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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug sanitizer/111736] Address sanitizer is not compatible with
 named address spaces
Date: Thu, 21 Mar 2024 09:26:33 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111736

--- Comment #20 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Uro=C5=A1 Bizjak from comment #19)
> (In reply to Uro=C5=A1 Bizjak from comment #16)
> > (In reply to Richard Biener from comment #13)
> > > The original testcase is fixed, appearantly slapping 'extern' on the =
int
> > > makes it not effective.
> > >=20
> > > Possibly better amend the
> > >=20
> > >   if (VAR_P (inner) && DECL_HARD_REGISTER (inner))
> > >     return;
> > >=20
> > > check though.  As indicated my fix fixed only VAR_DECL cases, there's
> > > still pointer-based accesses (MEM_REF) to consider.  So possibly even
> > > the following is necessary
> >=20
> > I must admit that to create the patch from Comment #11 I just mindlessly
> > searched for DECL_THREAD_LOCAL_P in asan.cc and amended the location wi=
th
> > ADDR_SPACE_GENERIC_P check.
> >=20
> > However, ASAN should back off from annotating *any* gs: prefixed addres=
s.=20
> >=20
> > I'll test your patch from Comment #13 ASAP.
>=20
> Weee, it works!
>=20
> Decompressing Linux... Parsing ELF... Performing relocations... done.
> Booting the kernel (entry_offset: 0x0000000000000000).
> [    0.000000] Linux version 6.8.0-11485-ge1826833c3a9 (uros@localhost)
> (xgcc (GCC) 14.0.1 20240321 (experimental) [master r14-9588-g415091f0909],
> GNU ld version 2.40-14.fc39) #1 SMP PREEMPT_DYNAMIC Thu Mar 21 09:44:30 C=
ET
> 2024
> ...
>=20
> I have used slightly different patch:
>=20
> --cut here--
> diff --git a/gcc/asan.cc b/gcc/asan.cc
> index cfe83106460..026d079a4a1 100644
> --- a/gcc/asan.cc
> +++ b/gcc/asan.cc
> @@ -2755,6 +2755,9 @@ instrument_derefs (gimple_stmt_iterator *iter, tree=
 t,
>    if (VAR_P (inner) && DECL_HARD_REGISTER (inner))
>      return;
>=20=20
> +  if (!ADDR_SPACE_GENERIC_P (TYPE_ADDR_SPACE (TREE_TYPE (inner))))
> +    return;
> +

Agreed, this looks better.

Though, talking about address spaces, guess we also need to change ubsan.cc,
so that for targetm.addr_space.zero_address_valid (as) case it actually doe=
sn't
try to
verify the pointers aren't NULL (it still should check alignment).=