./strace-static-x86_64 -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f ./syz-executor1030511792 <...> Warning: Permanently added '10.128.0.146' (ED25519) to the list of known hosts. execve("./syz-executor1030511792", ["./syz-executor1030511792"], 0x7ffd6b428750 /* 10 vars */) = 0 brk(NULL) = 0x55555555c000 brk(0x55555555cd00) = 0x55555555cd00 arch_prctl(ARCH_SET_FS, 0x55555555c380) = 0 set_tid_address(0x55555555c650) = 5065 set_robust_list(0x55555555c660, 24) = 0 rseq(0x55555555cca0, 0x20, 0, 0x53053053) = 0 prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0 readlink("/proc/self/exe", "/root/syz-executor1030511792", 4096) = 28 getrandom("\xdf\x56\xe9\x2a\x7c\x6f\x29\x7c", 8, GRND_NONBLOCK) = 8 brk(NULL) = 0x55555555cd00 brk(0x55555557dd00) = 0x55555557dd00 brk(0x55555557e000) = 0x55555557e000 mprotect(0x7f440d010000, 16384, PROT_READ) = 0 mmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000 mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000 mmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000 unshare(CLONE_NEWPID) = 0 clone(child_stack=NULL, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD./strace-static-x86_64: Process 5066 attached , child_tidptr=0x55555555c650) = 5066 [pid 5066] set_robust_list(0x55555555c660, 24) = 0 [pid 5066] mount(NULL, "/sys/fs/fuse/connections", "fusectl", 0, NULL) = -1 EBUSY (Device or resource busy) [pid 5066] prctl(PR_SET_PDEATHSIG, SIGKILL) = 0 [pid 5066] setsid() = 1 [pid 5066] prlimit64(0, RLIMIT_AS, {rlim_cur=204800*1024, rlim_max=204800*1024}, NULL) = 0 [pid 5066] prlimit64(0, RLIMIT_MEMLOCK, {rlim_cur=32768*1024, rlim_max=32768*1024}, NULL) = 0 [pid 5066] prlimit64(0, RLIMIT_FSIZE, {rlim_cur=139264*1024, rlim_max=139264*1024}, NULL) = 0 [pid 5066] prlimit64(0, RLIMIT_STACK, {rlim_cur=1024*1024, rlim_max=1024*1024}, NULL) = 0 [pid 5066] prlimit64(0, RLIMIT_CORE, {rlim_cur=131072*1024, rlim_max=131072*1024}, NULL) = 0 [pid 5066] prlimit64(0, RLIMIT_NOFILE, {rlim_cur=256, rlim_max=256}, NULL) = 0 [pid 5066] unshare(CLONE_NEWNS) = 0 [pid 5066] mount(NULL, "/", NULL, MS_REC|MS_PRIVATE, NULL) = 0 [pid 5066] unshare(CLONE_NEWIPC) = 0 [pid 5066] unshare(CLONE_NEWCGROUP) = 0 [pid 5066] unshare(CLONE_NEWUTS) = 0 [pid 5066] unshare(CLONE_SYSVSEM) = 0 [pid 5066] openat(AT_FDCWD, "/proc/sys/kernel/shmmax", O_WRONLY|O_CLOEXEC) = 3 [pid 5066] write(3, "16777216", 8) = 8 [pid 5066] close(3) = 0 [pid 5066] openat(AT_FDCWD, "/proc/sys/kernel/shmall", O_WRONLY|O_CLOEXEC) = 3 [pid 5066] write(3, "536870912", 9) = 9 [pid 5066] close(3) = 0 [pid 5066] openat(AT_FDCWD, "/proc/sys/kernel/shmmni", O_WRONLY|O_CLOEXEC) = 3 [pid 5066] write(3, "1024", 4) = 4 [pid 5066] close(3) = 0 [pid 5066] openat(AT_FDCWD, "/proc/sys/kernel/msgmax", O_WRONLY|O_CLOEXEC) = 3 [pid 5066] write(3, "8192", 4) = 4 [pid 5066] close(3) = 0 [pid 5066] openat(AT_FDCWD, "/proc/sys/kernel/msgmni", O_WRONLY|O_CLOEXEC) = 3 [pid 5066] write(3, "1024", 4) = 4 [pid 5066] close(3) = 0 [pid 5066] openat(AT_FDCWD, "/proc/sys/kernel/msgmnb", O_WRONLY|O_CLOEXEC) = 3 [pid 5066] write(3, "1024", 4) = 4 [pid 5066] close(3) = 0 [pid 5066] openat(AT_FDCWD, "/proc/sys/kernel/sem", O_WRONLY|O_CLOEXEC) = 3 [pid 5066] write(3, "1024 1048576 500 1024", 21) = 21 [pid 5066] close(3) = 0 [pid 5066] getpid() = 1 [pid 5066] capget({version=_LINUX_CAPABILITY_VERSION_3, pid=1}, {effective=1<vb2q_lock){+.