From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>,
syzbot <syzbot+84fe685c02cd112a2ac3@syzkaller.appspotmail.com>,
bp@alien8.de, hpa@zytor.com, inglorion@google.com,
linux-kernel@vger.kernel.org, mingo@redhat.com,
syzkaller-bugs@googlegroups.com, tglx@linutronix.de,
x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [syzbot] KASAN: stack-out-of-bounds Read in profile_pc
Date: Thu, 3 Jun 2021 08:39:14 -0500 [thread overview]
Message-ID: <20210603133914.j2aeadmvhncnlk5q@treble> (raw)
In-Reply-To: <YLjZYvXnuPnbXzOm@hirez.programming.kicks-ass.net>
On Thu, Jun 03, 2021 at 03:30:10PM +0200, Peter Zijlstra wrote:
> On Wed, Jun 02, 2021 at 04:35:11PM -0700, Andi Kleen wrote:
>
> > > We could just use ORC to unwind to the next frame. Though, isn't
> > > /proc/profile redundant, compared to all the more sophisticated options
> > > nowadays? Is there still a distinct use case for it or can we just
> > > remove it?
> >
> > It's still needed for some special cases. For example there is no other
> > viable way to profile early boot without a VM
> >
> > I would just drop the hack to unwind, at least for the early boot profile
> > use case locking profiling is usually not needed.
>
> Surely we can cook up something else there and delete this thing? ftrace
> buffers are available really early, it shouldn't be hard to dump some
> data in there during boot.
True, ftrace does have function profiling (function_profile_enabled).
Steve, is there a way to enable that on the kernel cmdline?
--
Josh
next prev parent reply other threads:[~2021-06-03 13:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 7:15 syzbot
2021-06-02 23:00 ` Josh Poimboeuf
2021-06-02 23:35 ` Andi Kleen
2021-06-03 13:29 ` Josh Poimboeuf
2021-06-03 13:30 ` Peter Zijlstra
2021-06-03 13:39 ` Josh Poimboeuf [this message]
2021-06-03 13:52 ` Andi Kleen
2021-10-11 13:07 ` Lee Jones
2021-10-11 14:43 ` Steven Rostedt
2021-10-11 17:10 ` Dmitry Vyukov
2021-10-11 17:30 ` Josh Poimboeuf
2021-06-03 8:02 ` syzbot
2024-08-01 3:16 ` [syzbot] [kernel?] " syzbot
2024-10-27 10:15 ` Tetsuo Handa
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