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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/108552] Linux i386 kernel 5.14 memory
 corruption for pre_compound_page() when gcov is enabled
Date: Fri, 27 Jan 2023 15:18:56 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108552

--- Comment #28 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #27)
> (In reply to Richard Biener from comment #25)
> > Ah, reading more comments, no - it probably doesn't.  Jakub correctly s=
ays
> > that there seems to be a data race necessary to trigger this, so it doe=
sn't
> > seem to be a GCC issue?
>=20
> Well, we could in -fprofile-update=3Dsingle (or perhaps in a new single-l=
ike
> mode) mark the gcov artificial vars volatile or with some flag that would=
 at
> least cause reload not to reread values from memory.  The profiling would=
 be
> still racy, but at the expense of somewhat slower code (with volatile mor=
e,
> with special flag less so) slightly less so (as it would e.g. prevent the
> compiler from avoiding the rereads).

-fprofile-update=3Dvolatile?  Huh, sure, we could do that.=