rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=11469, q=53) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295004315-4294993812), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10504 jiffies! g11469 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:28568 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: 6614 Comm: syz-executor000 Not tainted 5.15.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:debug_object_deactivate+0x2/0x300 lib/debugobjects.c:724 Code: ff ff 48 89 cf 48 89 54 24 18 48 89 4c 24 10 e8 b4 75 de fd 48 8b 54 24 18 48 8b 4c 24 10 e9 e2 f4 ff ff 0f 1f 44 00 00 41 57 <41> 56 41 55 41 54 49 bc 00 00 00 00 00 fc ff df 55 53 48 81 ec b0 RSP: 0018:ffffc90000fd8e30 EFLAGS: 00000046 RAX: 0000000080010001 RBX: ffff888073ea6ed8 RCX: 0000000000000000 RDX: ffff88802772a200 RSI: ffffffff898ddd80 RDI: ffff888073ea6ed8 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff8165bd95 R11: 0000000000000000 R12: 0000009c6c0edc8a R13: ffff8880b9d22440 R14: ffff8880b9d223c0 R15: ffff8880b9d223c0 FS: 00007f81244a0700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000280 CR3: 0000000077e35000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline] debug_deactivate kernel/time/hrtimer.c:481 [inline] __run_hrtimer kernel/time/hrtimer.c:1653 [inline] __hrtimer_run_queues+0x3f8/0xe50 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:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline] RIP: 0010:lock_is_held_type+0x51/0x140 kernel/locking/lockdep.c:5664 Code: cb 76 85 c0 0f 85 c8 00 00 00 65 4c 8b 24 25 40 f0 01 00 41 8b 94 24 1c 0a 00 00 85 d2 0f 85 af 00 00 00 48 89 fd 41 89 f6 9c <8f> 04 24 fa 48 c7 c7 60 e9 8b 89 31 db e8 2d 0e 00 00 41 8b 84 24 RSP: 0018:ffffc90002ee76f0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8b97efe0 RBP: ffffffff8b97efe0 R08: ffffffff842f564e R09: ffff8880b9d32a8b R10: ffffffff842f5271 R11: 0000000000086089 R12: ffff88802772a200 R13: 00000000ffffffff R14: 00000000ffffffff R15: ffff88801f08c7c0 lock_is_held include/linux/lockdep.h:283 [inline] ___might_sleep+0x3a/0x2c0 kernel/sched/core.c:9504 __mutex_lock_common kernel/locking/mutex.c:573 [inline] __mutex_lock+0xa1/0x12f0 kernel/locking/mutex.c:729 tty_open_by_driver drivers/tty/tty_io.c:2062 [inline] tty_open+0x55e/0x1000 drivers/tty/tty_io.c:2146 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: 0033:0x7f81244eeaf9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f81244a0318 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f81245763e8 RCX: 00007f81244eeaf9 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f81245763e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 7974742f7665642f R13: 00007ffcdc3371ff R14: 00007f81244a0400 R15: 0000000000022000 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.871 msecs ---------------- Code disassembly (best guess), 1 bytes skipped: 0: ff 48 89 decl -0x77(%rax) 3: cf iret 4: 48 89 54 24 18 mov %rdx,0x18(%rsp) 9: 48 89 4c 24 10 mov %rcx,0x10(%rsp) e: e8 b4 75 de fd callq 0xfdde75c7 13: 48 8b 54 24 18 mov 0x18(%rsp),%rdx 18: 48 8b 4c 24 10 mov 0x10(%rsp),%rcx 1d: e9 e2 f4 ff ff jmpq 0xfffff504 22: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 27: 41 57 push %r15 * 29: 41 56 push %r14 <-- trapping instruction 2b: 41 55 push %r13 2d: 41 54 push %r12 2f: 49 bc 00 00 00 00 00 movabs $0xdffffc0000000000,%r12 36: fc ff df 39: 55 push %rbp 3a: 53 push %rbx 3b: 48 rex.W 3c: 81 .byte 0x81 3d: ec in (%dx),%al 3e: b0 .byte 0xb0