From 82efed06d5e370f1526ec93ff4c2c2496542f615 Mon Sep 17 00:00:00 2001 From: Patrick Daly Date: Tue, 7 Apr 2015 15:12:07 -0700 Subject: [PATCH] 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: Patrick Daly Signed-off-by: Paul E. McKenney --- kernel/rcu/tree_plugin.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index f8af20273868..853c7b8ea833 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -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); -- 2.20.1