From: Linus Torvalds <torvalds@linux-foundation.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Boqun Feng <boqun.feng@gmail.com>,
Fengguang Wu <fengguang.wu@intel.com>, LKP <lkp@01.org>,
LKML <linux-kernel@vger.kernel.org>,
Netdev <netdev@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: rcu_read_lock lost its compiler barrier
Date: Sun, 2 Jun 2019 13:54:12 -0700 [thread overview]
Message-ID: <CAHk-=whLGKOmM++OQi5GX08_dfh8Xfz9Wq7khPo+MVtPYh_8hw@mail.gmail.com> (raw)
In-Reply-To: <20190602055607.bk5vgmwjvvt4wejd@gondor.apana.org.au>
On Sat, Jun 1, 2019 at 10:56 PM Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> You can't then go and decide to remove the compiler barrier! To do
> that you'd need to audit every single use of rcu_read_lock in the
> kernel to ensure that they're not depending on the compiler barrier.
What's the possible case where it would matter when there is no preemption?
Linus
WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: lkp@lists.01.org
Subject: Re: rcu_read_lock lost its compiler barrier
Date: Sun, 02 Jun 2019 13:54:12 -0700 [thread overview]
Message-ID: <CAHk-=whLGKOmM++OQi5GX08_dfh8Xfz9Wq7khPo+MVtPYh_8hw@mail.gmail.com> (raw)
In-Reply-To: <20190602055607.bk5vgmwjvvt4wejd@gondor.apana.org.au>
[-- Attachment #1: Type: text/plain, Size: 394 bytes --]
On Sat, Jun 1, 2019 at 10:56 PM Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> You can't then go and decide to remove the compiler barrier! To do
> that you'd need to audit every single use of rcu_read_lock in the
> kernel to ensure that they're not depending on the compiler barrier.
What's the possible case where it would matter when there is no preemption?
Linus
next prev parent reply other threads:[~2019-06-02 21:02 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-10 0:57 [rcu] kernel BUG at include/linux/pagemap.h:149! Fengguang Wu
2015-09-10 0:57 ` Fengguang Wu
2015-09-10 10:25 ` Boqun Feng
2015-09-10 17:16 ` Paul E. McKenney
2015-09-10 17:16 ` Paul E. McKenney
2015-09-11 2:19 ` Boqun Feng
[not found] ` <CAJzB8QG=1iZW3dQEie6ZSTLv8GZ3YSut0aL1VU7LLmiHQ1B1DQ@mail.gmail.com>
2015-09-11 21:59 ` Paul E. McKenney
2015-09-11 21:59 ` Paul E. McKenney
2015-09-12 5:46 ` Boqun Feng
2015-09-21 19:30 ` Frederic Weisbecker
2015-09-21 19:30 ` Frederic Weisbecker
2015-09-21 20:43 ` Paul E. McKenney
2015-09-21 20:43 ` Paul E. McKenney
2019-06-02 5:56 ` rcu_read_lock lost its compiler barrier Herbert Xu
2019-06-02 5:56 ` Herbert Xu
2019-06-02 20:54 ` Linus Torvalds [this message]
2019-06-02 20:54 ` Linus Torvalds
2019-06-03 2:46 ` Herbert Xu
2019-06-03 2:46 ` Herbert Xu
2019-06-03 3:47 ` Paul E. McKenney
2019-06-03 4:01 ` Herbert Xu
2019-06-03 4:01 ` Herbert Xu
2019-06-03 4:17 ` Herbert Xu
2019-06-03 4:17 ` Herbert Xu
2019-06-03 7:23 ` Paul E. McKenney
2019-06-03 8:42 ` Paul E. McKenney
2019-06-03 15:26 ` David Laight
2019-06-03 15:40 ` Linus Torvalds
