From 5105c1c0cab6679c46ec1a52edae95046ad04140 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Wed, 21 Apr 2021 11:32:43 +0000 Subject: [PATCH] usbip: synchronize event handler with sysfs code paths MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit stable inclusion from stable-5.10.30 commit f06cb4641b15e55c2c7d47c44a57a8c9208b92ef bugzilla: 51791 -------------------------------- 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 Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Signed-off-by: Shuah Khan Link: https://lore.kernel.org/r/c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Chen Jun Acked-by:  Weilong Chen Signed-off-by: Zheng Zengkai --- drivers/usb/usbip/usbip_event.c | 2 ++ 1 file changed, 2 insertions(+) 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) ud->eh_ops.unusable(ud); unset_event(ud, USBIP_EH_UNUSABLE); } + mutex_unlock(&ud->sysfs_lock); wake_up(&ud->eh_waitq); } -- GitLab