From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Oleksandr Natalenko" <oleksandr@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-fsdevel@vger.kernel.org, "Jonathan Corbet" <corbet@lwn.net>,
"Alexander Viro" <viro@zeniv.linux.org.uk>,
"Huang Ying" <ying.huang@intel.com>,
"Jason A . Donenfeld" <Jason@zx2c4.com>,
"Will Deacon" <will@kernel.org>,
"Guilherme G . Piccoli" <gpiccoli@igalia.com>,
"Laurent Dufour" <ldufour@linux.ibm.com>,
"Stephen Kitt" <steve@sk2.org>, "Rob Herring" <robh@kernel.org>,
"Joel Savitz" <jsavitz@redhat.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
"Kees Cook" <keescook@chromium.org>,
"Xiaoming Ni" <nixiaoming@huawei.com>,
"Luis Chamberlain" <mcgrof@kernel.org>,
"Renaud Métrich" <rmetrich@redhat.com>,
"Grzegorz Halat" <ghalat@redhat.com>, "Qi Guo" <qguo@redhat.com>
Subject: Re: [PATCH] core_pattern: add CPU specifier
Date: Sun, 4 Sep 2022 21:38:44 +0200 [thread overview]
Message-ID: <20220904193844.GA7953@redhat.com> (raw)
In-Reply-To: <20220904112718.b7feead47012600ef255dfdf@linux-foundation.org>
On 09/04, Andrew Morton wrote:
>
> On Sat, 3 Sep 2022 08:43:30 +0200 Oleksandr Natalenko <oleksandr@redhat.com> wrote:
>
> > @@ -535,6 +539,7 @@ void do_coredump(const kernel_siginfo_t *siginfo)
> > */
> > .mm_flags = mm->flags,
> > .vma_meta = NULL,
> > + .cpu = raw_smp_processor_id(),
> > };
>
> Why use the "raw_" function here?
To avoid check_preemption_disabled() from debug_smp_processor_id().
We do not disable preemption because this is pointless, this is the
"racy snapshot" anyway. The coredumping task can migrate to another
CPU even before get_signal/do_coredump, right after exit-to-user
path enables irqs.
Oleg.
next prev parent reply other threads:[~2022-09-04 19:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-03 6:43 [PATCH] core_pattern: add CPU specifier Oleksandr Natalenko
2022-09-03 7:20 ` Oleg Nesterov
2022-09-04 18:27 ` Andrew Morton
2022-09-04 19:38 ` Oleg Nesterov [this message]
2022-09-06 22:22 ` Eric W. Biederman
2022-09-07 6:15 ` Oleksandr Natalenko
2022-09-07 17:34 ` Oleg Nesterov
2022-09-07 22:00 ` Eric W. Biederman
2022-09-08 6:11 ` Oleksandr Natalenko
2022-09-07 15:53 ` Luis Chamberlain
2022-09-08 6:45 ` Renaud Métrich
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