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Commit dd9daa22 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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[PATCH] rcu_do_batch: make ->qlen decrement irq safe 



rcu_do_batch() decrements rdp->qlen with irqs enabled.  This is not good,
it can also be modified by call_rcu() from interrupt.

Decrement ->qlen once with irqs disabled, after a main loop.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7fbb3645

kernel/rcupdate.c

+5 −1
Original line number Diff line number Diff line
@@ -241,12 +241,16 @@ static void rcu_do_batch(struct rcu_data *rdp) 
		next = rdp->donelist = list->next;

		list->func(list);

		list = next;

		rdp->qlen--;

		if (++count >= rdp->blimit)

			break;

	}



	local_irq_disable();

	rdp->qlen -= count;

	local_irq_enable();

	if (rdp->blimit == INT_MAX && rdp->qlen <= qlowmark)

		rdp->blimit = blimit;



	if (!rdp->donelist)

		rdp->donetail = &rdp->donelist;

	else