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[4/4] usbip: synchronize event handler with sysfs code paths

Message ID c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@linuxfoundation.org (mailing list archive)
State Accepted
Commit 363eaa3a450abb4e63bd6e3ad79d1f7a0f717814
Headers show
Series usbip synchronize sysfs code paths | expand

Commit Message

Shuah Khan March 30, 2021, 1:36 a.m. UTC
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.

Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
 drivers/usb/usbip/usbip_event.c | 2 ++
 1 file changed, 2 insertions(+)
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diff --git a/drivers/usb/usbip/usbip_event.c b/drivers/usb/usbip/usbip_event.c
index 5d88917c9631..086ca76dd053 100644
--- a/drivers/usb/usbip/usbip_event.c
+++ b/drivers/usb/usbip/usbip_event.c
@@ -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)
 			unset_event(ud, USBIP_EH_UNUSABLE);
+		mutex_unlock(&ud->sysfs_lock);