KCSAN: data-race in usbdev_ioctl / usbdev_ioctl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: bf3e7628 Merge branch 'mtd/fixes' of git://git.kernel.org/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14881f32500000
kernel config: https://syzkaller.appspot.com/x/.config?x=76dfc991796328d4
dashboard link: https://syzkaller.appspot.com/bug?extid=1bf0401628b822323084
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [gre...@linuxfoundation.org jeremy...@arm.com linux-...@vger.kernel.org linu...@vger.kernel.org st...@rowland.harvard.edu vi...@zeniv.linux.org.uk]

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+1bf040...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in usbdev_ioctl / usbdev_ioctl

write to 0xffff8881039466f0 of 8 bytes by task 30126 on cpu 0:
usbdev_do_ioctl drivers/usb/core/devio.c:2699 [inline]
usbdev_ioctl+0x62e/0x3970 drivers/usb/core/devio.c:2708
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
__x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8881039466f0 of 8 bytes by task 30121 on cpu 1:
usbdev_do_ioctl drivers/usb/core/devio.c:2699 [inline]
usbdev_ioctl+0x62e/0x3970 drivers/usb/core/devio.c:2708
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
__x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 30121 Comm: syz-executor.0 Not tainted 5.10.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 30121 Comm: syz-executor.0 Not tainted 5.10.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x116/0x15d lib/dump_stack.c:118
panic+0x1e7/0x5fa kernel/panic.c:231
kcsan_report+0x67b/0x680 kernel/kcsan/report.c:634
kcsan_setup_watchpoint+0x46a/0x4d0 kernel/kcsan/core.c:568
usbdev_do_ioctl drivers/usb/core/devio.c:2699 [inline]
usbdev_ioctl+0x62e/0x3970 drivers/usb/core/devio.c:2708
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
__x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45deb9
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb0baa85c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000001b040 RCX: 000000000045deb9
RDX: 0000000020000000 RSI: 00000000c0185500 RDI: 0000000000000003
RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffe15e2b3ef R14: 00007fb0baa869c0 R15: 000000000118bf2c
Kernel Offset: disabled
Rebooting in 86400 seconds..


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.