From: Peter Zijlstra <peterz@infradead.org>
To: Kees Cook <keescook@chromium.org>
Cc: Jann Horn <jannh@google.com>,
Seth Jenkins <sethjenkins@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Andrew Morton <akpm@linux-foundation.org>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Eric Biggers <ebiggers@google.com>,
Huang Ying <ying.huang@intel.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-doc@vger.kernel.org,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
Joel Savitz <jsavitz@redhat.com>,
Laurent Dufour <ldufour@linux.ibm.com>,
Rob Herring <robh@kernel.org>, Al Viro <viro@zeniv.linux.org.uk>,
Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] exit: Allow oops_limit to be disabled
Date: Fri, 16 Dec 2022 15:05:13 +0100 [thread overview]
Message-ID: <Y5x7GXeluFmZ8E0E@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20221202210617.never.105-kees@kernel.org>
On Fri, Dec 02, 2022 at 01:06:21PM -0800, Kees Cook wrote:
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -954,7 +954,7 @@ void __noreturn make_task_dead(int signr)
> * To make sure this can't happen, place an upper bound on how often the
> * kernel may oops without panic().
> */
> - if (atomic_inc_return(&oops_count) >= READ_ONCE(oops_limit))
> + if (atomic_inc_return(&oops_count) >= READ_ONCE(oops_limit) && oops_limit)
> panic("Oopsed too often (kernel.oops_limit is %d)", oops_limit);
>
That's dodgy, please write as:
limit = READ_ONCE(oops_limit);
if (atomic_inc_return(&oops_count) >= limit && limit)
So we don't explicitly add a reload that negates the whole READ_ONCE().
next prev parent reply other threads:[~2022-12-16 14:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-02 21:06 Kees Cook
2022-12-16 14:05 ` Peter Zijlstra [this message]
2022-12-16 20:32 ` Kees Cook
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=Y5x7GXeluFmZ8E0E@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=Jason@zx2c4.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=baolin.wang@linux.alibaba.com \
--cc=corbet@lwn.net \
--cc=ebiederm@xmission.com \
--cc=ebiggers@google.com \
--cc=gpiccoli@igalia.com \
--cc=jannh@google.com \
--cc=jsavitz@redhat.com \
--cc=keescook@chromium.org \
--cc=ldufour@linux.ibm.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=robh@kernel.org \
--cc=sethjenkins@google.com \
--cc=viro@zeniv.linux.org.uk \
--cc=ying.huang@intel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®