bisecting fixing commit since 4ba8e26127c393c32776dff6d79c5b82de6dc542 building syzkaller on 5da9499f431225d763a8dbb3410ca4856cb865b9 testing commit 4ba8e26127c393c32776dff6d79c5b82de6dc542 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 00fac7216bd8f6dcd4573e70ce506a8439048c7760042cc611f357150df10a27 run #0: crashed: unregister_netdevice: waiting for DEV to become free run #1: crashed: unregister_netdevice: waiting for DEV to become free run #2: crashed: unregister_netdevice: waiting for DEV to become free run #3: crashed: unregister_netdevice: waiting for DEV to become free run #4: crashed: unregister_netdevice: waiting for DEV to become free run #5: crashed: unregister_netdevice: waiting for DEV to become free run #6: crashed: unregister_netdevice: waiting for DEV to become free run #7: crashed: unregister_netdevice: waiting for DEV to become free run #8: crashed: unregister_netdevice: waiting for DEV to become free run #9: crashed: unregister_netdevice: waiting for DEV to become free run #10: crashed: unregister_netdevice: waiting for DEV to become free run #11: crashed: unregister_netdevice: waiting for DEV to become free run #12: crashed: unregister_netdevice: waiting for DEV to become free run #13: crashed: unregister_netdevice: waiting for DEV to become free run #14: crashed: unregister_netdevice: waiting for DEV to become free run #15: crashed: INFO: rcu detected stall in corrupted run #16: crashed: INFO: rcu detected stall in chrdev_open run #17: crashed: INFO: rcu detected stall in corrupted run #18: crashed: unregister_netdevice: waiting for DEV to become free run #19: crashed: INFO: rcu detected stall in chrdev_open testing current HEAD eb045674aab31aa55a4f9aec27cce36e3d946a21 testing commit eb045674aab31aa55a4f9aec27cce36e3d946a21 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 30ca60d8609382e3801a3cae44862063b00d77273d2e38efe48b648948949b42 run #0: crashed: unregister_netdevice: waiting for DEV to become free run #1: crashed: unregister_netdevice: waiting for DEV to become free run #2: crashed: unregister_netdevice: waiting for DEV to become free run #3: crashed: unregister_netdevice: waiting for DEV to become free run #4: crashed: unregister_netdevice: waiting for DEV to become free run #5: crashed: unregister_netdevice: waiting for DEV to become free run #6: crashed: unregister_netdevice: waiting for DEV to become free run #7: crashed: INFO: rcu detected stall in corrupted run #8: crashed: INFO: rcu detected stall in corrupted run #9: crashed: INFO: rcu detected stall in corrupted revisions tested: 2, total time: 30m4.119809775s (build: 19m35.163728211s, test: 9m47.355534189s) the crash still happens on HEAD commit msg: Linux 4.14.272 crash: INFO: rcu detected stall in corrupted hrtimer: interrupt took 34006 ns INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=1205, c=1204, q=143) INFO: rcu_sched detected stalls on CPUs/tasks: All QSes seen, last rcu_preempt kthread activity 10502 (4294952657-4294942155), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor249 R running task (detected by 1, t=10502 jiffies, g=411, c=410, q=2) 26864 8792 8324 0x00000000 All QSes seen, last rcu_sched kthread activity 10502 (4294952657-4294942155), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor249 R Call Trace: running task 27192 8797 8326 0x00000000 Call Trace: sched_show_task kernel/sched/core.c:5168 [inline] sched_show_task.cold.22+0x343/0x3a7 kernel/sched/core.c:5143 print_other_cpu_stall kernel/rcu/tree.c:1501 [inline] check_cpu_stall kernel/rcu/tree.c:1616 [inline] __rcu_pending kernel/rcu/tree.c:3390 [inline] rcu_pending kernel/rcu/tree.c:3452 [inline] rcu_check_callbacks.cold.59+0xcbc/0xd13 kernel/rcu/tree.c:2792 sched_show_task kernel/sched/core.c:5168 [inline] sched_show_task.cold.22+0x343/0x3a7 kernel/sched/core.c:5143 update_process_times+0x2a/0x60 kernel/time/timer.c:1591 print_other_cpu_stall kernel/rcu/tree.c:1501 [inline] check_cpu_stall kernel/rcu/tree.c:1616 [inline] __rcu_pending kernel/rcu/tree.c:3390 [inline] rcu_pending kernel/rcu/tree.c:3452 [inline] rcu_check_callbacks.cold.59+0xcbc/0xd13 kernel/rcu/tree.c:2792 tick_sched_handle.isra.5+0x6f/0x140 kernel/time/tick-sched.c:165 update_process_times+0x2a/0x60 kernel/time/timer.c:1591 tick_sched_timer+0x39/0xf0 kernel/time/tick-sched.c:1223 tick_sched_handle.isra.5+0x6f/0x140 kernel/time/tick-sched.c:165 tick_sched_timer+0x39/0xf0 kernel/time/tick-sched.c:1223 __run_hrtimer kernel/time/hrtimer.c:1223 [inline] __hrtimer_run_queues+0x279/0xad0 kernel/time/hrtimer.c:1287 __run_hrtimer kernel/time/hrtimer.c:1223 [inline] __hrtimer_run_queues+0x279/0xad0 kernel/time/hrtimer.c:1287 