Re: [Linux-ia64] SIGILL errors in strncpu (NAT consumption)

["Hideki Yamamoto" <hideki@hpc.bs1.fc.nec.co.jp>]

 Hi there,

 I have a favor to ask David.
 If possible, plase give me the patch you had resolved
 this problem. I have been looking for the patch in all
 email(linux-ia64) but I could not find this patch.

 Thanks.

> David Mosberger took a look at the strncpy code & spotted
> the error:
> 
> From David:
> >> I took a closer look and there seem to be several bugs in the routine:
> >> 
> >>  (1) I don't think it's save to do:
> >> 
> >>                 chk.s r[MEMLAT], .recovery3
> >>                 mov value = r[MEMLAT]
> >> 
> >>      in the same cycle.  In the patch below, I fixed this by adding a
> >>      stop bit, but obviously it would be better to avoid that (either
> >>      by re-ordering the code or by adding a pipeline stage).
> >> 
> >>  (2) stop bit was missing after br.cloop.dptk
> >> 
> >>  (3) off-by-one error in .recovery4 code: the destination should be
> >>      r[MEMLAT-1], not r[MEMLAT]
> >> 
> >>  (4) I believe the address calcuation in .recovery3 and .recovery4 may
> >>      also be off by 8; this is just based on eye-balling the code though,
> >>      so I may be wrong
> >> 
> >> Hope this helps,
> >> 
> >>         --david
> >> 
> 
> 
> ---- 
> Test case - run ~12 copies of this in parallel.
> 
> #include <stdio.h>
> #include <signal.h>
> #include <string.h>
> #include <time.h>
> 
> char *dest, *src;
> 
> void
> sigill_handler(int sig)
> {
>         fprintf(stderr,"SIGILL: pid %d, dest 0x%lx, src 0x%lx\n",
>                 getpid(), (long)dest, (long)src);
>         exit(1);
> }
> 
> int
> main() {
>   time_t temp1;
>   char *p, buffer[1024];
> 
>   signal(SIGILL, sigill_handler);
>   
>   time(&temp1);
>   src = ctime(&temp1);
> 
>   dest = buffer;
> 
>   printf("%d\n", strlen(src));
> 
>   while(1)
>       strncpy(buffer,src,strlen(src));
> }
> 
> 
> -- 
> Thanks
> 
> Jack Steiner    (651-683-5302)   (vnet 233-5302)      steiner@sgi.com
> 
> 
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