netdev, sched/wait: Fix sleeping inside wait event (ff960a73) · Commits · 戴 / test

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. Reported-by:

Fengguang Wu <fengguang.wu@intel.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:

David S. Miller <davem@davemloft.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Cong Wang <cwang@twopensource.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jerry Chu <hkchu@google.com> Cc: Jiri Pirko <jiri@resnulli.us> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com> Cc: sfeldma@cumulusnetworks.com <sfeldma@cumulusnetworks.com> Cc: stephen hemminger <stephen@networkplumber.org> Cc: Tom Gundersen <teg@jklm.no> Cc: Tom Herbert <therbert@google.com> Cc: Veaceslav Falico <vfalico@gmail.com> Cc: Vlad Yasevich <vyasevic@redhat.com> Cc: netdev@vger.kernel.org Link: http://lkml.kernel.org/r/20141029173110.GE15602@worktop.programming.kicks-ass.net Signed-off-by:

Ingo Molnar <mingo@kernel.org>

net/core/dev.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -7196,11 +7196,10 @@ static void __net_exit rtnl_lock_unregistering(struct list_head *net_list)
		*/
		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_unregistering(struct list_head *net_list)
		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)

net/core/rtnetlink.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -365,11 +365,10 @@ static void rtnl_lock_unregistering_all(void)
		{
		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(void)
		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);
		}

		/**

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