syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=736/1/0x4000000000000002 softirq=13243/13243 fqs=1 
	(t=10500 jiffies g=7081 q=140)
rcu: rcu_preempt kthread starved for 10498 jiffies! g7081 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    28984    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081
 schedule+0x181/0x210 kernel/sched/core.c:4155
 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline]
 rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 8597 Comm: blkid Not tainted 5.5.0-rc5-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:77 [inline]
 dump_stack+0x1fb/0x318 lib/dump_stack.c:118
 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271
 update_process_times+0x12d/0x180 kernel/time/timer.c:1726
 tick_sched_handle kernel/time/tick-sched.c:167 [inline]
 tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x48/0x50 kernel/kcov.c:197
Code: 80 13 00 00 83 fa 02 75 21 48 8b 91 88 13 00 00 48 8b 32 48 8d 7e 01 8b 89 84 13 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a <c3> 0f 1f 80 00 00 00 00 4c 8b 04 24 65 48 8b 04 25 c0 1d 02 00 65
RSP: 0018:ffffc900025f7640 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffffffff814897d3 RBX: 0000000000000000 RCX: ffff8880a25d65c0
RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea0002a13c40
RBP: ffffc900025f7668 R08: dffffc0000000000 R09: fffffbfff124248a
R10: fffffbfff124248a R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff8880a2f1d878
 free_thread_stack+0x168/0x590 kernel/fork.c:280
 release_task_stack kernel/fork.c:440 [inline]
 put_task_stack+0xa3/0x130 kernel/fork.c:451
 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256
 context_switch kernel/sched/core.c:3388 [inline]
 __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081
 preempt_schedule_irq+0xc1/0x140 kernel/sched/core.c:4338
 retint_kernel+0x1b/0x2b
RIP: 0010:lock_acquire+0x49/0x250 kernel/locking/lockdep.c:4477
Code: 75 c8 48 89 7d a8 48 ba 00 00 00 00 00 fc ff df 65 4c 8b 2c 25 c0 1d 02 00 49 81 c5 94 08 00 00 4c 89 eb 48 c1 eb 03 8a 04 13 <84> c0 0f 85 75 01 00 00 41 83 7d 00 00 0f 85 5b 01 00 00 44 89 75
RSP: 0018:ffffc900025f78c0 EFLAGS: 00000a07 ORIG_RAX: ffffffffffffff02
RAX: ffffffff835d8a00 RBX: 1ffff110144badca RCX: 0000000000000002
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff892d4bc0
RBP: ffffc900025f7918 R08: 0000000000000000 R09: 0000000000000000
R10: ffffed1012242ac7 R11: 0000000000000000 R12: 0000000000000002
R13: ffff8880a25d6e54 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire+0x2e/0x40 include/linux/rcupdate.h:208
 rcu_read_lock include/linux/rcupdate.h:617 [inline]
 smk_of_task_struct+0x22/0x1d0 security/smack/smack.h:407
 smack_task_getsecid+0x26/0x90 security/smack/smack_lsm.c:2098
 security_task_getsecid+0x75/0xc0 security/security.c:1655
 ima_file_mmap+0x6e/0x110 security/integrity/ima/ima_main.c:390
 security_mmap_file+0x1ae/0x1d0 security/security.c:1453
 vm_mmap_pgoff+0xca/0x1d0 mm/util.c:502
 vm_mmap+0x8d/0xb0 mm/util.c:525
 elf_map+0x1b8/0x310 fs/binfmt_elf.c:377
 load_elf_binary+0x1000/0x36c0 fs/binfmt_elf.c:982
 search_binary_handler+0x1a5/0x660 fs/exec.c:1658
 exec_binprm fs/exec.c:1701 [inline]
 __do_execve_file+0x1573/0x1cd0 fs/exec.c:1821
 do_execveat_common fs/exec.c:1867 [inline]
 do_execve fs/exec.c:1884 [inline]
 __do_sys_execve fs/exec.c:1960 [inline]
 __se_sys_execve fs/exec.c:1955 [inline]
 __x64_sys_execve+0x94/0xb0 fs/exec.c:1955
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f948e6a9207
Code: Bad RIP value.
RSP: 002b:00007fff68eb3448 EFLAGS: 00000206 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f948e6a9207
RDX: 0000000002308940 RSI: 00007fff68eb3540 RDI: 00007fff68eb4550
RBP: 0000000000625500 R08: 0000000000002165 R09: 0000000000002165
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000002308940
R13: 0000000000000007 R14: 0000000002304250 R15: 0000000000000005