* Division Bugs
@ 2015-04-04 20:49 Michael Zimmermann
2015-04-06 16:34 ` Andrei Borzenkov
0 siblings, 1 reply; 2+ messages in thread
From: Michael Zimmermann @ 2015-04-04 20:49 UTC (permalink / raw)
To: The development of GNU GRUB
I think I found a bug but I'm not sure.
http://git.savannah.gnu.org/gitweb/?p=grub.git;a=blob;f=grub-core/lib/division.c;h=920a79f18b7a7180bc5bcf18987c043b1df56687;hb=refs/heads/master#l53
at line 53 u write a value to ro:
*ro = r;
now take a look at the callers:
http://git.savannah.gnu.org/gitweb/?p=grub.git;a=blob;f=grub-core/kern/compiler-rt.c;h=d4cc15513aabea3061bd2dddc896b105bb180a5b;hb=refs/heads/master
some look like this which should be ok:
grub_divmod64s (a, b, &ret);
but there are others like this:
grub_divmod64s (a, b, 0);
I got a "data abort, translation fault on write" exception after
compiling a lib which uses that division function.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Division Bugs
2015-04-04 20:49 Division Bugs Michael Zimmermann
@ 2015-04-06 16:34 ` Andrei Borzenkov
0 siblings, 0 replies; 2+ messages in thread
From: Andrei Borzenkov @ 2015-04-06 16:34 UTC (permalink / raw)
To: Michael Zimmermann; +Cc: The development of GNU GRUB
В Sat, 4 Apr 2015 22:49:28 +0200
Michael Zimmermann <sigmaepsilon92@gmail.com> пишет:
> I think I found a bug but I'm not sure.
>
> http://git.savannah.gnu.org/gitweb/?p=grub.git;a=blob;f=grub-core/lib/division.c;h=920a79f18b7a7180bc5bcf18987c043b1df56687;hb=refs/heads/master#l53
> at line 53 u write a value to ro:
> *ro = r;
>
> now take a look at the callers:
> http://git.savannah.gnu.org/gitweb/?p=grub.git;a=blob;f=grub-core/kern/compiler-rt.c;h=d4cc15513aabea3061bd2dddc896b105bb180a5b;hb=refs/heads/master
>
> some look like this which should be ok:
> grub_divmod64s (a, b, &ret);
>
> but there are others like this:
> grub_divmod64s (a, b, 0);
>
> I got a "data abort, translation fault on write" exception after
> compiling a lib which uses that division function.
>
Fixed. Unfortunately there does not appear any easy way to
regression test it. Dereferencing 0x0 pointer does not trigger an error,
unless you setup address mapping appropriately.
Thank you for report!
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2015-04-06 16:34 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-04-04 20:49 Division Bugs Michael Zimmermann
2015-04-06 16:34 ` Andrei Borzenkov
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.