bisecting fixing commit since 4fa640dc52302b5e62b01b05c755b055549633ae
building syzkaller on d88894e6773ab63ac8b3f4b2edbae88290aaf0d6
testing commit 4fa640dc52302b5e62b01b05c755b055549633ae with gcc (GCC) 8.1.0
kernel signature: b34f5cc65c4946a17e0b58f3eeee3f02706580446ecada4fd9499399153b7a9f
run #0: crashed: INFO: rcu detected stall in do_idle
run #1: crashed: INFO: rcu detected stall in do_idle
run #2: crashed: INFO: rcu detected stall in smp_call_function
run #3: crashed: INFO: rcu detected stall in corrupted
run #4: crashed: INFO: rcu detected stall in do_idle
run #5: crashed: BUG: soft lockup in do_idle
run #6: crashed: BUG: soft lockup in mutex_spin_on_owner
run #7: crashed: no output from test machine
run #8: crashed: no output from test machine
run #9: crashed: INFO: rcu detected stall in corrupted
testing current HEAD c2e7554e1b85935d962127efa3c2a76483b0b3b6
testing commit c2e7554e1b85935d962127efa3c2a76483b0b3b6 with gcc (GCC) 8.1.0
kernel signature: 3c149fc3e9c609df12b7fc7f17c847150160f2a0ab4ceb8e56c0849428822966
run #0: crashed: INFO: rcu detected stall in newfstat
run #1: crashed: INFO: rcu detected stall in do_idle
run #2: crashed: INFO: rcu detected stall in do_idle
run #3: crashed: INFO: rcu detected stall in do_idle
run #4: crashed: INFO: rcu detected stall in do_idle
run #5: crashed: BUG: soft lockup in do_idle
run #6: crashed: INFO: rcu detected stall in do_idle
run #7: crashed: INFO: rcu detected stall in task_work_run
run #8: crashed: INFO: rcu detected stall in do_idle
run #9: crashed: INFO: rcu detected stall in do_idle
revisions tested: 2, total time: 25m16.795606004s (build: 9m49.403151467s, test: 14m49.084531229s)
the crash still happens on HEAD
commit msg: Merge tag 'gfs2-v5.10-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
crash: INFO: rcu detected stall in do_idle
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (3 ticks this GP) idle=b42/0/0x1 softirq=10336/10336 fqs=0 
	(t=12276 jiffies g=3793 q=406)
rcu: rcu_preempt kthread starved for 12276 jiffies! g3793 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:14328 pid:   10 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3774 [inline]
 __schedule+0x404/0x890 kernel/sched/core.c:4523
 schedule+0x38/0xe0 kernel/sched/core.c:4601
 schedule_timeout+0x1be/0x2e0 kernel/time/timer.c:1871
 rcu_gp_fqs_loop kernel/rcu/tree.c:1925 [inline]
 rcu_gp_kthread+0x707/0xc60 kernel/rcu/tree.c:2099
 kthread+0x145/0x170 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.10.0-rc4-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+0xa3/0xc8 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold.8+0x53/0x6d lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0xd5/0xf0 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0xa2/0xce kernel/rcu/tree_stall.h:331
 print_cpu_stall kernel/rcu/tree_stall.h:563 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:637 [inline]
 rcu_pending kernel/rcu/tree.c:3694 [inline]
 rcu_sched_clock_irq.cold.95+0x61/0x5d5 kernel/rcu/tree.c:2567
 update_process_times+0x50/0x80 kernel/time/timer.c:1709
 tick_sched_handle.isra.24+0x1a/0x50 kernel/time/tick-sched.c:176
 tick_sched_timer+0x6c/0x80 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x1e3/0x4f0 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0xf9/0x210 kernel/time/hrtimer.c:1645
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x8e/0x290 arch/x86/kernel/apic/apic.c:1097
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
 sysvec_apic_timer_interrupt+0xcc/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: 5b c3 65 48 8b 04 25 c0 7e 01 00 f0 80 48 02 20 48 8b 00 a8 08 75 c3 e9 7c ff ff ff e9 07 00 00 00 0f 00 2d bc 29 55 00 fb f4 <c3> 90 e9 07 00 00 00 0f 00 2d ac 29 55 00 f4 c3 cc cc e8 bb 07 ff
RSP: 0018:ffffc90000cd3e68 EFLAGS: 00000282
RAX: 0000000000064c51 RBX: ffff888102ae4800 RCX: 00000000ffffffff
RDX: 0000000000000000 RSI: ffffffff83f2dba3 RDI: ffffffff83f6ab36
RBP: ffffffff84529b80 R08: 0000000000000001 R09: 0000000000000001
R10: ffff88813bd2c404 R11: ffff88813bd2c3e4 R12: 0000000000000001
R13: ffff888100e60c64 R14: 0000000000000001 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:150 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
 acpi_idle_do_entry+0x50/0x90 drivers/acpi/processor_idle.c:517
 acpi_idle_enter+0xa0/0xf0 drivers/acpi/processor_idle.c:648
 cpuidle_enter_state+0x94/0x520 drivers/cpuidle/cpuidle.c:237
 cpuidle_enter+0x24/0x40 drivers/cpuidle/cpuidle.c:351
 call_cpuidle kernel/sched/idle.c:132 [inline]
 cpuidle_idle_call kernel/sched/idle.c:213 [inline]
 do_idle+0x2dc/0x350 kernel/sched/idle.c:273
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:369
 secondary_startup_64_no_verify+0xb0/0xbb