This is a note to let you know that I've just added the patch titled usbip: synchronize event handler with sysfs code paths to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usbip-synchronize-event-handler-with-sysfs-code-paths.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 363eaa3a450abb4e63bd6e3ad79d1f7a0f717814 Mon Sep 17 00:00:00 2001 From: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> Date: Mon, 29 Mar 2021 19:36:51 -0600 Subject: usbip: synchronize event handler with sysfs code paths From: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx Reported-and-tested-by: syzbot+a93fba6d384346a761e3@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@xxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/usbip/usbip_event.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/usb/usbip/usbip_event.c +++ b/drivers/usb/usbip/usbip_event.c @@ -84,6 +84,7 @@ static void event_handler(struct work_st 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_st ud->eh_ops.unusable(ud); unset_event(ud, USBIP_EH_UNUSABLE); } + mutex_unlock(&ud->sysfs_lock); wake_up(&ud->eh_waitq); } Patches currently in stable-queue which might be from skhan@xxxxxxxxxxxxxxxxxxx are queue-4.14/usbip-synchronize-event-handler-with-sysfs-code-paths.patch queue-4.14/usbip-add-sysfs_lock-to-synchronize-sysfs-code-paths.patch queue-4.14/usbip-stub-dev-synchronize-sysfs-code-paths.patch