From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jann Horn <jannh@google.com>, Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
the arch/x86 maintainers <x86@kernel.org>,
kernel list <linux-kernel@vger.kernel.org>,
alexandre.chartre@oracle.com
Subject: Re: x86 entry perf unwinding failure (missing IRET_REGS annotation on stack switch?)
Date: Tue, 28 Apr 2020 10:54:13 -0500 [thread overview]
Message-ID: <20200428155413.b5xzef4s2kyzg5ed@treble> (raw)
In-Reply-To: <20200428154909.4cjwetyyb2zhnq5i@treble>
On Tue, Apr 28, 2020 at 10:49:09AM -0500, Josh Poimboeuf wrote:
> On Tue, Apr 28, 2020 at 05:25:52PM +0200, Peter Zijlstra wrote:
> > On Tue, Apr 28, 2020 at 09:31:57AM -0500, Josh Poimboeuf wrote:
> > > That's quite the monstrosity, and I still don't see the point. I
> > > thought we decided to just disallow CFI changes in alternatives anyway?
> > > That can be done much simpler.
> >
> > Something like so then ?
> >
> > ---
> > diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> > index 8443ec690051..d14d83e6edb0 100644
> > --- a/tools/objtool/check.c
> > +++ b/tools/objtool/check.c
> > @@ -940,6 +940,7 @@ static int handle_group_alt(struct objtool_file *file,
> >
> > last_new_insn = insn;
> >
> > + insn->alt_group = true;
> > insn->ignore = orig_insn->ignore_alts;
> > insn->func = orig_insn->func;
> >
> > @@ -2242,6 +2243,11 @@ static int handle_insn_ops(struct instruction *insn, struct insn_state *state)
> > list_for_each_entry(op, &insn->stack_ops, list) {
> > int res;
> >
> > + if (insn->alt_group) {
> > + WARN_FUNC("alternative has CFI", insn->sec, insn->offset);
> > + return 1;
> > + }
> > +
>
> ACK (separate patch)
BTW, since most people don't know what CFI is, how about something like
"unsupported stack change in alternatives code"
--
Josh
next prev parent reply other threads:[~2020-04-28 15:54 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-01 6:02 x86 entry perf unwinding failure (missing IRET_REGS annotation on stack switch?) Jann Horn
2020-03-02 14:58 ` Peter Zijlstra
2020-03-02 15:18 ` Josh Poimboeuf
2020-03-02 15:52 ` Josh Poimboeuf
2020-04-28 7:04 ` Josh Poimboeuf
2020-04-28 12:46 ` Peter Zijlstra
2020-04-28 14:14 ` Josh Poimboeuf
2020-04-28 14:35 ` Peter Zijlstra
2020-04-28 14:16 ` Peter Zijlstra
2020-04-28 14:31 ` Josh Poimboeuf
2020-04-28 15:25 ` Peter Zijlstra
2020-04-28 15:49 ` Josh Poimboeuf
2020-04-28 15:54 ` Josh Poimboeuf [this message]
2020-04-28 16:25 ` Sean Christopherson
2020-04-28 16:33 ` Josh Poimboeuf
2020-04-28 18:28 ` Peter Zijlstra
2020-04-28 16:44 ` Peter Zijlstra
2020-04-28 17:01 ` Josh Poimboeuf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200428155413.b5xzef4s2kyzg5ed@treble \
--to=jpoimboe@redhat.com \
--cc=alexandre.chartre@oracle.com \
--cc=bp@alien8.de \
--cc=hpa@zytor.com \
--cc=jannh@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).