bisecting fixing commit since d7e78d08fa77acdea351c8f628f49ca9a0e1029a building syzkaller on 816e0689d7d9d8321f8bf360740f0e516aee15ca testing commit d7e78d08fa77acdea351c8f628f49ca9a0e1029a with gcc (GCC) 8.1.0 kernel signature: ed5931afa4476141c885fc61eeea4a1bbaabace11af423faeb2c730e214b6759 run #0: crashed: WARNING: ODEBUG bug in bt_host_release run #1: crashed: KASAN: use-after-free Read in __queue_work run #2: crashed: KASAN: use-after-free Read in __queue_work run #3: crashed: WARNING: ODEBUG bug in bt_host_release run #4: crashed: WARNING: ODEBUG bug in bt_host_release run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK testing current HEAD 2d2791fce891fc20709232d49a6bae075b9a77f8 testing commit 2d2791fce891fc20709232d49a6bae075b9a77f8 with gcc (GCC) 8.1.0 kernel signature: 47ca7e5f7971df33780f63c2af34d9a48886822db9b42ea7b8a151125b1bf1c6 run #0: crashed: WARNING: ODEBUG bug in bt_host_release run #1: crashed: WARNING: ODEBUG bug in bt_host_release run #2: crashed: INFO: task hung in hci_req_sync run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK reproducer seems to be flaky Reproducer flagged being flaky revisions tested: 2, total time: 38m46.282103097s (build: 16m18.731664577s, test: 21m53.634008949s) the crash still happens on HEAD commit msg: Linux 4.14.217 crash: INFO: task hung in hci_req_sync Bluetooth: hci1 command 0x0401 tx timeout Bluetooth: hci1 command 0x0401 tx timeout Bluetooth: hci1 command 0x0401 tx timeout Bluetooth: hci1 command 0x0401 tx timeout Bluetooth: hci1 command 0x0401 tx timeout INFO: task syz-executor.3:12066 blocked for more than 140 seconds. Not tainted 4.14.217-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29000 12066 9484 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 hci_req_sync+0x5b/0xb0 net/bluetooth/hci_request.c:284 hci_inquiry+0x57d/0x790 net/bluetooth/hci_core.c:1272 hci_sock_ioctl+0x199/0x600 net/bluetooth/hci_sock.c:1043 sock_do_ioctl+0x62/0xa0 net/socket.c:974 sock_ioctl+0x251/0x430 net/socket.c:1071 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x74/0x80 fs/ioctl.c:692 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45d5b9 RSP: 002b:00007fe3fd957c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000f2c0 RCX: 000000000045d5b9 RDX: 0000000020000200 RSI: 00000000800448f0 RDI: 0000000000000004 RBP: 000000000118d0c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118d08c R13: 00007ffc9b82967f R14: 00007fe3fd9589c0 R15: 000000000118d08c INFO: task syz-executor.2:12042 blocked for more than 140 seconds. Not tainted 4.14.217-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28344 12042 7440 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 hci_req_sync+0x5b/0xb0 net/bluetooth/hci_request.c:284 hci_inquiry+0x57d/0x790 net/bluetooth/hci_core.c:1272 hci_sock_ioctl+0x199/0x600 net/bluetooth/hci_sock.c:1043 sock_do_ioctl+0x62/0xa0 net/socket.c:974 sock_ioctl+0x251/0x430 net/socket.c:1071 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x74/0x80 fs/ioctl.c:692 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45d5b9 RSP: 002b:00007f69ae1eec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000f2c0 RCX: 000000000045d5b9 RDX: 0000000020000200 RSI: 00000000800448f0 RDI: 0000000000000004 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffe6227b13f R14: 00007f69ae1ef9c0 R15: 000000000118cf4c INFO: task syz-executor.5:12304 blocked for more than 140 seconds. Not tainted 4.14.217-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28344 12304 11986 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 hci_req_sync+0x5b/0xb0 net/bluetooth/hci_request.c:284 hci_inquiry+0x57d/0x790 net/bluetooth/hci_core.c:1272 hci_sock_ioctl+0x199/0x600 net/bluetooth/hci_sock.c:1043 sock_do_ioctl+0x62/0xa0 net/socket.c:974 sock_ioctl+0x251/0x430 net/socket.c:1071 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684 Bluetooth: hci1 command 0x0401 tx timeout SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x74/0x80 fs/ioctl.c:692 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45d5b9 RSP: 002b:00007fb98a64ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000f2c0 RCX: 000000000045d5b9 RDX: 0000000020000200 RSI: 00000000800448f0 RDI: 0000000000000004 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffe0c64e01f R14: 00007fb98a64b9c0 R15: 000000000118cf4c Showing all locks held in the system: 1 lock held by khungtaskd/1069: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4548 1 lock held by syz-executor.3/12066: #0: (&hdev->req_lock){+.+.}, at: [] hci_req_sync+0x5b/0xb0 net/bluetooth/hci_request.c:284 1 lock held by syz-executor.1/12034: #0: (&hdev->req_lock){+.+.}, at: [] hci_req_sync+0x5b/0xb0 net/bluetooth/hci_request.c:284 1 lock held by syz-executor.2/12042: #0: (&hdev->req_lock){+.+.}, at: [] hci_req_sync+0x5b/0xb0 net/bluetooth/hci_request.c:284 1 lock held by syz-executor.5/12304: #0: (&hdev->req_lock){+.+.}, at: [] hci_req_sync+0x5b/0xb0 net/bluetooth/hci_request.c:284 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1069 Comm: khungtaskd Not tainted 4.14.217-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x14b/0x1e7 lib/dump_stack.c:58 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf5/0x120 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:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x51b/0xa70 kernel/hung_task.c:274 kthread+0x338/0x400 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff866bf002