All of lore.kernel.org
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Holger Hoffstätte" <holger@applied-asynchrony.com>,
	"Qi Zheng" <zhengqi.arch@bytedance.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Justin Forbes" <jmforbes@linuxtx.org>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Guenter Roeck" <linux@roeck-us.net>,
	"Shuah Khan" <shuah@kernel.org>,
	patches@kernelci.org, lkft-triage@lists.linaro.org,
	"Pavel Machek" <pavel@denx.de>,
	"Jon Hunter" <jonathanh@nvidia.com>,
	"Florian Fainelli" <f.fainelli@gmail.com>,
	stable <stable@vger.kernel.org>,
	"Josh Poimboeuf" <jpoimboe@redhat.com>
Subject: Re: [PATCH 5.15 000/923] 5.15.3-rc3 review
Date: Thu, 18 Nov 2021 09:06:27 +0100	[thread overview]
Message-ID: <20211118080627.GH174703@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <CAHk-=wjHbKfck1Ws4Y0pUZ7bxdjU9eh2WK0EFsv65utfeVkT9Q@mail.gmail.com>

On Wed, Nov 17, 2021 at 03:50:17PM -0800, Linus Torvalds wrote:

> I really don't think the WCHAN code should use unwinders at all. It's
> too damn fragile, and it's too easily triggered from user space.

On x86, esp. with ORC, it pretty much has to. The thing is, the ORC
unwinder has been very stable so far. I'm guessing there's some really
stupid thing going on, like for example trying to unwind a freed stack.

I *just* managed to reproduce, so let me go have a poke.

> So I think we need to revert all the wchan changes. Not just in
> stable, but in mainline too.

Sure, we can do that. Want a pull request for that or will you just kill
them outright?

  parent reply	other threads:[~2021-11-18  8:06 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-17 10:19 [PATCH 5.15 000/923] 5.15.3-rc3 review Greg Kroah-Hartman
2021-11-17 13:37 ` Fox Chen
2021-11-17 14:13 ` Guenter Roeck
2021-11-17 14:43   ` Greg Kroah-Hartman
2021-11-17 14:54     ` Guenter Roeck
2021-11-17 17:34 ` Jon Hunter
2021-11-17 18:51 ` Florian Fainelli
2021-11-17 20:25 ` Holger Kiehl
2021-11-18  8:14   ` Greg Kroah-Hartman
2021-11-18 14:08     ` Holger Kiehl
2021-11-18 17:08       ` Greg Kroah-Hartman
2021-11-17 20:35 ` Guenter Roeck
2021-11-17 21:32 ` Justin Forbes
2021-11-17 23:32   ` Holger Hoffstätte
2021-11-17 23:50     ` Linus Torvalds
2021-11-18  0:16       ` Kees Cook
2021-11-18  6:26         ` Guenter Roeck
2021-11-18  8:14           ` Greg Kroah-Hartman
2021-11-18  8:12         ` Greg Kroah-Hartman
2021-11-18 17:17           ` Kees Cook
2021-11-18  8:06       ` Peter Zijlstra [this message]
2021-11-18  8:18         ` Peter Zijlstra
2021-11-18  9:39           ` Peter Zijlstra
2021-11-18 10:12             ` Peter Zijlstra
2021-11-18 12:11             ` Peter Zijlstra
2021-11-19  2:04               ` Josh Poimboeuf
2021-11-19  9:29                 ` [PATCH] x86: Pin task-stack in __get_wchan() Peter Zijlstra
2021-11-19 10:02                   ` Qi Zheng
2021-11-19 10:22                     ` Peter Zijlstra
2021-11-19 10:26                       ` Qi Zheng
2021-11-19 18:16                   ` Linus Torvalds
2021-11-19 18:35                   ` Josh Poimboeuf
2021-11-22  9:32                     ` Peter Zijlstra
2021-11-22 16:14                       ` Josh Poimboeuf
2021-11-18  5:45 ` [PATCH 5.15 000/923] 5.15.3-rc3 review Naresh Kamboju

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=20211118080627.GH174703@worktop.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=akpm@linux-foundation.org \
    --cc=f.fainelli@gmail.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=holger@applied-asynchrony.com \
    --cc=jmforbes@linuxtx.org \
    --cc=jonathanh@nvidia.com \
    --cc=jpoimboe@redhat.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@roeck-us.net \
    --cc=lkft-triage@lists.linaro.org \
    --cc=patches@kernelci.org \
    --cc=pavel@denx.de \
    --cc=shuah@kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    --cc=zhengqi.arch@bytedance.com \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.