rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 1, t=10502 jiffies, g=84249, q=899)
rcu: All QSes seen, last rcu_preempt kthread activity 10442 (4295003459-4294993017), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10442 jiffies! g84249 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:28872 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4322 [inline]
 __schedule+0x911/0x21b0 kernel/sched/core.c:5073
 schedule+0xcf/0x270 kernel/sched/core.c:5152
 schedule_timeout+0x14a/0x250 kernel/time/timer.c:1892
 rcu_gp_fqs_loop kernel/rcu/tree.c:2005 [inline]
 rcu_gp_kthread+0xd07/0x2250 kernel/rcu/tree.c:2178
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 23859 Comm: syz-executor.3 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 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:164 [inline]
 rcu_check_gp_kthread_starvation+0x1c7/0x1e4 kernel/rcu/tree_stall.h:478
 print_other_cpu_stall kernel/rcu/tree_stall.h:582 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:706 [inline]
 rcu_pending kernel/rcu/tree.c:3830 [inline]
 rcu_sched_clock_irq.cold+0x9a3/0x11dd kernel/rcu/tree.c:2650
 update_process_times+0x16d/0x200 kernel/time/timer.c:1796
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226
 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1369
 __run_hrtimer kernel/time/hrtimer.c:1537 [inline]
 __hrtimer_run_queues+0x1c0/0xe40 kernel/time/hrtimer.c:1601
 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:199
Code: 0f 1f 44 00 00 55 48 8b 74 24 08 48 89 fd 48 83 c7 18 e8 1e 0c 54 f8 48 89 ef e8 46 c2 54 f8 e8 c1 4b 74 f8 fb bf 01 00 00 00 <e8> 46 90 48 f8 65 8b 05 ef 5a fc 76 85 c0 74 02 5d c3 e8 4b b0 fa
RSP: 0018:ffffc90000dc0e10 EFLAGS: 00000202
RAX: 0000000000ca14c4 RBX: ffffffff877aa990 RCX: 1ffffffff1b89d19
RDX: 0000000000000000 RSI: 0000000000000101 RDI: 0000000000000001
RBP: ffff8880b9d241c0 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8179e0b8 R11: 0000000000000000 R12: ffffc90000dc0ea8
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880b9d241c0
 expire_timers kernel/time/timer.c:1475 [inline]
 __run_timers.part.0+0x66c/0xa50 kernel/time/timer.c:1745
 __run_timers kernel/time/timer.c:1726 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1758
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu kernel/softirq.c:422 [inline]
 irq_exit_rcu+0x134/0x200 kernel/softirq.c:434
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:unwind_next_frame+0xed4/0x1ce0 arch/x86/kernel/unwind_orc.c:611
Code: c0 74 08 3c 03 0f 8e 90 0a 00 00 41 3b 2e 0f 84 b9 05 00 00 bf 01 00 00 00 e8 88 9c 1b 00 b8 01 00 00 00 65 8b 15 2c 67 cf 7e <85> d2 0f 85 aa f1 ff ff e8 86 bc cd ff e9 a0 f1 ff ff 4c 8b 7c 24
RSP: 0018:ffffc90003597388 EFLAGS: 00000297
RAX: 0000000000000001 RBX: 1ffff920006b2e79 RCX: 0000000000000000
RDX: 0000000080000000 RSI: ffffc90003597480 RDI: 0000000000000001
RBP: ffffc900035974b0 R08: ffffffff8e3c80e0 R09: 0000000000000001
R10: fffff520006b2ea1 R11: 0000000000084087 R12: ffffc90003590000
R13: ffffc900035974e5 R14: ffffc900035974b0 R15: ffffc900035974e4
 __unwind_start+0x51b/0x800 arch/x86/kernel/unwind_orc.c:699
 unwind_start arch/x86/include/asm/unwind.h:60 [inline]
 arch_stack_walk+0x5c/0xe0 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:427 [inline]
 ____kasan_kmalloc mm/kasan/common.c:506 [inline]
 ____kasan_kmalloc mm/kasan/common.c:465 [inline]
 __kasan_kmalloc+0x99/0xc0 mm/kasan/common.c:515
 kmalloc include/linux/slab.h:554 [inline]
 proc_self_get_link+0x187/0x1f0 fs/proc/self.c:22
 pick_link fs/namei.c:1738 [inline]
 step_into+0x1483/0x1c80 fs/namei.c:1799
 walk_component+0x171/0x6a0 fs/namei.c:1949
 link_path_walk.part.0+0x712/0xc90 fs/namei.c:2270
 link_path_walk fs/namei.c:2195 [inline]
 path_openat+0x25a/0x27e0 fs/namei.c:3496
 do_filp_open+0x190/0x3d0 fs/namei.c:3527
 do_sys_openat2+0x16d/0x420 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_openat fs/open.c:1219 [inline]
 __se_sys_openat fs/open.c:1214 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1214
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x419544
Code: 84 00 00 00 00 00 44 89 54 24 0c e8 96 f9 ff ff 44 8b 54 24 0c 44 89 e2 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 89 44 24 0c e8 c8 f9 ff ff 8b 44
RSP: 002b:00007fb12a3a70b0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000419544
RDX: 0000000000000000 RSI: 00000000004be9f6 RDI: 00000000ffffff9c
RBP: 00000000004be9f6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fff3e111a9f R14: 00007fb12a3a7300 R15: 0000000000022000

