Date: Fri, 9 Mar 2007 09:28:28 GMT From: Maurice Castro<maurice@castro.aus.net> To: freebsd-gnats-submit@FreeBSD.org Subject: usb/110122: usb_interrupt_read does not respect timeout Message-ID: <200703090928.l299SSgR077668@www.freebsd.org> Resent-Message-ID: <200703090930.l299U3f7089232@freefall.freebsd.org>
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>Number: 110122
>Category: usb
>Synopsis: usb_interrupt_read does not respect timeout
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-usb
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Mar 09 09:30:03 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator: Maurice Castro
>Release: 6.2-Release etc
>Organization:
Clarinet Internet Solutions
>Environment:
FreeBSD mud.clari.net.au 6.2-RC1 FreeBSD 6.2-RC1 #2: Tue Mar 6 09:56:42 EST 2007 root@mud.clari.net.au:/usr/src/sys/i386/compile/USB i386
>Description:
usb_interrupt_read does not respect timeouts. This is necessary for the correct operation of libusb. The attached patch returns a zero length read after a timeout. This is consistent with the behaviour expected by libusb.
This PR replaces to broken reports:
usb/109959
usb/110031
The problem exists in all versions of FreeBSD up to 6.2 and possibly NetBSD and OpenBSD.
>How-To-Repeat:
The problem is easily reproduced. The bcmxcp_usb driver freezes on initialisation without the patch as the call to usb_interrupt_read never returns.
>Fix:
The patch applies src/sys/dev/usb/ugen.c
Patch attached with submission follows:
--- ugen.c.orig Tue Mar 6 13:36:15 2007
+++ ugen.c Tue Mar 6 09:56:20 2007
@@ -740,11 +740,17 @@
}
sce->state |= UGEN_ASLP;
DPRINTFN(5, ("ugenread: sleep on %p\n", sce));
- error = tsleep(sce, PZERO | PCATCH, "ugenri", 0);
+ error = tsleep(sce, PZERO | PCATCH, "ugenri", sce->timeout);
sce->state &= ~UGEN_ASLP;
DPRINTFN(5, ("ugenread: woke, error=%d\n", error));
if (sc->sc_dying)
error = EIO;
+ /* we timed out - return 0 bytes */
+ if (error == EAGAIN)
+ {
+ error = 0;
+ break;
+ }
if (error)
break;
}
>Release-Note:
>Audit-Trail:
>Unformatted:
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