From: Thomas Gleixner <tglx@linutronix.de>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: Nathan Lynch <nathanl@linux.ibm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
"linuxppc-dev@ozlabs.org" <linuxppc-dev@ozlabs.org>
Subject: Re: passing NULL to clock_getres (VDSO): terminated by unexpected signal 11
Date: Sun, 20 Oct 2019 17:45:45 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1910201731070.2090@nanos.tec.linutronix.de> (raw)
In-Reply-To: <875zkjipra.fsf@igel.home>
On Sun, 20 Oct 2019, Andreas Schwab wrote:
> On Okt 20 2019, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> > clock_getres(NULL) is hardly valid.
>
> Of course not, it lacks a parameter.
You know exactly what I mean.
> > So special casing
> >
> > clock_getres(clock, NULL);
> >
> > just to make a test case happy is a pointless exercise which does not make
> > any sense at all.
>
> POSIX requires it to work.
POSIX does not mention anything about the validity of the pointer handed to
clock_getres().
https://pubs.opengroup.org/onlinepubs/9699919799/
"The clock_getres(), clock_gettime(), and clock_settime() functions shall fail if:
[EINVAL]
The clock_id argument does not specify a known clock."
EINVAL is the only documented error code for clock_getres().
Again. The VDSO is not a syscall and therefore neither address space
validation of the supplied pointer nor catching an invalid access works
like it does in a syscall.
The only invalid pointer it can catch is NULL, but that's ONE case out of a
gazillion. So what's the value of catching NULL and only NULL?
If you can come up with a solution to handle invalid pointers in the VDSO
gracefully, then I'm surely all ears.
If not then can you please explain why VDSO usage worked without pointer
validation since the time VDSO was invented more than a decade ago and just
now requires full invalid pointer handling?
Thanks,
tglx
next prev parent reply other threads:[~2019-10-20 15:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <0fc22a08-31d9-e4d1-557e-bf5b482a9a20__6444.28012180782$1571503753$gmane$org@c-s.fr>
2019-10-19 19:18 ` passing NULL to clock_getres (VDSO): terminated by unexpected signal 11 Andreas Schwab
2019-10-20 9:20 ` Christophe Leroy
2019-10-20 9:53 ` Andreas Schwab
2019-10-20 10:25 ` Christophe Leroy
2019-10-20 11:44 ` Thomas Gleixner
2019-10-20 12:07 ` Andreas Schwab
2019-10-20 15:45 ` Thomas Gleixner [this message]
2019-10-20 16:08 ` Andreas Schwab
2019-10-20 19:53 ` Thomas Gleixner
2019-10-20 21:17 ` Andreas Schwab
2019-10-21 10:07 ` [PATCH] lib/vdso: Make clock_getres() POSIX compliant again Thomas Gleixner
2019-10-21 15:23 ` Christophe Leroy
2019-10-21 9:03 ` passing NULL to clock_getres (VDSO): terminated by unexpected signal 11 David Laight
2019-10-19 16:46 Christophe Leroy
2019-10-28 15:46 ` Nathan Lynch
2019-10-28 15:50 ` Christophe Leroy
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