[moderation] [usb?] KCSAN: data-race in mon_reader_del / usb_hcd_submit_urb (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: efb44d93a620 Merge tag 'x86-urgent-2026-09-27' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12e74ac9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ea1e6d8de13bab08
dashboard link: https://syzkaller.appspot.com/bug?extid=21298827560ae41e73b5
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
CC: [gre...@linuxfoundation.org linux-...@vger.kernel.org linu...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3ef66b98f7be/disk-efb44d93.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c2aea5641580/vmlinux-efb44d93.xz
kernel image: https://storage.googleapis.com/syzbot-assets/485eed251dec/bzImage-efb44d93.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+212988...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in mon_reader_del / usb_hcd_submit_urb

write to 0xffff8881039c5080 of 4 bytes by task 6488 on cpu 0:
mon_stop drivers/usb/mon/mon_main.c:166 [inline]
mon_reader_del+0x1ca/0x260 drivers/usb/mon/mon_main.c:73
mon_bin_release+0x67/0x120 drivers/usb/mon/mon_bin.c:795
__fput+0x29e/0x630 fs/file_table.c:512
____fput+0x1c/0x30 fs/file_table.c:540
task_work_run+0x130/0x1a0 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1e4/0x8c0 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x212/0x360 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881039c5080 of 4 bytes by task 37 on cpu 1:
usbmon_urb_submit include/linux/usb/hcd.h:723 [inline]
usb_hcd_submit_urb+0x64/0x11f0 drivers/usb/core/hcd.c:1527
usb_submit_urb+0xaa3/0xbb0 drivers/usb/core/urb.c:586
usb_start_wait_urb+0x91/0x220 drivers/usb/core/message.c:62
usb_internal_control_msg drivers/usb/core/message.c:117 [inline]
usb_control_msg+0x182/0x240 drivers/usb/core/message.c:167
get_port_status drivers/usb/core/hub.c:607 [inline]
hub_ext_port_status+0xb4/0x410 drivers/usb/core/hub.c:624
usb_hub_port_status drivers/usb/core/hub.c:674 [inline]
port_event drivers/usb/core/hub.c:5774 [inline]
hub_event+0x47e/0x2aa0 drivers/usb/core/hub.c:5966
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3479
worker_thread+0x569/0x750 kernel/workqueue.c:3560
kthread+0x223/0x270 kernel/kthread.c:436
ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 37 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: usb_hub_wq hub_event
==================================================================


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