bisecting fixing commit since 5692097116094a4a7045abcc1dbc172dbdc5657e
building syzkaller on d850e9d08467726cd94b6a9caaf8090c594721ba
testing commit 5692097116094a4a7045abcc1dbc172dbdc5657e with gcc (GCC) 8.1.0
kernel signature: b2bfad3c04be0c020157c347cb3808f5ff81ccdc2d305666014dfc51a2bc3876
run #0: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #1: crashed: INFO: rcu detected stall in corrupted
run #2: crashed: INFO: rcu detected stall in corrupted
run #3: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #4: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #5: crashed: INFO: rcu detected stall in corrupted
run #6: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #7: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #8: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #9: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
testing current HEAD 3207316b3beec7e38e5dbe2f463df0cec71e0b97
testing commit 3207316b3beec7e38e5dbe2f463df0cec71e0b97 with gcc (GCC) 8.1.0
kernel signature: 83aa17a3892ac7563b641fdd11068323bd493e580c6660cf71286218e445f7f8
run #0: crashed: INFO: rcu detected stall in corrupted
run #1: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #2: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #3: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #4: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #5: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #6: crashed: INFO: rcu detected stall in corrupted
run #7: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #8: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl
run #9: crashed: INFO: rcu detected stall in corrupted
revisions tested: 2, total time: 27m15.615721855s (build: 17m35.601597791s, test: 8m42.471332228s)
the crash still happens on HEAD
commit msg: Linux 4.19.164
crash: INFO: rcu detected stall in corrupted
L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.
hrtimer: interrupt took 47379 ns
kvm: emulating exchange as write
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6632
rcu: 	(detected by 1, t=10503 jiffies, g=5593, q=261)
kworker/u4:5    R  running task    26616  6632      2 0x80000000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x78c/0x1c10 kernel/sched/core.c:3517
 preempt_schedule_notrace+0x70/0x140 kernel/sched/core.c:3715
 ___preempt_schedule_notrace+0x16/0x2d
 rcu_is_watching+0x23/0x30 kernel/rcu/tree.c:1026
 rcu_read_unlock include/linux/rcupdate.h:677 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:423 [inline]
 batadv_nc_worker+0x3a9/0x630 net/batman-adv/network-coding.c:730
 process_one_work+0x830/0x1670 kernel/workqueue.c:2155
 worker_thread+0x85/0xb60 kernel/workqueue.c:2298
 kthread+0x347/0x410 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
kworker/u4:5    R  running task    26616  6632      2 0x80000000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x78c/0x1c10 kernel/sched/core.c:3517
 preempt_schedule_notrace+0x70/0x140 kernel/sched/core.c:3715
 ___preempt_schedule_notrace+0x16/0x2d
 rcu_is_watching+0x23/0x30 kernel/rcu/tree.c:1026
 rcu_read_unlock include/linux/rcupdate.h:677 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:423 [inline]
 batadv_nc_worker+0x3a9/0x630 net/batman-adv/network-coding.c:730
 process_one_work+0x830/0x1670 kernel/workqueue.c:2155
 worker_thread+0x85/0xb60 kernel/workqueue.c:2298
 kthread+0x347/0x410 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
rcu: rcu_preempt kthread starved for 10520 jiffies! g5593 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29208    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x78c/0x1c10 kernel/sched/core.c:3517
 schedule+0x7f/0x1b0 kernel/sched/core.c:3561
 schedule_timeout+0x3ab/0xe00 kernel/time/timer.c:1818
 rcu_gp_kthread+0xce6/0x23d0 kernel/rcu/tree.c:2202
 kthread+0x347/0x410 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415