bisecting fixing commit since 125222814e7b8f84df767d6ab622aff2a6d2f234 building syzkaller on 8092f30df01f3443831725509ef5a3dae26122c0 testing commit 125222814e7b8f84df767d6ab622aff2a6d2f234 with gcc (GCC) 8.4.1 20210217 kernel signature: 9fdf486635dde2236974340dd7a6ad980ba7875231c0f6bdcf47b5034b12d42f run #0: crashed: INFO: rcu detected stall in corrupted run #1: crashed: INFO: rcu detected stall in corrupted run #2: crashed: INFO: rcu detected stall in chrdev_open run #3: crashed: INFO: rcu detected stall in corrupted run #4: crashed: INFO: rcu detected stall in chrdev_open run #5: crashed: INFO: rcu detected stall in chrdev_open run #6: crashed: INFO: rcu detected stall in chrdev_open run #7: crashed: INFO: rcu detected stall in corrupted run #8: crashed: INFO: rcu detected stall in chrdev_open run #9: crashed: INFO: rcu detected stall in chrdev_open run #10: crashed: INFO: rcu detected stall in chrdev_open run #11: crashed: INFO: rcu detected stall in corrupted run #12: crashed: INFO: rcu detected stall in chrdev_open run #13: crashed: INFO: rcu detected stall in corrupted run #14: crashed: INFO: rcu detected stall in chrdev_open run #15: crashed: INFO: rcu detected stall in chrdev_open run #16: crashed: INFO: rcu detected stall in chrdev_open run #17: crashed: INFO: rcu detected stall in corrupted run #18: crashed: INFO: rcu detected stall in chrdev_open run #19: crashed: INFO: rcu detected stall in corrupted testing current HEAD eb575cd5d7f60241d016fdd13a9e86d962093c9b testing commit eb575cd5d7f60241d016fdd13a9e86d962093c9b with gcc (GCC) 8.4.1 20210217 kernel signature: 118be811976a32986cf05cc62dc10cb5f6d59a112661736f612e8415a83d2cb0 run #0: crashed: INFO: rcu detected stall in chrdev_open run #1: crashed: INFO: rcu detected stall in chrdev_open run #2: crashed: INFO: rcu detected stall in chrdev_open run #3: crashed: INFO: rcu detected stall in chrdev_open run #4: crashed: INFO: rcu detected stall in corrupted run #5: crashed: INFO: rcu detected stall in corrupted run #6: crashed: INFO: rcu detected stall in chrdev_open run #7: crashed: INFO: rcu detected stall in corrupted run #8: crashed: INFO: rcu detected stall in chrdev_open run #9: crashed: INFO: rcu detected stall in corrupted revisions tested: 2, total time: 30m44.291181891s (build: 16m37.705130015s, test: 13m44.683087178s) the crash still happens on HEAD commit msg: Linux 4.19.195 crash: INFO: rcu detected stall in corrupted IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10068 rcu: (detected by 0, t=10503 jiffies, g=19749, q=1987) kworker/u4:10 R running task 27248 10068 2 0x80000000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 preempt_schedule_irq+0xb9/0x140 kernel/sched/core.c:3744 retint_kernel+0x1b/0x2d RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:lock_acquire+0x1f5/0x3a0 kernel/locking/lockdep.c:3911 Code: 00 00 00 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 99 01 00 00 48 83 3d 2f 93 4a 08 00 0f 84 1c 01 00 00 48 8b 7d c0 57 9d <0f> 1f 44 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 65 8b RSP: 0018:ffff888096f07cb0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffff88809ea34540 RCX: 1ffff11013d469c7 RDX: 1ffffffff1322499 RSI: 0000000000000000 RDI: 0000000000000286 RBP: ffff888096f07cf8 R08: ffff88809ea34e38 R09: 0000000000000002 R10: ffff88809ea34e18 R11: 0000000000000001 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88809ea34540 rcu_lock_acquire include/linux/rcupdate.h:242 [inline] rcu_read_lock include/linux/rcupdate.h:627 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline] batadv_nc_worker+0xec/0x630 net/batman-adv/network-coding.c:730 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2153 worker_thread+0x85/0xb60 kernel/workqueue.c:2296 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 kworker/u4:10 R running task 27248 10068 2 0x80000000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 preempt_schedule_irq+0xb9/0x140 kernel/sched/core.c:3744 retint_kernel+0x1b/0x2d RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:lock_acquire+0x1f5/0x3a0 kernel/locking/lockdep.c:3911 Code: 00 00 00 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 99 01 00 00 48 83 3d 2f 93 4a 08 00 0f 84 1c 01 00 00 48 8b 7d c0 57 9d <0f> 1f 44 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 65 8b RSP: 0018:ffff888096f07cb0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffff88809ea34540 RCX: 1ffff11013d469c7 RDX: 1ffffffff1322499 RSI: 0000000000000000 RDI: 0000000000000286 RBP: ffff888096f07cf8 R08: ffff88809ea34e38 R09: 0000000000000002 R10: ffff88809ea34e18 R11: 0000000000000001 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88809ea34540 rcu_lock_acquire include/linux/rcupdate.h:242 [inline] rcu_read_lock include/linux/rcupdate.h:627 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline] batadv_nc_worker+0xec/0x630 net/batman-adv/network-coding.c:730 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2153 worker_thread+0x85/0xb60 kernel/workqueue.c:2296 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 1825 jiffies! g19749 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29160 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 preempt_schedule_irq+0xb9/0x140 kernel/sched/core.c:3744 retint_kernel+0x1b/0x2d RIP: 0010:__read_once_size include/linux/compiler.h:261 [inline] RIP: 0010:rcu_gp_fqs_check_wake kernel/rcu/tree.c:2034 [inline] RIP: 0010:rcu_gp_kthread+0xc4a/0x23e0 kernel/rcu/tree.c:2202 Code: 0f ff ff ff 7c 08 84 c0 0f 85 d4 10 00 00 48 8b 85 30 ff ff ff bf 05 00 00 00 66 41 89 bd 62 04 00 00 0f b6 00 41 38 c4 7c 08 <84> c0 0f 85 91 10 00 00 41 0f bf 9d 60 04 00 00 89 d8 a8 02 0f 85 RSP: 0018:ffff8880b59bfd80 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff02 RAX: 0000000000000000 RBX: ffffffff89980a00 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000005 RBP: ffff8880b59bff00 R08: fffffbfff1330141 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffffffff89980a00 R14: 0000000100001400 R15: dffffc0000000000 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415