NetBSD Problem Report #41094

From www@NetBSD.org  Sun Mar 29 16:12:18 2009
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Date: Sun, 29 Mar 2009 16:12:17 +0000 (UTC)
From: matteo@beccati.com
Reply-To: matteo@beccati.com
To: gnats-bugs@NetBSD.org
Subject: sigtimedwait returns EAGAIN instead of EINVAL if timeout is invalid
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>Number:         41094
>Category:       kern
>Synopsis:       sigtimedwait returns EAGAIN instead of EINVAL if timeout is invalid
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Mar 29 16:15:00 +0000 2009
>Closed-Date:    Mon May 18 06:35:02 +0000 2009
>Last-Modified:  Mon May 18 06:35:02 +0000 2009
>Originator:     Matteo Beccati
>Release:        NetBSD 5.0_RC3
>Organization:
>Environment:
NetBSD epia.hq.beccati.com 5.0_RC3 NetBSD 5.0_RC3 (EPIA) #5: Sun Mar 29 17:17:36 CEST 2009  root@aperol.beccati.com:/array1/compile/netbsd-5/src/sys/arch/i386/compile/obj/EPIA i386
>Description:
sigtimedwait returns EAGAIN instead of EINVAL if the specified timeout overflows when converted in Hz.

From the man page:

     sigtimedwait() may also fail if:

     [EINVAL]           The specified timeout was invalid.

>How-To-Repeat:
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <limits.h>
#include <time.h>
#include <errno.h>

int main(int argc, char **argv)
{
        sigset_t mask;
        siginfo_t info;
        struct timespec ts;

        sigemptyset(&mask);
        sigaddset(&mask, SIGTERM);

        sigprocmask(SIG_BLOCK, &mask, NULL);

        ts.tv_sec = LONG_MAX;
        ts.tv_nsec = 999;

        int ret = sigtimedwait(&mask, &info, &ts);

        printf("Ret: %d, Error: %d %s\n", ret, errno, strerror(errno));

        return 0;
}

>Fix:
Index: sys/kern/sys_sig.c
===================================================================
RCS file: /cvsroot/src/sys/kern/sys_sig.c,v
retrieving revision 1.17
diff -u -r1.17 sys_sig.c
--- sys/kern/sys_sig.c  15 Oct 2008 06:51:20 -0000      1.17
+++ sys/kern/sys_sig.c  29 Mar 2009 16:10:53 -0000
@@ -640,7 +640,7 @@
                if (timo == 0 && ts.tv_sec == 0 && ts.tv_nsec > 0)
                        timo = 1;
                if (timo <= 0)
-                       return (EAGAIN);
+                       return (EINVAL);

                /*
                 * Remember current uptime, it would be used in

>Release-Note:

>Audit-Trail:
From: Matteo Beccati <matteo@beccati.com>
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: kern/41094: sigtimedwait returns EAGAIN instead of EINVAL if
 timeout is invalid
Date: Sun, 29 Mar 2009 18:29:08 +0200

 However, the fix doesn't work if both tv_sec and tv_usec == LONG_MAX.

 Reusing the mstohz definition from sys/sys/param.h, with hz set to 100, 
 I got: 2147483649147ms -> 100hz


From: christos@zoulas.com (Christos Zoulas)
To: gnats-bugs@NetBSD.org, kern-bug-people@netbsd.org, 
	gnats-admin@netbsd.org, netbsd-bugs@netbsd.org, matteo@beccati.com
Cc: 
Subject: Re: kern/41094: sigtimedwait returns EAGAIN instead of EINVAL if timeout is invalid
Date: Sun, 29 Mar 2009 12:36:45 -0400

 On Mar 29,  4:30pm, matteo@beccati.com (Matteo Beccati) wrote:
 -- Subject: Re: kern/41094: sigtimedwait returns EAGAIN instead of EINVAL if 

 | The following reply was made to PR kern/41094; it has been noted by GNATS.
 | 
 | From: Matteo Beccati <matteo@beccati.com>
 | To: gnats-bugs@NetBSD.org
 | Cc: 
 | Subject: Re: kern/41094: sigtimedwait returns EAGAIN instead of EINVAL if
 |  timeout is invalid
 | Date: Sun, 29 Mar 2009 18:29:08 +0200
 | 
 |  However, the fix doesn't work if both tv_sec and tv_usec == LONG_MAX.
 |  
 |  Reusing the mstohz definition from sys/sys/param.h, with hz set to 100, 
 |  I got: 2147483649147ms -> 100hz

 Does changing the mstohz(ms) to tstohz(&ts) work?

 christos

From: Matteo Beccati <matteo@beccati.com>
To: gnats-bugs@NetBSD.org
Cc: kern-bug-people@netbsd.org, gnats-admin@netbsd.org, 
 netbsd-bugs@netbsd.org
Subject: Re: kern/41094: sigtimedwait returns EAGAIN instead of EINVAL if
 timeout is invalid
Date: Sun, 29 Mar 2009 19:07:05 +0200

 Christos Zoulas wrote:
 >  |  However, the fix doesn't work if both tv_sec and tv_usec == LONG_MAX.
 >  |  
 >  |  Reusing the mstohz definition from sys/sys/param.h, with hz set to 100, 
 >  |  I got: 2147483649147ms -> 100hz
 >  
 >  Does changing the mstohz(ms) to tstohz(&ts) work?

 Updated the kernel, the function now waits indefinitely. Probably the 
 timeout was rounded down to INT_MAX, but I can't tell as it's in the kernel.

 For reference, looks like Linux performs some additional validation on 
 the usec field:

 sec = LONG_MAX, usec = 0: ok
 sec = LONG_MAX, usec = 999999999: ok
 sec = 0, usec = 1000000000: EINVAL
 sec = LONG_MAX, usec = LONG_MAX: EINVAL

From: Matteo Beccati <matteo@beccati.com>
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: kern/41094: sigtimedwait returns EAGAIN instead of EINVAL if
 timeout is invalid
Date: Wed, 01 Apr 2009 11:30:33 +0200

 Thanks for the fix in -current. I've applied it to netbsd-5 and works good.

 Can I request a pullup of the related changes to the netbsd-5 branch:

 cvs rdiff -r 1.21 -r 1.23 src/sys/kern/sys_sig.c


 Thanks

State-Changed-From-To: open->feedback
State-Changed-By: rmind@NetBSD.org
State-Changed-When: Wed, 01 Apr 2009 10:46:53 +0000
State-Changed-Why:
Christos fixed the return value.  Request for pull-up sent.
Thanks for good bug-report.

Are other checks required by POSIX?


From: Matteo Beccati <matteo@beccati.com>
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: kern/41094 (sigtimedwait returns EAGAIN instead of EINVAL if
 timeout is invalid)
Date: Tue, 05 May 2009 11:08:42 +0200

 rmind@NetBSD.org wrote:
 > Are other checks required by POSIX?

 I'm not a POSIX expert, but I haven't noticed anything else during my tests.

 Sorry for the late feedback: I thought I responsed while in fact I did not.


 Cheers

State-Changed-From-To: feedback->closed
State-Changed-By: dholland@NetBSD.org
State-Changed-When: Mon, 18 May 2009 06:35:02 +0000
State-Changed-Why:
Fixed & pullups done. Thanks.


>Unformatted:

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