bisecting fixing commit since f6d5cb9e2c06f7d583dd9f4f7cca21d13d78c32a building syzkaller on d5a3ae1f760e7cb2cd5a721d9645ae22eae114fe testing commit f6d5cb9e2c06f7d583dd9f4f7cca21d13d78c32a with gcc (GCC) 8.1.0 kernel signature: 9c3ecd90d398e948a4354892aa8d027dec389e216f22553cd6588f74755b5eff all runs: crashed: INFO: task hung in usb_bulk_msg testing current HEAD 0c88e405c97ed1828443b67891e6d4bb6e56cd4e testing commit 0c88e405c97ed1828443b67891e6d4bb6e56cd4e with gcc (GCC) 8.1.0 kernel signature: 1d2fa1475bf1c5ae4d060c1991790c6e4743d92e86cda007b161d319824f49e6 all runs: crashed: INFO: task hung in usb_bulk_msg revisions tested: 2, total time: 38m12.679138078s (build: 19m17.020226598s, test: 18m21.691130037s) the crash still happens on HEAD commit msg: Linux 4.19.160 crash: INFO: task hung in usb_bulk_msg usb usb7: usbfs: process 11635 (syz-executor.1) did not claim interface 0 before use usb usb7: usbfs: process 11625 (syz-executor.4) did not claim interface 0 before use usb usb7: usbfs: process 11678 (syz-executor.4) did not claim interface 0 before use INFO: task syz-executor.3:11752 blocked for more than 140 seconds. Not tainted 4.19.160-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D27752 11752 5954 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common+0x3fb/0x5d0 kernel/sched/completion.c:115 wait_for_completion_timeout+0xe/0x10 kernel/sched/completion.c:155 usb_start_wait_urb+0x12f/0x280 drivers/usb/core/message.c:62 usb_bulk_msg+0x1d4/0x610 drivers/usb/core/message.c:253 proc_bulk+0x4e5/0x630 drivers/usb/core/devio.c:1206 usbdev_do_ioctl+0x1191/0x28d0 drivers/usb/core/devio.c:2430 usbdev_ioctl+0x9/0x10 drivers/usb/core/devio.c:2580 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45d5b9 Code: Bad RIP value. RSP: 002b:00007f811859bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000001aa80 RCX: 000000000045d5b9 RDX: 0000000020000000 RSI: 00000000c0185502 RDI: 0000000000000003 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffca048f28f R14: 00007f811859c9c0 R15: 000000000118cf4c Showing all locks held in the system: 1 lock held by khungtaskd/1092: #0: 00000000c27dbd68 (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4442 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1092 Comm: khungtaskd Not tainted 4.19.160-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x17c/0x22a lib/dump_stack.c:118 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf5/0x119 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x5c3/0xb40 kernel/hung_task.c:287 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7 Comm: kworker/u4:0 Not tainted 4.19.160-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:mark_lock+0xa6/0x12f0 kernel/locking/lockdep.c:3105 Code: 69 e0 50 01 00 00 49 81 ec 50 01 00 00 49 81 c4 80 88 cb 89 49 8d 7c 24 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 05 0e 00 00 4d 85 6c 24 30 74 58 b8 01 00 00 00 RSP: 0018:ffff8881f56bfa38 EFLAGS: 00000806 RAX: dffffc0000000000 RBX: ffff8881f56b2a98 RCX: 1ffff1103ead6557 RDX: 1ffffffff1397878 RSI: ffff8881f56b2a98 RDI: ffffffff89cbc3c0 RBP: ffff8881f56bfa80 R08: ffff8881f56b2ab8 R09: 0000000000000002 R10: ffff8881f56b2a98 R11: ffff8881f56b2a34 R12: ffffffff89cbc390 R13: 0000000000000100 R14: 0000000000000008 R15: ffff8881f56b21c0 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f40b8db3000 CR3: 000000000846d004 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_acquire+0x764/0x47c0 kernel/locking/lockdep.c:3376 lock_acquire+0x180/0x3a0 kernel/locking/lockdep.c:3907 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: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