From: Sami Tolvanen <samitolvanen@google.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel test robot <oliver.sang@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Kees Cook <keescook@chromium.org>,
LKML <linux-kernel@vger.kernel.org>,
lkp@lists.01.org, kernel test robot <lkp@intel.com>
Subject: Re: [x86, build] 6dafca9780: WARNING:at_arch/x86/kernel/ftrace.c:#ftrace_verify_code
Date: Mon, 1 Mar 2021 19:23:03 -0800 [thread overview]
Message-ID: <CABCJKufOTubpoJyWQ5aMzgeiNsTRuO61T5FMEG=jFwnO0XZ-pQ@mail.gmail.com> (raw)
In-Reply-To: <20210301214702.1119c732@oasis.local.home>
On Mon, Mar 1, 2021 at 6:47 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Mon, 1 Mar 2021 18:40:32 -0800
> Sami Tolvanen <samitolvanen@google.com> wrote:
>
> > On Mon, Mar 01, 2021 at 08:15:26PM -0500, Steven Rostedt wrote:
> > > On Mon, 1 Mar 2021 16:03:51 -0800
> > > Sami Tolvanen <samitolvanen@google.com> wrote:
> > > >
> > > > > ret = ftrace_verify_code(rec->ip, old);
> > > > > +
> > > > > + if (__is_defined(CC_USING_NOP_MCOUNT) && ret && old_nop) {
> > > > > + /* Compiler could have put in P6_NOP5 */
> > > > > + old = P6_NOP5;
> > > > > + ret = ftrace_verify_code(rec->ip, old);
> > > > > + }
> > > > > +
> > > >
> > > > Wouldn't that still hit WARN(1) in the initial ftrace_verify_code()
> > > > call if ideal_nops doesn't match?
> > >
> > > That was too quickly written ;-)
> > >
> > > Take 2:
> > >
> > > [ with fixes for setting p6_nop ]
> >
> > Thanks, I tested this with the config from the build bot, and I can
> > confirm that it fixes the issue for me.
> >
> > I also tested a quick patch to disable the __fentry__ conversion in
> > objtool, and it seems to work too, but it's probably a good idea to
> > fix the issue with CC_USING_NOP_MCOUNT in any case.
>
> Thanks for testing, I'll make this into a proper patch and start
> testing it internally. I'm assuming you want this to go into the -rc
> release and possibly stable?
Sounds good, thank you. Yes, getting the fix to -rc would be great.
I'm not sure if it's necessary in -stable though, the objtool patch is
only in -rc1.
Sami
WARNING: multiple messages have this Message-ID (diff)
From: Sami Tolvanen <samitolvanen@google.com>
To: lkp@lists.01.org
Subject: Re: [x86, build] 6dafca9780: WARNING:at_arch/x86/kernel/ftrace.c:#ftrace_verify_code
Date: Mon, 01 Mar 2021 19:23:03 -0800 [thread overview]
Message-ID: <CABCJKufOTubpoJyWQ5aMzgeiNsTRuO61T5FMEG=jFwnO0XZ-pQ@mail.gmail.com> (raw)
In-Reply-To: <20210301214702.1119c732@oasis.local.home>
[-- Attachment #1: Type: text/plain, Size: 1667 bytes --]
On Mon, Mar 1, 2021 at 6:47 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Mon, 1 Mar 2021 18:40:32 -0800
> Sami Tolvanen <samitolvanen@google.com> wrote:
>
> > On Mon, Mar 01, 2021 at 08:15:26PM -0500, Steven Rostedt wrote:
> > > On Mon, 1 Mar 2021 16:03:51 -0800
> > > Sami Tolvanen <samitolvanen@google.com> wrote:
> > > >
> > > > > ret = ftrace_verify_code(rec->ip, old);
> > > > > +
> > > > > + if (__is_defined(CC_USING_NOP_MCOUNT) && ret && old_nop) {
> > > > > + /* Compiler could have put in P6_NOP5 */
> > > > > + old = P6_NOP5;
> > > > > + ret = ftrace_verify_code(rec->ip, old);
> > > > > + }
> > > > > +
> > > >
> > > > Wouldn't that still hit WARN(1) in the initial ftrace_verify_code()
> > > > call if ideal_nops doesn't match?
> > >
> > > That was too quickly written ;-)
> > >
> > > Take 2:
> > >
> > > [ with fixes for setting p6_nop ]
> >
> > Thanks, I tested this with the config from the build bot, and I can
> > confirm that it fixes the issue for me.
> >
> > I also tested a quick patch to disable the __fentry__ conversion in
> > objtool, and it seems to work too, but it's probably a good idea to
> > fix the issue with CC_USING_NOP_MCOUNT in any case.
>
> Thanks for testing, I'll make this into a proper patch and start
> testing it internally. I'm assuming you want this to go into the -rc
> release and possibly stable?
Sounds good, thank you. Yes, getting the fix to -rc would be great.
I'm not sure if it's necessary in -stable though, the objtool patch is
only in -rc1.
Sami
next prev parent reply other threads:[~2021-03-02 8:12 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 7:40 [x86, build] 6dafca9780: WARNING:at_arch/x86/kernel/ftrace.c:#ftrace_verify_code kernel test robot
2021-03-01 7:40 ` kernel test robot
2021-03-01 22:14 ` Sami Tolvanen
2021-03-01 22:14 ` Sami Tolvanen
2021-03-01 23:45 ` Steven Rostedt
2021-03-01 23:45 ` Steven Rostedt
2021-03-02 0:03 ` Sami Tolvanen
2021-03-02 0:03 ` Sami Tolvanen
2021-03-02 1:15 ` Steven Rostedt
2021-03-02 1:15 ` Steven Rostedt
2021-03-02 2:40 ` Sami Tolvanen
2021-03-02 2:40 ` Sami Tolvanen
2021-03-02 2:47 ` Steven Rostedt
2021-03-02 2:47 ` Steven Rostedt
2021-03-02 3:23 ` Sami Tolvanen [this message]
2021-03-02 3:23 ` Sami Tolvanen
2021-03-02 9:19 ` Peter Zijlstra
2021-03-02 9:19 ` Peter Zijlstra
2021-03-02 15:58 ` Steven Rostedt
2021-03-02 15:58 ` Steven Rostedt
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