2019-06-03 15:40 ` Linus Torvalds
2019-06-03 5:26 ` Herbert Xu
2019-06-03 5:26 ` Herbert Xu
2019-06-03 6:42 ` Boqun Feng
2019-06-03 6:42 ` Boqun Feng
2019-06-03 20:03 ` Paul E. McKenney
2019-06-04 14:44 ` Alan Stern
2019-06-04 14:44 ` Alan Stern
2019-06-04 16:04 ` Linus Torvalds
2019-06-04 16:04 ` Linus Torvalds
2019-06-04 17:00 ` Alan Stern
2019-06-04 17:00 ` Alan Stern
2019-06-04 17:29 ` Linus Torvalds
2019-06-04 17:29 ` Linus Torvalds
2019-06-07 14:09 ` inet: frags: Turn fqdir->dead into an int for old Alphas Herbert Xu
2019-06-07 14:09 ` Herbert Xu
2019-06-07 15:26 ` Eric Dumazet
2019-06-07 15:26 ` Eric Dumazet
2019-06-07 15:32 ` Herbert Xu
2019-06-07 15:32 ` Herbert Xu
2019-06-07 16:13 ` Eric Dumazet
2019-06-07 16:13 ` Eric Dumazet
2019-06-07 16:19 ` Linus Torvalds
2019-06-07 16:19 ` Linus Torvalds
2019-06-08 15:27 ` Paul E. McKenney
2019-06-08 17:42 ` Linus Torvalds
2019-06-08 17:42 ` Linus Torvalds
2019-06-08 17:50 ` Linus Torvalds
2019-06-08 17:50 ` Linus Torvalds
2019-06-08 18:50 ` Paul E. McKenney
2019-06-08 18:14 ` Paul E. McKenney
2019-06-06 4:51 ` rcu_read_lock lost its compiler barrier Herbert Xu
2019-06-06 4:51 ` Herbert Xu
2019-06-06 6:05 ` Paul E. McKenney
2019-06-06 6:14 ` Herbert Xu
2019-06-06 6:14 ` Herbert Xu
2019-06-06 9:06 ` Paul E. McKenney
2019-06-06 9:28 ` Herbert Xu
2019-06-06 9:28 ` Herbert Xu
2019-06-06 10:58 ` Paul E. McKenney
2019-06-06 13:38 ` Herbert Xu
2019-06-06 13:38 ` Herbert Xu
2019-06-06 13:48 ` Paul E. McKenney
2019-06-06 8:16 ` Andrea Parri
2019-06-06 14:19 ` Alan Stern
2019-06-06 14:19 ` Alan Stern
2019-06-08 15:19 ` Paul E. McKenney
2019-06-08 15:56 ` Alan Stern
2019-06-08 15:56 ` Alan Stern
2019-06-08 16:31 ` Paul E. McKenney
2019-06-03 9:35 ` Paul E. McKenney
2019-06-06 8:38 ` Andrea Parri
2019-06-06 9:32 ` Herbert Xu
2019-06-06 9:32 ` Herbert Xu
2019-06-03 0:06 ` Paul E. McKenney
2019-06-03 3:03 ` Herbert Xu
2019-06-03 3:03 ` Herbert Xu
2019-06-03 9:27 ` Paul E. McKenney
2019-06-03 15:55 ` Linus Torvalds
2019-06-03 15:55 ` Linus Torvalds
2019-06-03 16:07 ` Linus Torvalds
2019-06-03 16:07 ` Linus Torvalds
2019-06-03 19:53 ` Paul E. McKenney
2019-06-03 20:24 ` Linus Torvalds
2019-06-03 20:24 ` Linus Torvalds
2019-06-04 21:14 ` Paul E. McKenney
2019-06-05 2:21 ` Herbert Xu
2019-06-05 2:21 ` Herbert Xu
2019-06-05 3:30 ` Paul E. McKenney
2019-06-06 4:37 ` Herbert Xu
2019-06-06 4:37 ` Herbert Xu
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='CAHk-=whLGKOmM++OQi5GX08_dfh8Xfz9Wq7khPo+MVtPYh_8hw@mail.gmail.com' \
--to=torvalds@linux-foundation.org \
--cc=boqun.feng@gmail.com \
--cc=davem@davemloft.net \
--cc=fengguang.wu@intel.com \
--cc=fweisbec@gmail.com \
--cc=herbert@gondor.apana.org.au \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@01.org \
--cc=netdev@vger.kernel.org \
--cc=paulmck@linux.vnet.ibm.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.