Re: [PATCH] prevent timespec/timeval to ktime_t overflow

[Andrew Morton <akpm@osdl.org>]

On Fri, 01 Sep 2006 10:56:19 +0200
Thomas Gleixner <tglx@linutronix.de> wrote:

> On Thu, 2006-08-31 at 20:46 -0700, Andrew Morton wrote:
> > >   * ktime_t definitions when using the 64-bit scalar representation:
> > > @@ -73,6 +74,10 @@ typedef union {
> > >   */
> > >  static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
> > >  {
> > > +#if (BITS_PER_LONG == 64)
> > > +	if (unlikely(secs >= KTIME_SEC_MAX))
> > > +		return (ktime_t){ .tv64 = KTIME_MAX };
> > > +#endif
> > >  	return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs };
> > >  }
> > >  
> > 
> > This makes my FC3 x86_64 testbox hang during udev startup.  sysrq-T trace at
> > http://www.zip.com.au/~akpm/linux/patches/stuff/log-x.
> 
> Does not help much.
> 
> > I had a quick look at the args to hrtimer_nanosleep and all seems to be in
> > order.
> 
> Hmm. I can not reproduce that on any one of my boxen. Can you please try
> with this debug variant, so we have a chance to figure out what's wrong.
> 

With that patch the machine emits 88 bigabytes of stuff then locks up. 
Something a little less aggressive is needed, methinks.