ffffffffffffffff RDI: 000000000000000f RBP: 00007efdfbfad980 R08: 0000000000000000 R09: 00007efdfba00000 R10: 00007efdfba00d10 R11: 0000000000000293 R12: 00000000001028e8 R13: 00007ffcdb241840 R14: 00007efdfbfabf80 R15: 0000000000000032 task:udevd state:R running task stack:24680 pid:13075 ppid:4480 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0xc9a/0x5880 kernel/sched/core.c:6709 preempt_schedule_common+0x45/0xb0 kernel/sched/core.c:6878 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x5b/0x70 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:405 [inline] __wake_up_common_lock+0xe2/0x140 kernel/sched/wait.c:140 sock_def_readable+0x158/0x760 net/core/sock.c:3311 unix_dgram_sendmsg+0xf69/0x1b70 net/unix/af_unix.c:2084 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg+0xde/0x190 net/socket.c:748 sock_write_iter+0x29b/0x3d0 net/socket.c:1129 call_write_iter include/linux/fs.h:1871 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x981/0xda0 fs/read_write.c:584 ksys_write+0x1e3/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f7885516bf2 RSP: 002b:00007ffd00aa1d28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7885516bf2 RDX: 0000000000000000 RSI: 00007ffd00aa1d7f RDI: 000000000000000a RBP: 00007ffd00aa1d7f R08: 0000000000000001 R09: 0000000000000000 R10: 000000000000010f R11: 0000000000000246 R12: 000000000000000a R13: 00007f7885991ae0 R14: 0000000000000000 R15: 000055c6387a0910 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g71881 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=59862 rcu: rcu_preempt kthread starved for 10502 jiffies! g71881 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:28704 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0xc9a/0x5880 kernel/sched/core.c:6709 schedule+0xde/0x1a0 kernel/sched/core.c:6785 schedule_timeout+0x14e/0x2b0 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x190/0x910 kernel/rcu/tree.c:1609 rcu_gp_kthread+0x23a/0x360 kernel/rcu/tree.c:1808 kthread+0x344/0x440 kernel/kthread.c:389 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 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: 14685 Comm: syz-executor.0 Not tainted 6.4.0-next-20230630-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:228 [inline] RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:240 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:504 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1082 [inline] RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0xc1/0x520 kernel/locking/lockdep.c:5732 Code: 87 e3 03 00 00 89 d2 be 08 00 00 00 48 89 d0 48 89 54 24 08 48 c1 e8 06 48 8d 3c c5 d0 6e aa 8e e8 24 ce 71 00 48 8b 54 24 08 <48> 0f a3 15 37 f1 43 0d 0f 82 9c 03 00 00 48 c7 c0 f0 a3 aa 8e 48 RSP: 0018:ffffc900001e0c28 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 1ffff9200003c187 RCX: ffffffff81667d8c RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8eaa6ed0 RBP: 0000000000000001 R08: 0000000000000000 R09: fffffbfff1d54dda R10: ffffffff8eaa6ed7 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000001 R14: ffffffff8d358a80 R15: 0000000000000000 FS: 0000555555ab1400(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efdfbfa8000 CR3: 000000002b1f5000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_objects_fill_pool lib/debugobjects.c:614 [inline] debug_object_activate+0x128/0x4f0 lib/debugobjects.c:713 debug_hrtimer_activate kernel/time/hrtimer.c:422 [inline] debug_activate kernel/time/hrtimer.c:477 [inline] enqueue_hrtimer+0x27/0x320 kernel/time/hrtimer.c:1087 __run_hrtimer kernel/time/hrtimer.c:1705 [inline] __hrtimer_run_queues+0xa65/0xc00 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x320/0x7b0 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1098 [inline] __sysvec_apic_timer_interrupt+0x14a/0x430 arch/x86/kernel/apic/apic.c:1115 sysvec_apic_timer_interrupt+0x92/0xc0 arch/x86/kernel/apic/apic.c:1109 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:91 [inline] RIP: 0010:syscall_enter_from_user_mode+0x30/0x80 kernel/entry/common.c:112 Code: 49 89 f4 55 48 89 fd 53 48 8b 7c 24 18 e8 58 fa ff ff 66 90 66 90 e8 2f c9 6a f7 e8 9a c7 6a f7 fb 65 48 8b 04 25 c0 b9 03 00 <48> 8b 70 08 40 f6 c6 3f 75 38 5b 4c 89 e0 5d 41 5c c3 e8 19 12 00 RSP: 0018:ffffc90005487f20 EFLAGS: 00000206 RAX: ffff888044a01dc0 RBX: 0000000000000000 RCX: 1ffffffff1d547a9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90005487f58 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff8eaa6ed7 R11: 0000000000000000 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 do_syscall_64+0x1a/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7efdfbe3e12b Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44 RSP: 002b:00007ffcdb241740 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000010 RCX: 00007efdfbe3e12b RDX: ffffffffffffffb8 RSI: ffffffffffffffff RDI: 000000000000000f RBP: 00007efdfbfad980 R08: 0000000000000000 R09: 00007efdfba00000 R10: 00007efdfba00d10 R11: 0000000000000293 R12: 00000000001028e8 R13: 00007ffcdb241840 R14: 00007efdfbfabf80 R15: 0000000000000032