Hello, syzbot found the following issue on: HEAD commit: ed5551279c91 Merge 6.8-rc3 into usb-next git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing console output: https://syzkaller.appspot.com/x/log.txt?x=16940d7be80000 kernel config: https://syzkaller.appspot.com/x/.config?x=28a3704ea90ef255 dashboard link: https://syzkaller.appspot.com/bug?extid=3b1d4b3d5f7a358bf9a9 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14450a38180000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1603629fe80000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/10b543a7171a/disk-ed555127.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/dc10f27643e8/vmlinux-ed555127.xz kernel image: https://storage.googleapis.com/syzbot-assets/bb6389e754b9/bzImage-ed555127.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+3b1d4b3d5f7a358bf9a9@xxxxxxxxxxxxxxxxxxxxxxxxx usb 1-1: SerialNumber: syz usb 1-1: config 0 descriptor?? usbtv 1-1:0.0: Fushicai USBTV007 Audio-Video Grabber usb 1-1: USB disconnect, device number 2 ============================================ WARNING: possible recursive locking detected 6.8.0-rc3-syzkaller-00047-ged5551279c91 #0 Not tainted -------------------------------------------- kworker/0:2/694 is trying to acquire lock: ffff888109f20b70 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: vb2_video_unregister_device drivers/media/common/videobuf2/videobuf2-v4l2.c:1269 [inline] ffff888109f20b70 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: vb2_video_unregister_device+0x12b/0x2d0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1245 but task is already holding lock: ffff888109f20b70 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: usbtv_video_free+0x28/0x70 drivers/media/usb/usbtv/usbtv-video.c:966 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&usbtv->vb2q_lock); lock(&usbtv->vb2q_lock); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by kworker/0:2/694: #0: ffff888106ad2138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x789/0x15d0 kernel/workqueue.c:2608 #1: ffffc90001c0fd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7eb/0x15d0 kernel/workqueue.c:2609 #2: ffff88810af2f190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline] #2: ffff88810af2f190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f40 drivers/usb/core/hub.c:5840 #3: ffff888107799190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline] #3: ffff888107799190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x10a/0x910 drivers/usb/core/hub.c:2287 #4: ffff88810779a160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline] #4: ffff88810779a160 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1095 [inline] #4: ffff88810779a160 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa4/0x610 drivers/base/dd.c:1292 #5: ffff888109f20b70 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: usbtv_video_free+0x28/0x70 drivers/media/usb/usbtv/usbtv-video.c:966 #6: ffff888109f20ae0 (&usbtv->v4l2_lock){+.+.}-{3:3}, at: usbtv_video_free+0x32/0x70 drivers/media/usb/usbtv/usbtv-video.c:967 stack backtrace: CPU: 0 PID: 694 Comm: kworker/0:2 Not tainted 6.8.0-rc3-syzkaller-00047-ged5551279c91 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Workqueue: usb_hub_wq hub_event Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x210a/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:752 vb2_video_unregister_device drivers/media/common/videobuf2/videobuf2-v4l2.c:1269 [inline] vb2_video_unregister_device+0x12b/0x2d0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1245 usbtv_video_free+0x4a/0x70 drivers/media/usb/usbtv/usbtv-video.c:970 usbtv_disconnect+0x5c/0xd0 drivers/media/usb/usbtv/usbtv-core.c:138 usb_unbind_interface+0x1e5/0x960 drivers/usb/core/driver.c:461 device_remove drivers/base/dd.c:569 [inline] device_remove+0x11f/0x170 drivers/base/dd.c:561 __device_release_driver drivers/base/dd.c:1272 [inline] device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1295 bus_remove_device+0x22c/0x420 drivers/base/bus.c:574 device_del+0x39a/0xa50 drivers/base/core.c:3814 usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1416 usb_disconnect+0x2e1/0x910 drivers/usb/core/hub.c:2296 hub_port_connect drivers/usb/core/hub.c:5352 [inline] hub_port_connect_change drivers/usb/core/hub.c:5652 [inline] port_event drivers/usb/core/hub.c:5812 [inline] hub_event+0x1be0/0x4f40 drivers/usb/core/hub.c:5894 process_one_work+0x886/0x15d0 kernel/workqueue.c:2633 process_scheduled_works kernel/workqueue.c:2706 [inline] worker_thread+0x8b9/0x1290 kernel/workqueue.c:2787 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