================================
WARNING: inconsistent lock state
5.12.0-rc6-syzkaller #0 Not tainted
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
syz-executor.3/23859 [HC0[0]:SC1[1]:HE0:SE0] takes:
ffffffff8bf7c8d8 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:541 [inline]
ffffffff8bf7c8d8 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:706 [inline]
ffffffff8bf7c8d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3830 [inline]
ffffffff8bf7c8d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq.cold+0x2b9/0x11dd kernel/rcu/tree.c:2650
{IN-HARDIRQ-W} state was registered at:
  lock_acquire kernel/locking/lockdep.c:5510 [inline]
  lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5475
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159
  rcu_report_exp_cpu_mult+0x73/0x3a0 kernel/rcu/tree_exp.h:237
  flush_smp_call_function_queue+0x34b/0x640 kernel/smp.c:426
  __sysvec_call_function_single+0x95/0x3d0 arch/x86/kernel/smp.c:248
  sysvec_call_function_single+0x8e/0xc0 arch/x86/kernel/smp.c:243
  asm_sysvec_call_function_single+0x12/0x20 arch/x86/include/asm/idtentry.h:640
  __memset+0x2b/0x30 arch/x86/lib/memset_64.S:41
  kasan_unpoison mm/kasan/shadow.c:132 [inline]
  kasan_unpoison+0x3a/0x60 mm/kasan/shadow.c:109
  __kasan_slab_alloc+0x37/0x90 mm/kasan/common.c:456
  kasan_slab_alloc include/linux/kasan.h:223 [inline]
  slab_post_alloc_hook mm/slab.h:516 [inline]
  slab_alloc_node mm/slub.c:2907 [inline]
  slab_alloc mm/slub.c:2915 [inline]
  kmem_cache_alloc_trace+0x14a/0x2a0 mm/slub.c:2932
  kmalloc include/linux/slab.h:554 [inline]
  kzalloc include/linux/slab.h:684 [inline]
  alloc_bprm+0x51/0x8f0 fs/exec.c:1500
  kernel_execve+0x55/0x460 fs/exec.c:1940
  call_usermodehelper_exec_async+0x2de/0x580 kernel/umh.c:110
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
irq event stamp: 13244853
hardirqs last  enabled at (13244852): [<ffffffff89200d42>] asm_sysvec_irq_work+0x12/0x20 arch/x86/include/asm/idtentry.h:658
hardirqs last disabled at (13244853): [<ffffffff890320bb>] sysvec_apic_timer_interrupt+0xb/0xc0 arch/x86/kernel/apic/apic.c:1100
softirqs last  enabled at (0): [<ffffffff8143065b>] copy_process+0x1d4b/0x71a0 kernel/fork.c:2062
softirqs last disabled at (519): [<ffffffff81451eb4>] invoke_softirq kernel/softirq.c:221 [inline]
softirqs last disabled at (519): [<ffffffff81451eb4>] __irq_exit_rcu kernel/softirq.c:422 [inline]
softirqs last disabled at (519): [<ffffffff81451eb4>] irq_exit_rcu+0x134/0x200 kernel/softirq.c:434

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rcu_node_0);
  <Interrupt>
    lock(rcu_node_0);

 *** DEADLOCK ***

2 locks held by syz-executor.3/23859:
 #0: ffffffff8bf74320 (rcu_read_lock){....}-{1:2}, at: path_init+0x67d/0x1910 fs/namei.c:2302
 #1: ffffffff8bf7c8d8 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:541 [inline]
 #1: ffffffff8bf7c8d8 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:706 [inline]
 #1: ffffffff8bf7c8d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3830 [inline]
 #1: ffffffff8bf7c8d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq.cold+0x2b9/0x11dd kernel/rcu/tree.c:2650

