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 4.9-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-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Apr 20 01:51:40 PM CEST 2021
From: Tom Seewald <tseewald@xxxxxxxxx>
Date: Fri, 16 Apr 2021 15:53:19 -0500
Subject: usbip: synchronize event handler with sysfs code paths
To: stable@xxxxxxxxxxxxxxx
Cc: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>, syzbot+a93fba6d384346a761e3@xxxxxxxxxxxxxxxxxxxxxxxxx, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Tom Seewald <tseewald@xxxxxxxxx>, Valentina Manea <valentina.manea.m@xxxxxxxxx>, Shuah Khan <shuah@xxxxxxxxxx>
Message-ID: <20210416205319.14075-4-tseewald@xxxxxxxxx>
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 # 4.9.x
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: Tom Seewald <tseewald@xxxxxxxxx>
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 tseewald@xxxxxxxxx are
queue-4.9/usbip-vudc-synchronize-sysfs-code-paths.patch
queue-4.9/usbip-fix-incorrect-double-assignment-to-udc-ud.tcp_rx.patch
queue-4.9/usbip-synchronize-event-handler-with-sysfs-code-paths.patch
queue-4.9/usbip-add-sysfs_lock-to-synchronize-sysfs-code-paths.patch
queue-4.9/usbip-stub-dev-synchronize-sysfs-code-paths.patch
