INFO: rcu_preempt self-detected stall on CPU 0-...: (10499 ticks this GP) idle=4ee/140000000000001/0 softirq=15532/15532 fqs=2 (t=10500 jiffies g=3224 c=3223 q=132) rcu_preempt kthread starved for 10496 jiffies! g3224 c3223 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 rcu_preempt R running task 30008 8 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_timeout+0x4af/0xe90 kernel/time/timer.c:1747 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 NMI backtrace for cpu 0 CPU: 0 PID: 11541 Comm: syz-executor.4 Not tainted 4.14.275-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:158 [inline] rcu_dump_cpu_stacks+0x15f/0x19c kernel/rcu/tree.c:1396 print_cpu_stall kernel/rcu/tree.c:1542 [inline] check_cpu_stall kernel/rcu/tree.c:1610 [inline] __rcu_pending kernel/rcu/tree.c:3390 [inline] rcu_pending kernel/rcu/tree.c:3452 [inline] rcu_check_callbacks.cold+0x464/0xd8d kernel/rcu/tree.c:2792 update_process_times+0x29/0x60 kernel/time/timer.c:1591 tick_sched_handle+0x7d/0x150 kernel/time/tick-sched.c:165 tick_sched_timer+0x92/0x200 kernel/time/tick-sched.c:1223 __run_hrtimer kernel/time/hrtimer.c:1223 [inline] __hrtimer_run_queues+0x30b/0xc80 kernel/time/hrtimer.c:1287 hrtimer_interrupt+0x1e6/0x5e0 kernel/time/hrtimer.c:1321 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1079 [inline] smp_apic_timer_interrupt+0x117/0x5e0 arch/x86/kernel/apic/apic.c:1104 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793 RIP: 0010:preempt_count_add+0x64/0x170 kernel/sched/core.c:3110 RSP: 0018:ffff88805b06f5d0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10 RAX: dffffc0000000000 RBX: 0000000000000003 RCX: 0000000000000000 RDX: 1ffffffff17da1a8 RSI: ffff88805b06f598 RDI: 0000000000000001 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001 R10: ffff88805b06fbb0 R11: 0000000000000001 R12: ffff88805b06f730 R13: ffff88805b06f6e0 R14: ffff88813fe741c0 R15: ffff88805b06f6a8 unwind_next_frame+0xc2/0x17d0 arch/x86/kernel/unwind_orc.c:333 __save_stack_trace+0x90/0x160 arch/x86/kernel/stacktrace.c:44 save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] tty_alloc_file drivers/tty/tty_io.c:186 [inline] tty_open+0x11a/0x8b0 drivers/tty/tty_io.c:2015 chrdev_open+0x23c/0x6d0 fs/char_dev.c:423 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x628/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f313e9c2049 RSP: 002b:00007f313d337168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f313ead4f60 RCX: 00007f313e9c2049 RDX: 0000000000000000 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 00007f313ea1c08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcfd1220ef R14: 00007f313d337300 R15: 0000000000022000 INFO: rcu_sched detected stalls on CPUs/tasks: 0-...: (1 GPs behind) idle=4ee/140000000000001/0 softirq=15531/15532 fqs=1 (detected by 1, t=10566 jiffies, g=1561, c=1560, q=1) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 11541 Comm: syz-executor.4 Not tainted 4.14.275-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880958aa040 task.stack: ffff88805b068000 RIP: 0010:bytes_is_nonzero mm/kasan/kasan.c:167 [inline] RIP: 0010:memory_is_nonzero mm/kasan/kasan.c:184 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/kasan.c:210 [inline] RIP: 0010:memory_is_poisoned mm/kasan/kasan.c:241 [inline] RIP: 0010:check_memory_region_inline mm/kasan/kasan.c:257 [inline] RIP: 0010:check_memory_region+0xcb/0x170 mm/kasan/kasan.c:267 RSP: 0018:ffff88805b06f5c0 EFLAGS: 00000246 RAX: ffffed100b60dedb RBX: ffffed100b60dee0 RCX: ffffffff812387b6 RDX: ffffed100b60dee0 RSI: 0000000000000058 RDI: ffff88805b06f6a8 RBP: ffffed100b60ded5 R08: 0000000000000001 R09: ffffed100b60dedf R10: ffff88805b06f6ff R11: ffff8880958aa040 R12: 0000000000000058 R13: 0000000000000000 R14: dffffc0000000000 R15: ffff88805b06f6a8 FS: 00007f313d337700(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe0c7c1c10 CR3: 0000000099331000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: memset+0x20/0x40 mm/kasan/kasan.c:285 memset include/linux/string.h:361 [inline] __unwind_start+0x66/0x930 arch/x86/kernel/unwind_orc.c:511 unwind_start arch/x86/include/asm/unwind.h:60 [inline] __save_stack_trace+0x63/0x160 arch/x86/kernel/stacktrace.c:43 save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] tty_alloc_file drivers/tty/tty_io.c:186 [inline] tty_open+0x11a/0x8b0 drivers/tty/tty_io.c:2015 chrdev_open+0x23c/0x6d0 fs/char_dev.c:423 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x628/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f313e9c2049 RSP: 002b:00007f313d337168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f313ead4f60 RCX: 00007f313e9c2049 RDX: 0000000000000000 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 00007f313ea1c08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcfd1220ef R14: 00007f313d337300 R15: 0000000000022000 Code: 74 0e 80 38 00 74 f2 48 85 c0 0f 85 9c 00 00 00 5b 5d 41 5c c3 48 85 d2 74 f6 48 01 ea eb 09 48 83 c0 01 48 39 d0 74 e8 80 38 00 <74> f2 eb d8 41 bc 08 00 00 00 48 89 ea 45 29 dc 4e 8d 5c 25 00 rcu_sched kthread starved for 10564 jiffies! g1561 c1560 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 rcu_sched R running task 30008 9 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_timeout+0x4af/0xe90 kernel/time/timer.c:1747 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 ---------------- Code disassembly (best guess): 0: 74 0e je 0x10 2: 80 38 00 cmpb $0x0,(%rax) 5: 74 f2 je 0xfffffff9 7: 48 85 c0 test %rax,%rax a: 0f 85 9c 00 00 00 jne 0xac 10: 5b pop %rbx 11: 5d pop %rbp 12: 41 5c pop %r12 14: c3 retq 15: 48 85 d2 test %rdx,%rdx 18: 74 f6 je 0x10 1a: 48 01 ea add %rbp,%rdx 1d: eb 09 jmp 0x28 1f: 48 83 c0 01 add $0x1,%rax 23: 48 39 d0 cmp %rdx,%rax 26: 74 e8 je 0x10 28: 80 38 00 cmpb $0x0,(%rax) * 2b: 74 f2 je 0x1f <-- trapping instruction 2d: eb d8 jmp 0x7 2f: 41 bc 08 00 00 00 mov $0x8,%r12d 35: 48 89 ea mov %rbp,%rdx 38: 45 29 dc sub %r11d,%r12d 3b: 4e 8d 5c 25 00 lea 0x0(%rbp,%r12,1),%r11