rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10498 ticks this GP) idle=b66/1/0x4000000000000000 softirq=111874/111874 fqs=5078 (t=10500 jiffies g=214941 q=961) NMI backtrace for cpu 0 CPU: 0 PID: 26378 Comm: syz-executor.4 Not tainted 5.9.0-rc6-next-20200922-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+0x198/0x1fb lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:165 [inline] rcu_dump_cpu_stacks+0x1e3/0x21e kernel/rcu/tree_stall.h:324 print_cpu_stall kernel/rcu/tree_stall.h:557 [inline] check_cpu_stall kernel/rcu/tree_stall.h:631 [inline] rcu_pending kernel/rcu/tree.c:3704 [inline] rcu_sched_clock_irq.cold+0x4db/0xdcf kernel/rcu/tree.c:2575 update_process_times+0x25/0xa0 kernel/time/timer.c:1710 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x1ce/0xea0 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1097 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] sysvec_apic_timer_interrupt+0x4c/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:653 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x4d/0x90 kernel/locking/spinlock.c:191 Code: 48 c7 c0 a8 f1 3c 8a 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 3c 48 83 3d 62 83 fc 01 00 74 29 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 e4 b0 0f f9 65 8b 05 1d 90 c1 77 RSP: 0018:ffffc90000007c18 EFLAGS: 00000286 RAX: 1ffffffff1479e35 RBX: 0000000000000286 RCX: ffffffff815a9cb7 RDX: dffffc0000000000 RSI: 0000000000000102 RDI: 0000000000000286 RBP: ffff8880ae4255c0 R08: 0000000000000001 R09: ffffffff8d6caaaf R10: fffffbfff1ad9555 R11: 0000000000000000 R12: 00000001000206a1 R13: ffff8880ae4255c0 R14: 0000000000000000 R15: 00000000ffffffff __mod_timer+0x837/0xe30 kernel/time/timer.c:1066 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1768 __do_softirq+0x203/0xab6 kernel/softirq.c:298 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:786 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x235/0x280 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 RIP: 0010:unwind_next_frame+0xc18/0x1f90 arch/x86/kernel/unwind_orc.c:538 Code: 24 20 4c 89 4c 24 18 e8 a6 a0 82 00 4c 8b 44 24 20 4c 8b 4c 24 18 e9 70 f7 ff ff e8 b9 78 cc ff e9 ee f7 ff ff 48 8b 44 24 60 <4c> 89 e2 4c 89 ff 48 89 4c 24 30 4c 89 4c 24 28 4c 89 44 24 20 48 RSP: 0018:ffffc90007677298 EFLAGS: 00000246 RAX: ffffc90007677780 RBX: 1ffff92000ecee5b RCX: ffffffff8c29d553 RDX: ffffc90007677758 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffffffff8c29d54e R09: ffffffff8c29d552 R10: 0000000000078084 R11: 0000000000000001 R12: ffffc900076773b8 R13: ffffc900076773a5 R14: ffffc900076773c0 R15: ffffc90007677370 arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 kmem_cache_alloc_node_trace+0x19f/0x5b0 mm/slab.c:3592 __do_kmalloc_node mm/slab.c:3612 [inline] __kmalloc_node+0x38/0x60 mm/slab.c:3620 kmalloc_node include/linux/slab.h:577 [inline] __vmalloc_area_node+0x589/0x7a0 mm/vmalloc.c:2429 __vmalloc_node_range mm/vmalloc.c:2511 [inline] __vmalloc_node mm/vmalloc.c:2554 [inline] vzalloc+0x116/0x1a0 mm/vmalloc.c:2607 n_tty_open+0x16/0x170 drivers/tty/n_tty.c:1914 tty_ldisc_open+0x9b/0x110 drivers/tty/tty_ldisc.c:463 tty_ldisc_setup+0x43/0x100 drivers/tty/tty_ldisc.c:772 tty_init_dev.part.0+0x1f4/0x610 drivers/tty/tty_io.c:1366 tty_init_dev include/linux/err.h:36 [inline] tty_open_by_driver drivers/tty/tty_io.c:1983 [inline] tty_open+0xb2e/0xf60 drivers/tty/tty_io.c:2031 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4b9/0x11b0 fs/open.c:817 do_open fs/namei.c:3252 [inline] path_openat+0x1b9a/0x2730 fs/namei.c:3369 do_filp_open+0x17e/0x3c0 fs/namei.c:3396 do_sys_openat2+0x16d/0x420 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_openat fs/open.c:1200 [inline] __se_sys_openat fs/open.c:1195 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1195 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e179 Code: 3d b2 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 0b b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fef90bf3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000024000 RCX: 000000000045e179 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffeae799bef R14: 00007fef90bf49c0 R15: 000000000118cf4c