rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10040 ticks this GP) idle=5c7/1/0x4000000000000000 softirq=35309/35309 fqs=0 (t=10500 jiffies g=61973 q=35) rcu: rcu_preempt kthread starved for 10040 jiffies! g61973 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:28208 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6459 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x57/0x70 kernel/locking/spinlock.c:194 __mod_timer+0x837/0xe30 kernel/time/timer.c:1065 schedule_timeout+0x145/0x2a0 kernel/time/timer.c:1880 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: NMI backtrace for cpu 0 CPU: 0 PID: 17007 Comm: syz-executor.2 Not tainted 5.15.0-rc5-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_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:481 print_cpu_stall kernel/rcu/tree_stall.h:625 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq.cold+0x98/0x746 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+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:kfree+0x137/0x2c0 mm/slab.c:3805 Code: 0e 4c 89 ea 48 89 ee 4c 89 e7 e8 d4 f8 ff ff 48 85 db 0f 85 a6 00 00 00 9c 58 f6 c4 02 0f 85 74 01 00 00 48 85 db 74 01 fb 5b <5d> 41 5c 41 5d c3 65 8b 05 94 2b 45 7e 83 f8 07 0f 87 61 01 00 00 RSP: 0018:ffffc9000509f8a0 EFLAGS: 00000206 RAX: 0000000000000002 RBX: fffffffffffffff5 RCX: 1ffffffff1adc361 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88806b598380 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817c38d8 R11: 0000000000086089 R12: ffff888010c40100 R13: ffffffff842f58a0 R14: dffffc0000000000 R15: ffff88801e6dca80 tty_free_file drivers/tty/tty_io.c:220 [inline] tty_open+0x7e0/0x1000 drivers/tty/tty_io.c:2149 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: 0033:0x7f85b7751a39 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:00007f85b4cc7188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f85b7854f60 RCX: 00007f85b7751a39 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f85b77abc5f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff9c17559f R14: 00007f85b4cc7300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 17007 Comm: syz-executor.2 Not tainted 5.15.0-rc5-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+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:kfree+0x137/0x2c0 mm/slab.c:3805 Code: 0e 4c 89 ea 48 89 ee 4c 89 e7 e8 d4 f8 ff ff 48 85 db 0f 85 a6 00 00 00 9c 58 f6 c4 02 0f 85 74 01 00 00 48 85 db 74 01 fb 5b <5d> 41 5c 41 5d c3 65 8b 05 94 2b 45 7e 83 f8 07 0f 87 61 01 00 00 RSP: 0018:ffffc9000509f8a0 EFLAGS: 00000206 RAX: 0000000000000002 RBX: fffffffffffffff5 RCX: 1ffffffff1adc361 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88806b598380 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817c38d8 R11: 0000000000086089 R12: ffff888010c40100 R13: ffffffff842f58a0 R14: dffffc0000000000 R15: ffff88801e6dca80 tty_free_file drivers/tty/tty_io.c:220 [inline] tty_open+0x7e0/0x1000 drivers/tty/tty_io.c:2149 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: 0033:0x7f85b7751a39 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:00007f85b4cc7188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f85b7854f60 RCX: 00007f85b7751a39 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f85b77abc5f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff9c17559f R14: 00007f85b4cc7300 R15: 0000000000022000 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 17006 Comm: syz-executor.0 Not tainted 5.15.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rdtsc_ordered arch/x86/include/asm/msr.h:234 [inline] RIP: 0010:read_tsc+0x3/0x10 arch/x86/kernel/tsc.c:1095 Code: cc cc cc cc cc cc cc 8b 05 8e 90 43 0c c3 66 0f 1f 84 00 00 00 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 0f 01 f9 <66> 90 48 c1 e2 20 48 09 d0 c3 0f 1f 00 48 c7 c0 10 1b 6e 8d 48 ba RSP: 0000:ffffc90000fd8be8 EFLAGS: 00000046 RAX: 00000000f840cb20 RBX: 00000000000179b0 RCX: 0000000000000001 RDX: 00000000000000fb RSI: ffffffff81665004 RDI: ffffffff8b7a3240 RBP: 00000000000179b0 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff81664ffa R11: 0000000000000000 R12: ffffffff8b7a3240 R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b9d22440 FS: 00007fab39c6a700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2df27000 CR3: 000000007d52e000 CR4: 00000000003526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tk_clock_read kernel/time/timekeeping.c:193 [inline] timekeeping_get_delta kernel/time/timekeeping.c:253 [inline] timekeeping_get_ns kernel/time/timekeeping.c:386 [inline] ktime_get+0x1e4/0x470 kernel/time/timekeeping.c:829 hrtimer_forward_now include/linux/hrtimer.h:506 [inline] perf_swevent_hrtimer+0x246/0x3f0 kernel/events/core.c:10572 __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+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:kfree+0x137/0x2c0 mm/slab.c:3805 Code: 0e 4c 89 ea 48 89 ee 4c 89 e7 e8 d4 f8 ff ff 48 85 db 0f 85 a6 00 00 00 9c 58 f6 c4 02 0f 85 74 01 00 00 48 85 db 74 01 fb 5b <5d> 41 5c 41 5d c3 65 8b 05 94 2b 45 7e 83 f8 07 0f 87 61 01 00 00 RSP: 0000:ffffc9000476f8a0 EFLAGS: 00000206 RAX: 0000000000000006 RBX: fffffffffffffff5 RCX: 1ffffffff1adc361 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88806d083400 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817c38d8 R11: 0000000000086089 R12: ffff888010c40100 R13: ffffffff842f58a0 R14: dffffc0000000000 R15: ffff88801ed9a040 tty_free_file drivers/tty/tty_io.c:220 [inline] tty_open+0x7e0/0x1000 drivers/tty/tty_io.c:2149 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: 0033:0x7fab3c6f4a39 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:00007fab39c6a188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fab3c7f7f60 RCX: 00007fab3c6f4a39 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007fab3c74ec5f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff7e5da3af R14: 00007fab39c6a300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 4c 89 ea mov %r13,%rdx 3: 48 89 ee mov %rbp,%rsi 6: 4c 89 e7 mov %r12,%rdi 9: e8 d4 f8 ff ff callq 0xfffff8e2 e: 48 85 db test %rbx,%rbx 11: 0f 85 a6 00 00 00 jne 0xbd 17: 9c pushfq 18: 58 pop %rax 19: f6 c4 02 test $0x2,%ah 1c: 0f 85 74 01 00 00 jne 0x196 22: 48 85 db test %rbx,%rbx 25: 74 01 je 0x28 27: fb sti 28: 5b pop %rbx * 29: 5d pop %rbp <-- trapping instruction 2a: 41 5c pop %r12 2c: 41 5d pop %r13 2e: c3 retq 2f: 65 8b 05 94 2b 45 7e mov %gs:0x7e452b94(%rip),%eax # 0x7e452bca 36: 83 f8 07 cmp $0x7,%eax 39: 0f 87 61 01 00 00 ja 0x1a0