Hello,
syzbot found the following issue on:
HEAD commit: b09c3451 Linux 4.19.149
git tree: linux-4.19.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=1499703f900000
kernel config:
https://syzkaller.appspot.com/x/.config?x=d7c6dfb55644e8fd
dashboard link:
https://syzkaller.appspot.com/bug?extid=66f92fe4a74ddcc863bc
compiler: gcc (GCC) 10.1.0-syz 20200507
Unfortunately, I don't have any reproducer for this issue yet.
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+66f92f...@syzkaller.appspotmail.com
vhci_hcd vhci_hcd.0: pdev(4) rhport(4) sockfd(13)
vhci_hcd vhci_hcd.0: devid(0) speed(3) speed_str(high-speed)
vhci_hcd: connection closed
==================================================================
vhci_hcd: vhci_device speed not set
BUG: KASAN: null-ptr-deref in atomic_inc include/asm-generic/atomic-instrumented.h:109 [inline]
BUG: KASAN: null-ptr-deref in kthread_stop+0x72/0x6f0 kernel/kthread.c:558
Write of size 4 at addr 000000000000001c by task kworker/u4:2/47
vhci_hcd: Failed attach request for unsupported USB speed: UNKNOWN
CPU: 1 PID: 47 Comm: kworker/u4:2 Not tainted 4.19.149-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usbip_event event_handler
Call Trace:
vhci_hcd vhci_hcd.0: pdev(0) rhport(0) sockfd(3)
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x22c/0x33e lib/dump_stack.c:118
vhci_hcd vhci_hcd.0: devid(0) speed(1) speed_str(low-speed)
kasan_report_error.cold+0xa7/0xb9 mm/kasan/report.c:352
vhci_hcd: connection closed
kasan_report+0x8f/0x96 mm/kasan/report.c:412
vhci_hcd: connection closed
vhci_hcd vhci_hcd.0: port 0 already used
atomic_inc include/asm-generic/atomic-instrumented.h:109 [inline]
kthread_stop+0x72/0x6f0 kernel/kthread.c:558
vhci_shutdown_connection+0x13f/0x230 drivers/usb/usbip/vhci_hcd.c:1021
event_handler+0x1a5/0x450 drivers/usb/usbip/usbip_event.c:78
process_one_work+0x796/0x14e0 kernel/workqueue.c:2155
worker_thread+0x64c/0x1130 kernel/workqueue.c:2298
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
==================================================================
vhci_hcd: connection closed
usb 17-4: new full-speed USB device number 3 using vhci_hcd
---
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