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usbip: synchronize event handler with sysfs code paths

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commit 363eaa3a450abb4e63bd6e3ad79d1f7a0f717814 upstream.

Fuzzing uncovered race condition between sysfs code paths in usbip
drivers. Device connect/disconnect code paths initiated through
sysfs interface are prone to races if disconnect happens during
connect and vice versa.

Use sysfs_lock to synchronize event handler with sysfs paths
in usbip drivers.

Cc: stable@vger.kernel.org # 4.9.x
Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@linuxfoundation.org
Signed-off-by: Tom Seewald <tseewald@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shuah Khan 2021-04-16 15:53:19 -05:00 committed by Greg Kroah-Hartman
parent 94b9c4c583
commit 0cc3218310
1 changed files with 2 additions and 0 deletions
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2
drivers/usb/usbip/usbip_event.c
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@ -84,6 +84,7 @@ static void event_handler(struct work_struct *work)
while ((ud = get_event()) != NULL) {
usbip_dbg_eh("pending event %lx\n", ud->event);
mutex_lock(&ud->sysfs_lock);
/*
* NOTE: shutdown must come first.
* Shutdown the device.
@ -104,6 +105,7 @@ static void event_handler(struct work_struct *work)
ud->eh_ops.unusable(ud);
unset_event(ud, USBIP_EH_UNUSABLE);
}
mutex_unlock(&ud->sysfs_lock);
wake_up(&ud->eh_waitq);
}