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[Bug c/69624] sanitize-coverage=trace-pc miscompiles kernel
- From: "dvyukov at google dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 02 Feb 2016 14:49:29 +0000
- Subject: [Bug c/69624] sanitize-coverage=trace-pc miscompiles kernel
- Auto-submitted: auto-generated
- References: <bug-69624-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69624
--- Comment #8 from Dmitry Vyukov <dvyukov at google dot com> ---
First of all, are you sure that r12 is not 0 before the call?
Deference of 0xdffffc0000000000 is how KASAN reacts on NULL deref, it does
shadow check before the memory accesses. If original address is NULL, the
shadow check will go to 0xdffffc0000000000. I see such GPFs quite frequently,
so that's what I would assume first.
If you just switched to gcc6, then it can be some latent bug (undefined
behavior), which started to fire with a new compiler.
p.s. I can reproduce the generated code now.