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Commit 82efed06 authored by Patrick Daly's avatar Patrick Daly Committed by Paul E. McKenney
Browse files

rcu: Fix missing task information during rcu-preempt stall 



The first item list_for_each_entry_continue(alist) iterates over is
alist->next, rather than alist itself. Consequently,
rcu_print_detail_task_stall_rnp() skips the task referenced by gp_tasks.

Use gp_tasks->prev as the argument to list_for_each_entry_continue()
instead.

Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent a76ff688

kernel/rcu/tree_plugin.h

+2 −2
Original line number Diff line number Diff line
@@ -395,7 +395,7 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp) 
		raw_spin_unlock_irqrestore(&rnp->lock, flags);

		return;

	}

	t = list_entry(rnp->gp_tasks,

	t = list_entry(rnp->gp_tasks->prev,

		       struct task_struct, rcu_node_entry);

	list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry)

		sched_show_task(t);
@@ -452,7 +452,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp) 
	if (!rcu_preempt_blocked_readers_cgp(rnp))

		return 0;

	rcu_print_task_stall_begin(rnp);

	t = list_entry(rnp->gp_tasks,

	t = list_entry(rnp->gp_tasks->prev,

		       struct task_struct, rcu_node_entry);

	list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {

		pr_cont(" P%d", t->pid);