Linux CAN drivers development
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From: Jimmy Assarsson <jimmyassarsson@gmail.com>
To: linux-can@vger.kernel.org
Cc: Jimmy Assarsson <jimmyassarsson@gmail.com>
Subject: [PATCH 2/3] can: kvaser_usb: Fix comparison bug in kvaser_usb_read_bulk_callback()
Date: Tue, 21 Nov 2017 08:22:27 +0100	[thread overview]
Message-ID: <20171121072228.7570-3-jimmyassarsson@gmail.com> (raw)
In-Reply-To: <20171121072228.7570-1-jimmyassarsson@gmail.com>

The conditon in the while-loop becomes true when actual_length is less than
2 (MSG_HEADER_LEN). In best case we end up with a former, already
dispatched msg, that got msg->len greater than actual_length. This will
result in a "Format error" error printout.

Problem seen when unplugging a Kvaser USB device connected to a vbox guest.

warning: comparison between signed and unsigned integer expressions
[-Wsign-compare]

Signed-off-by: Jimmy Assarsson <jimmyassarsson@gmail.com>
---
 drivers/net/can/usb/kvaser_usb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c
index 075644591498..d87e330a20b3 100644
--- a/drivers/net/can/usb/kvaser_usb.c
+++ b/drivers/net/can/usb/kvaser_usb.c
@@ -1334,7 +1334,7 @@ static void kvaser_usb_read_bulk_callback(struct urb *urb)
 		goto resubmit_urb;
 	}
 
-	while (pos <= urb->actual_length - MSG_HEADER_LEN) {
+	while (pos <= (int)(urb->actual_length - MSG_HEADER_LEN)) {
 		msg = urb->transfer_buffer + pos;
 
 		/* The Kvaser firmware can only read and write messages that
-- 
2.15.0


  parent reply	other threads:[~2017-11-21  7:22 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-21  7:22 [PATCH 0/3] Fixes for kvaser_usb driver Jimmy Assarsson
2017-11-21  7:22 ` [PATCH 1/3] can: kvaser_usb: free buf in error paths Jimmy Assarsson
2017-11-21  7:22 ` Jimmy Assarsson [this message]
2017-11-21  7:22 ` [PATCH 3/3] can: kvaser_usb: ratelimit errors if incomplete messages are received Jimmy Assarsson
2017-11-21 13:14 ` [PATCH 0/3] Fixes for kvaser_usb driver Marc Kleine-Budde

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