stack backtrace:
CPU: 1 PID: 23859 Comm: syz-executor.3 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 print_usage_bug kernel/locking/lockdep.c:202 [inline]
 valid_state kernel/locking/lockdep.c:3818 [inline]
 mark_lock_irq kernel/locking/lockdep.c:4021 [inline]
 mark_lock.cold+0x61/0x8e kernel/locking/lockdep.c:4478
 mark_held_locks+0x9f/0xe0 kernel/locking/lockdep.c:4079
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4097 [inline]
 lockdep_hardirqs_on_prepare kernel/locking/lockdep.c:4165 [inline]
 lockdep_hardirqs_on_prepare+0x135/0x400 kernel/locking/lockdep.c:4117
 trace_hardirqs_on+0x5b/0x1c0 kernel/trace/trace_preemptirq.c:49
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:199
Code: 0f 1f 44 00 00 55 48 8b 74 24 08 48 89 fd 48 83 c7 18 e8 1e 0c 54 f8 48 89 ef e8 46 c2 54 f8 e8 c1 4b 74 f8 fb bf 01 00 00 00 <e8> 46 90 48 f8 65 8b 05 ef 5a fc 76 85 c0 74 02 5d c3 e8 4b b0 fa
RSP: 0018:ffffc90000dc0e10 EFLAGS: 00000202
RAX: 0000000000ca14c4 RBX: ffffffff877aa990 RCX: 1ffffffff1b89d19
RDX: 0000000000000000 RSI: 0000000000000101 RDI: 0000000000000001
RBP: ffff8880b9d241c0 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8179e0b8 R11: 0000000000000000 R12: ffffc90000dc0ea8
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880b9d241c0
 expire_timers kernel/time/timer.c:1475 [inline]
 __run_timers.part.0+0x66c/0xa50 kernel/time/timer.c:1745
 __run_timers kernel/time/timer.c:1726 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1758
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu kernel/softirq.c:422 [inline]
 irq_exit_rcu+0x134/0x200 kernel/softirq.c:434
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:unwind_next_frame+0xed4/0x1ce0 arch/x86/kernel/unwind_orc.c:611
Code: c0 74 08 3c 03 0f 8e 90 0a 00 00 41 3b 2e 0f 84 b9 05 00 00 bf 01 00 00 00 e8 88 9c 1b 00 b8 01 00 00 00 65 8b 15 2c 67 cf 7e <85> d2 0f 85 aa f1 ff ff e8 86 bc cd ff e9 a0 f1 ff ff 4c 8b 7c 24
RSP: 0018:ffffc90003597388 EFLAGS: 00000297
RAX: 0000000000000001 RBX: 1ffff920006b2e79 RCX: 0000000000000000
RDX: 0000000080000000 RSI: ffffc90003597480 RDI: 0000000000000001
RBP: ffffc900035974b0 R08: ffffffff8e3c80e0 R09: 0000000000000001
R10: fffff520006b2ea1 R11: 0000000000084087 R12: ffffc90003590000
R13: ffffc900035974e5 R14: ffffc900035974b0 R15: ffffc900035974e4
 __unwind_start+0x51b/0x800 arch/x86/kernel/unwind_orc.c:699
 unwind_start arch/x86/include/asm/unwind.h:60 [inline]
 arch_stack_walk+0x5c/0xe0 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:427 [inline]
 ____kasan_kmalloc mm/kasan/common.c:506 [inline]
 ____kasan_kmalloc mm/kasan/common.c:465 [inline]
 __kasan_kmalloc+0x99/0xc0 mm/kasan/common.c:515
 kmalloc include/linux/slab.h:554 [inline]
 proc_self_get_link+0x187/0x1f0 fs/proc/self.c:22
 pick_link fs/namei.c:1738 [inline]
 step_into+0x1483/0x1c80 fs/namei.c:1799
 walk_component+0x171/0x6a0 fs/namei.c:1949
 link_path_walk.part.0+0x712/0xc90 fs/namei.c:2270
 link_path_walk fs/namei.c:2195 [inline]
 path_openat+0x25a/0x27e0 fs/namei.c:3496
 do_filp_open+0x190/0x3d0 fs/namei.c:3527
 do_sys_openat2+0x16d/0x420 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_openat fs/open.c:1219 [inline]
 __se_sys_openat fs/open.c:1214 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1214
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x419544
Code: 84 00 00 00 00 00 44 89 54 24 0c e8 96 f9 ff ff 44 8b 54 24 0c 44 89 e2 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 89 44 24 0c e8 c8 f9 ff ff 8b 44
RSP: 002b:00007fb12a3a70b0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000419544
RDX: 0000000000000000 RSI: 00000000004be9f6 RDI: 00000000ffffff9c
RBP: 00000000004be9f6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fff3e111a9f R14: 00007fb12a3a7300 R15: 0000000000022000
softirq: huh, entered softirq 1 TIMER ffffffff81637600 with preempt_count 00000100, exited with 00000101?