+.}-{3:3}, at: vb2_video_unregister_device+0x15f/0x230 [ 70.193411][ T8] [ 70.193411][ T8] but task is already holding lock: [ 70.200753][ T8] ffff888022964b78 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: usbtv_video_free+0x22/0x70 [ 70.210047][ T8] [ 70.210047][ T8] other info that might help us debug this: [ 70.218107][ T8] Possible unsafe locking scenario: [ 70.218107][ T8] [ 70.225795][ T8] CPU0 [ 70.229055][ T8] ---- [ 70.232309][ T8] lock(&usbtv->vb2q_lock); [ 70.236877][ T8] lock(&usbtv->vb2q_lock); [ 70.241443][ T8] [ 70.241443][ T8] *** DEADLOCK *** [ 70.241443][ T8] [ 70.249561][ T8] May be due to missing lock nesting notation [ 70.249561][ T8] [ 70.257862][ T8] 7 locks held by kworker/0:0/8: [ 70.262781][ T8] #0: ffff88801bad1d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x1420 [ 70.274089][ T8] #1: ffffc900000d7d20 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x1420 [ 70.285908][ T8] #2: ffff888023c22190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1fe/0x50f0 [ 70.294783][ T8] #3: ffff88802955d190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x103/0x950 [ 70.303991][ T8] #4: ffff88807a3cc160 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xce/0x7c0 [ 70.314502][ T8] #5: ffff888022964b78 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: usbtv_video_free+0x22/0x70 [ 70.324229][ T8] #6: ffff888022964ae8 (&usbtv->v4l2_lock){+.+.}-{3:3}, at: usbtv_video_free+0x33/0x70 [ 70.333956][ T8] [ 70.333956][ T8] stack backtrace: [ 70.339830][ T8] CPU: 0 PID: 8 Comm: kworker/0:0 Not tainted 6.8.0-rc5-syzkaller #0 [ 70.347966][ T8] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 [ 70.358004][ T8] Workqueue: usb_hub_wq hub_event [ 70.363021][ T8] Call Trace: [ 70.366287][ T8] [ 70.369204][ T8] dump_stack_lvl+0x1e7/0x2e0 [ 70.373889][ T8] ? __pfx_dump_stack_lvl+0x10/0x10 [ 70.379082][ T8] ? print_deadlock_bug+0x479/0x620 [ 70.384350][ T8] ? _find_first_zero_bit+0xd4/0x100 [ 70.389621][ T8] validate_chain+0x15c0/0x58e0 [ 70.394460][ T8] ? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10 [ 70.400781][ T8] ? __pfx_validate_chain+0x10/0x10 [ 70.405967][ T8] ? _raw_spin_unlock_irqrestore+0xdd/0x140 [ 70.411847][ T8] ? __pfx__raw_spin_unlock_irqrestore+0x10/0x10 [ 70.418163][ T8] ? stack_depot_save_flags+0x4ca/0x5c0 [ 70.423698][ T8] ? kobject_put+0x22f/0x480 [ 70.428278][ T8] ? kasan_save_track+0x51/0x80 [ 70.433125][ T8] ? kasan_save_track+0x3f/0x80 [ 70.437962][ T8] ? kasan_save_free_info+0x4e/0x60 [ 70.443145][ T8] ? poison_slab_object+0xa6/0xe0 [ 70.448159][ T8] ? __kasan_slab_free+0x34/0x70 [ 70.453081][ T8] ? kfree+0x14a/0x380 [ 70.457134][ T8] ? kobject_put+0x22f/0x480 [ 70.461725][ T8] ? cleanup_glue_dir+0x1ac/0x210 [ 70.466740][ T8] ? device_del+0x848/0xa30 [ 70.471248][ T8] ? device_unregister+0x20/0xc0 [ 70.476168][ T8] ? vb2_video_unregister_device+0xc6/0x230 [ 70.482044][ T8] ? usbtv_video_free+0x47/0x70 [ 70.486880][ T8] ? usbtv_disconnect+0x6d/0xd0 [ 70.491733][ T8] ? usb_unbind_interface+0x1d4/0x850 [ 70.497097][ T8] ? mark_lock+0x9a/0x350 [ 70.501412][ T8] ? worker_thread+0xa5f/0x1000 [ 70.506261][ T8] __lock_acquire+0x1345/0x1fd0 [ 70.511114][ T8] lock_acquire+0x1e3/0x530 [ 70.515606][ T8] ? vb2_video_unregister_device+0x15f/0x230 [ 70.521574][ T8] ? __pfx_lock_acquire+0x10/0x10 [ 70.526590][ T8] ? __pfx___might_resched+0x10/0x10 [ 70.531865][ T8] ? __pfx___mutex_unlock_slowpath+0x10/0x10 [ 70.537838][ T8] __mutex_lock+0x136/0xd70 [ 70.542330][ T8] ? vb2_video_unregister_device+0x15f/0x230 [ 70.548297][ T8] ? device_del+0x898/0xa30 [ 70.552786][ T8] ? vb2_video_unregister_device+0x15f/0x230 [ 70.558753][ T8] ? __pfx___mutex_lock+0x10/0x10 [ 70.563767][ T8] ? lockdep_hardirqs_on+0x98/0x140 [ 70.568957][ T8] vb2_video_unregister_device+0x15f/0x230 [ 70.574749][ T8] usbtv_video_free+0x47/0x70 [ 70.579409][ T8] usbtv_disconnect+0x6d/0xd0 [ 70.584078][ T8] usb_unbind_interface+0x1d4/0x850 [ 70.589269][ T8] ? kernfs_remove_by_name_ns+0x11b/0x160 [ 70.594975][ T8] ? __pfx_usb_unbind_interface+0x10/0x10 [ 70.600682][ T8] device_release_driver_internal+0x503/0x7c0 [ 70.606740][ T8] bus_remove_device+0x34f/0x420 [ 70.611669][ T8] device_del+0x580/0xa30 [ 70.615985][ T8] ? kfree+0x14a/0x380 [ 70.620047][ T8] ? __pfx_device_del+0x10/0x10 [ 70.624881][ T8] ? kobject_put+0x44a/0x480 [ 70.629464][ T8] usb_disable_device+0x3bf/0x850 [ 70.634480][ T8] usb_disconnect+0x340/0x950 [ 70.639146][ T8] hub_event+0x1e62/0x50f0 [ 70.643559][ T8] ? debug_object_deactivate+0x2d5/0x390 [ 70.649191][ T8] ? __pfx_hub_event+0x10/0x10 [ 70.653945][ T8] ? __pfx_lock_acquire+0x10/0x10 [ 70.658961][ T8] ? lockdep_hardirqs_on_prepare+0x43c/0x780 [ 70.665104][ T8] ? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10 [ 70.671426][ T8] ? process_scheduled_works+0x825/0x1420 [ 70.677135][ T8] process_scheduled_works+0x913/0x1420 [ 70.682725][ T8] ? __pfx_process_scheduled_works+0x10/0x10 [ 70.688698][ T8] ? assign_work+0x364/0x3d0 [ 70.693288][ T8] worker_thread+0xa5f/0x1000 [ 70.697962][ T8] ? __pfx_worker_thread+0x10/0x10 [ 70.703062][ T8] kthread+0x2ef/0x390 [ 70.707117][ T8] ? __pfx_worker_thread+0x10/0x10 [ 70.712217][ T8] ? __pfx_kthread+0x10/0x10 [ 70.716791][ T8] ret_from_fork+0x4b/0x80 [ 70.721195][ T8] ? __pfx_kthread+0x10/0x10 [ 70.725770][ T8] ret_from_fork_asm+0x1b/0x30 [ 70.730532][ T8] [pid 5066] +++ exited with 1 +++ --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=5066, si_uid=0, si_status=1, si_utime=0, si_stime=97 /* 0.97 s */} --- exit_group(0) = ? +++ exited with 0 +++