From: Peter Zijlstra <peterz@infradead.org>
To: Pengfei Xu <pengfei.xu@intel.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>,
"Yang, Weijiang" <weijiang.yang@intel.com>,
"Su, Heng" <heng.su@intel.com>,
linux-kernel@vger.kernel.org,
Josh Poimboeuf <jpoimboe@redhat.com>,
pbonzini@redhat.com, x86@kernel.org
Subject: Re: [PATCH] x86/kvm, objtool: Avoid fastop ENDBR from being sealed
Date: Thu, 18 Aug 2022 13:06:16 +0200 [thread overview]
Message-ID: <Yv4dKABja9CxqcDS@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <Yv3sha0zujQxW1X8@xpf.sh.intel.com>
On Thu, Aug 18, 2022 at 03:38:45PM +0800, Pengfei Xu wrote:
> And this "Missing ENDBR: andw_ax_dx+0x0/0x10 [kvm]" issue was
> reproduced again after ran syzkaller 5min on ADL-P.
Ha, indeed :/
> > > +/*
> > > + * Create a dummy function pointer reference to prevent objtool from marking
> > > + * the function as needing to be "sealed" (i.e. ENDBR converted to NOP by
> > > + * apply_ibt_endbr()).
> > > + */
> > > +#define IBT_NOSEAL(fname) \
> > > + ".pushsection .discard.endbr.noseal\n\t" \
> > > + _ASM_PTR fname "\n\t" \
> > > + ".popsection\n\t"
> > > +
objtool/check.c:validate_ibt():
if (!strncmp(sec->name, ".discard", 8) ||
...)
continue;
So yeah, that'll just get ignored. So at the very least we need to
special case this section.
next prev parent reply other threads:[~2022-08-18 11:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <PH0PR11MB4839B4D2FB8B8D8D52A62C7F9A629@PH0PR11MB4839.namprd11.prod.outlook.com>
2022-08-17 10:56 ` [PATCH] x86/kvm, objtool: Avoid fastop ENDBR from being sealed Peter Zijlstra
2022-08-17 16:26 ` [tip: core/urgent] " tip-bot2 for Peter Zijlstra
2022-08-18 1:10 ` [PATCH] " Josh Poimboeuf
2022-08-18 7:28 ` Peter Zijlstra
2022-08-18 7:38 ` Pengfei Xu
2022-08-18 11:06 ` Peter Zijlstra [this message]
2022-08-18 15:17 ` Josh Poimboeuf
2022-08-18 5:04 ` Pengfei Xu
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