From: Peter Zijlstra <peterz@infradead.org>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>, LKP <lkp@01.org>,
LKML <linux-kernel@vger.kernel.org>,
"oleg@redhat.com" <oleg@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
David Miller <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: [PATCH] netdev: Fix sleeping inside wait event
Date: Wed, 29 Oct 2014 18:31:10 +0100 [thread overview]
Message-ID: <20141029173110.GE15602@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20141029171345.GO12706@worktop.programming.kicks-ass.net>
On Wed, Oct 29, 2014 at 06:13:45PM +0100, Peter Zijlstra wrote:
> On Wed, Oct 29, 2014 at 09:29:55AM -0700, Cong Wang wrote:
> > While you are on it, please fix rtnl_lock_unregistering_all() too?
>
> Ah, that's hidden someplace else, sure I can do that. Thanks for
> pointing it out.
Here goes..
---
Subject: netdev: Fix sleeping inside wait event
From: Peter Zijlstra <peterz@infradead.org>
Date: Wed Oct 29 17:04:56 CET 2014
rtnl_lock_unregistering*() take rtnl_lock() -- a mutex -- inside a
wait loop. The wait loop relies on current->state to function, but so
does mutex_lock(), nesting them makes for the inner to destroy the
outer state.
Fix this using the new wait_woken() bits.
Cc: David Miller <davem@davemloft.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
net/core/dev.c | 10 +++++-----
net/core/rtnetlink.c | 10 +++++-----
2 files changed, 10 insertions(+), 10 deletions(-)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7196,11 +7196,10 @@ static void __net_exit rtnl_lock_unregis
*/
struct net *net;
bool unregistering;
- DEFINE_WAIT(wait);
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+ add_wait_queue(&netdev_unregistering_wq, &wait);
for (;;) {
- prepare_to_wait(&netdev_unregistering_wq, &wait,
- TASK_UNINTERRUPTIBLE);
unregistering = false;
rtnl_lock();
list_for_each_entry(net, net_list, exit_list) {
@@ -7212,9 +7211,10 @@ static void __net_exit rtnl_lock_unregis
if (!unregistering)
break;
__rtnl_unlock();
- schedule();
+
+ wait_woken(&wait, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
}
- finish_wait(&netdev_unregistering_wq, &wait);
+ remove_wait_queue(&netdev_unregistering_wq, &wait);
}
static void __net_exit default_device_exit_batch(struct list_head *net_list)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -365,11 +365,10 @@ static void rtnl_lock_unregistering_all(
{
struct net *net;
bool unregistering;
- DEFINE_WAIT(wait);
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+ add_wait_queue(&netdev_unregistering_wq, &wait);
for (;;) {
- prepare_to_wait(&netdev_unregistering_wq, &wait,
- TASK_UNINTERRUPTIBLE);
unregistering = false;
rtnl_lock();
for_each_net(net) {
@@ -381,9 +380,10 @@ static void rtnl_lock_unregistering_all(
if (!unregistering)
break;
__rtnl_unlock();
- schedule();
+
+ wait_woken(&wait, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
}
- finish_wait(&netdev_unregistering_wq, &wait);
+ remove_wait_queue(&netdev_unregistering_wq, &wait);
}
/**
next prev parent reply other threads:[~2014-10-29 17:31 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-28 14:25 WARNING: CPU: 0 PID: 61 at kernel/sched/core.c:7312 __might_sleep() Fengguang Wu
2014-10-29 16:16 ` [PATCH] netdev: Fix sleeping inside wait event Peter Zijlstra
2014-10-29 16:29 ` Cong Wang
2014-10-29 17:13 ` Peter Zijlstra
2014-10-29 17:31 ` Peter Zijlstra [this message]
2014-10-29 17:38 ` David Miller
2014-11-04 16:09 ` [tip:sched/core] netdev, sched/wait: " tip-bot for Peter Zijlstra
2014-10-29 17:37 ` [PATCH] netdev: " David Miller
2015-02-01 3:43 ` __might_sleep() warnings on v3.19-rc6 Fengguang Wu
2015-02-01 23:03 ` NeilBrown
2015-02-02 4:58 ` NeilBrown
2015-02-02 5:08 ` Linus Torvalds
2015-02-02 6:09 ` NeilBrown
2015-02-05 16:16 ` Chris Mason
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=20141029173110.GE15602@worktop.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=davem@davemloft.net \
--cc=ebiederm@xmission.com \
--cc=fengguang.wu@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@01.org \
--cc=netdev@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=xiyou.wangcong@gmail.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;
as well as URLs for NNTP newsgroup(s).