Linux-USB Archive on lore.kernel.org
 help / color / Atom feed
From: Shuah Khan <skhan@linuxfoundation.org>
To: valentina.manea.m@gmail.com, shuah@kernel.org,
	gregkh@linuxfoundation.org
Cc: Shuah Khan <skhan@linuxfoundation.org>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com,
	stable@vger.kernel.org
Subject: [PATCH 4/4] usbip: synchronize event handler with sysfs code paths
Date: Mon, 29 Mar 2021 19:36:51 -0600
Message-ID: <c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@linuxfoundation.org> (raw)
In-Reply-To: <cover.1616807117.git.skhan@linuxfoundation.org>

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(+)

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);
 	}
-- 
2.27.0


      parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-30  1:36 [PATCH 0/4] usbip synchronize " Shuah Khan
2021-03-30  1:36 ` [PATCH 1/4] usbip: add sysfs_lock to " Shuah Khan
2021-03-30  1:36 ` [PATCH 2/4] usbip: stub-dev " Shuah Khan
2021-03-30  1:36 ` [PATCH 3/4] usbip: vudc " Shuah Khan
2021-03-30  1:36 ` Shuah Khan [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@linuxfoundation.org \
    --to=skhan@linuxfoundation.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=shuah@kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com \
    --cc=valentina.manea.m@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-USB Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-usb/0 linux-usb/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-usb linux-usb/ https://lore.kernel.org/linux-usb \
		linux-usb@vger.kernel.org
	public-inbox-index linux-usb

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-usb


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git