Commit 363eaa3a authored by Shuah Khan's avatar Shuah Khan Committed by Greg Kroah-Hartman
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usbip: synchronize event handler with sysfs code paths 



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
Reported-and-tested-by: default avatar <syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com>
Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@linuxfoundation.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bd8b8204

drivers/usb/usbip/usbip_event.c

+2 −0
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ 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.
@@ -90,6 +91,7 @@ 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);

	}