syzbot reports an error on flush_request_modules() for the second device. This workqueue was never initialised so simply remove the offending line. usb 1-1: USB disconnect, device number 2 em28xx 1-1:1.153: Disconnecting em28xx #1 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3031 __flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ #25 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xca/0x13e lib/dump_stack.c:113 panic+0x2a3/0x6da kernel/panic.c:219 __warn.cold+0x20/0x4a kernel/panic.c:576 report_bug+0x262/0x2a0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:179 [inline] fixup_bug arch/x86/kernel/traps.c:174 [inline] do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272 do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026 RIP: 0010:__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031 Code: 9a 22 00 48 c7 c7 20 e4 c5 85 e8 d9 3a 0d 00 0f 0b 45 31 e4 e9 98 86 ff ff e8 51 9a 22 00 48 c7 c7 20 e4 c5 85 e8 be 3a 0d 00 <0f> 0b 45 31 e4 e9 7d 86 ff ff e8 36 9a 22 00 48 c7 c7 20 e4 c5 85 RSP: 0018:ffff8881da20f720 EFLAGS: 00010286 RAX: 0000000000000024 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed103b441ed6 RBP: ffff8881da20f888 R08: 0000000000000024 R09: fffffbfff11acd9a R10: fffffbfff11acd99 R11: ffffffff88d66ccf R12: 0000000000000000 R13: 0000000000000001 R14: ffff8881c6685df8 R15: ffff8881d2a85b78 flush_request_modules drivers/media/usb/em28xx/em28xx-cards.c:3325 [inline] em28xx_usb_disconnect.cold+0x280/0x2a6 drivers/media/usb/em28xx/em28xx-cards.c:4023 usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423 __device_release_driver drivers/base/dd.c:1120 [inline] device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151 bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556 device_del+0x420/0xb10 drivers/base/core.c:2288 usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237 usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199 hub_port_connect drivers/usb/core/hub.c:4949 [inline] hub_port_connect_change drivers/usb/core/hub.c:5213 [inline] port_event drivers/usb/core/hub.c:5359 [inline] hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269 process_scheduled_works kernel/workqueue.c:2331 [inline] worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Kernel Offset: disabled Rebooting in 86400 seconds.. Reported-by: syzbot+b7f57261c521087d89bb@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Sean Young <sean@xxxxxxxx> --- drivers/media/usb/em28xx/em28xx-cards.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c index 6e33782c3ca6..5983e72a0622 100644 --- a/drivers/media/usb/em28xx/em28xx-cards.c +++ b/drivers/media/usb/em28xx/em28xx-cards.c @@ -4019,7 +4019,6 @@ static void em28xx_usb_disconnect(struct usb_interface *intf) dev->dev_next->disconnected = 1; dev_info(&dev->intf->dev, "Disconnecting %s\n", dev->dev_next->name); - flush_request_modules(dev->dev_next); } dev->disconnected = 1; -- 2.21.0