hrtimer_interrupt+0x1ae/0x600 kernel/time/hrtimer.c:1321 hrtimer_interrupt+0x1ae/0x600 kernel/time/hrtimer.c:1321 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1079 [inline] smp_apic_timer_interrupt+0x11f/0x5d0 arch/x86/kernel/apic/apic.c:1104 apic_timer_interrupt+0x9a/0xa0 arch/x86/entry/entry_64.S:793 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1079 [inline] smp_apic_timer_interrupt+0x11f/0x5d0 arch/x86/kernel/apic/apic.c:1104 apic_timer_interrupt+0x9a/0xa0 arch/x86/entry/entry_64.S:793 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x56/0x90 kernel/locking/spinlock.c:200 RSP: 0018:ffff8880aac177a0 EFLAGS: 00000282 RIP: 0010:save_stack_address arch/x86/kernel/stacktrace.c:30 [inline] RIP: 0010:save_stack_address+0x2c/0x60 arch/x86/kernel/stacktrace.c:15 ORIG_RAX: ffffffffffffff10 RSP: 0000:ffff8880907ef520 EFLAGS: 00000283 RAX: dffffc0000000000 RBX: ffff8880ba634380 RCX: 0000000000000000 ORIG_RAX: ffffffffffffff10 RDX: 1ffffffff11e1153 RSI: 0000000000000001 RDI: ffffffff88f08a98 RAX: 0000000000000001 RBX: ffff8880907ef5e0 RCX: 0000000000000002 RBP: ffff8880aac177a8 R08: 0000000000000001 R09: 0000000000000000 RDX: ffff8880907ef5f8 RSI: ffffffff817e13f2 RDI: ffff8880907ef5e0 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ac37c000 R13: dffffc0000000000 R14: ffff8880ac37c628 R15: ffff8880ac37c000 RBP: ffff8880907ef530 R08: 1ffff110120fdeb2 R09: ffff8880907ef578 R10: ffff8880907ef4f0 R11: ffff8880907ef59f R12: ffffffff817e13f2 rq_unlock_irq kernel/sched/sched.h:1766 [inline] __schedule+0x1621/0x1ee0 kernel/sched/core.c:3390 R13: 0000000000000000 R14: ffff8880aab00100 R15: ffff88809b49fc5f __save_stack_trace+0x61/0xd0 arch/x86/kernel/stacktrace.c:46 schedule+0x7f/0x1b0 kernel/sched/core.c:3431 tty_open+0x354/0x8e0 drivers/tty/tty_io.c:2028 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:551 chrdev_open+0x1e9/0x5b0 fs/char_dev.c:423 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb6f/0x2760 fs/namei.c:3569 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:536 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 do_filp_open+0x16b/0x220 fs/namei.c:3603 slab_post_alloc_hook mm/slab.h:442 [inline] slab_alloc mm/slab.c:3390 [inline] kmem_cache_alloc_trace+0x13b/0x3f0 mm/slab.c:3616 kmalloc include/linux/slab.h:488 [inline] tty_alloc_file drivers/tty/tty_io.c:186 [inline] tty_open+0x135/0x8e0 drivers/tty/tty_io.c:2015 chrdev_open+0x1e9/0x5b0 fs/char_dev.c:423 do_sys_open+0x1d0/0x350 fs/open.c:1081 do_dentry_open+0x3e4/0xde0 fs/open.c:777 SYSC_openat fs/open.c:1108 [inline] SyS_openat+0xf/0x20 fs/open.c:1102 vfs_open+0xfc/0x240 fs/open.c:888 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb do_last fs/namei.c:3428 [inline] path_openat+0xb6f/0x2760 fs/namei.c:3569 RIP: 0033:0x7f8d5a568ae9 RSP: 002b:00007f8d5a51a318 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f8d5a5f03e8 RCX: 00007f8d5a568ae9 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c do_filp_open+0x16b/0x220 fs/namei.c:3603 RBP: 00007f8d5a5f03e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 7974742f7665642f R13: 00007ffe74310b8f R14: 00007f8d5a51a400 R15: 0000000000022000 rcu_preempt kthread starved for 10502 jiffies! g1205 c1204 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0 rcu_preempt R running task 29720 8 2 0x80000000 do_sys_open+0x1d0/0x350 fs/open.c:1081 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3387 SYSC_openat fs/open.c:1108 [inline] SyS_openat+0xf/0x20 fs/open.c:1102 schedule+0x7f/0x1b0 kernel/sched/core.c:3431 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 schedule_timeout+0x41f/0xcc0 kernel/time/timer.c:1747 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f8d5a568ae9 RSP: 002b:00007f8d5a51a318 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 rcu_gp_kthread+0xb69/0x1df0 kernel/rcu/tree.c:2255 RAX: ffffffffffffffda RBX: 00007f8d5a5f03e8 RCX: 00007f8d5a568ae9 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c kthread+0x338/0x400 kernel/kthread.c:232 RBP: 00007f8d5a5f03e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 7974742f7665642f R13: 00007ffe74310b8f R14: 00007f8d5a51a400 R15: 0000000000022000 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 rcu_sched kthread starved for 10502 jiffies! g411 c410 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 rcu_sched R running task 29752 9 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3387 schedule+0x7f/0x1b0 kernel/sched/core.c:3431 schedule_timeout+0x41f/0xcc0 kernel/time/timer.c:1747 rcu_gp_kthread+0xb69/0x1df0 kernel/rcu/tree.c:2255 kthread+0x338/0x400 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 sched: RT throttling activated