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-rw-r--r--include/linux/sched.h2
-rw-r--r--kernel/rcutree.c25
-rw-r--r--kernel/sched/core.c6
3 files changed, 32 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0dd42a02df2..ba69b5adea3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -109,6 +109,8 @@ extern void update_cpu_load_nohz(void);
extern unsigned long get_parent_ip(unsigned long addr);
+extern void dump_cpu_task(int cpu);
+
struct seq_file;
struct cfs_rq;
struct task_group;
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 74df86bd920..e78538712df 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -873,6 +873,29 @@ static void record_gp_stall_check_time(struct rcu_state *rsp)
rsp->jiffies_stall = jiffies + jiffies_till_stall_check();
}
+/*
+ * Dump stacks of all tasks running on stalled CPUs. This is a fallback
+ * for architectures that do not implement trigger_all_cpu_backtrace().
+ * The NMI-triggered stack traces are more accurate because they are
+ * printed by the target CPU.
+ */
+static void rcu_dump_cpu_stacks(struct rcu_state *rsp)
+{
+ int cpu;
+ unsigned long flags;
+ struct rcu_node *rnp;
+
+ rcu_for_each_leaf_node(rsp, rnp) {
+ raw_spin_lock_irqsave(&rnp->lock, flags);
+ if (rnp->qsmask != 0) {
+ for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++)
+ if (rnp->qsmask & (1UL << cpu))
+ dump_cpu_task(rnp->grplo + cpu);
+ }
+ raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ }
+}
+
static void print_other_cpu_stall(struct rcu_state *rsp)
{
int cpu;
@@ -929,7 +952,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
if (ndetected == 0)
printk(KERN_ERR "INFO: Stall ended before state dump start\n");
else if (!trigger_all_cpu_backtrace())
- dump_stack();
+ rcu_dump_cpu_stacks(rsp);
/* Complain about tasks blocking the grace period. */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2d8927fda71..59d08fb1a9e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8076,3 +8076,9 @@ struct cgroup_subsys cpuacct_subsys = {
.base_cftypes = files,
};
#endif /* CONFIG_CGROUP_CPUACCT */
+
+void dump_cpu_task(int cpu)
+{
+ pr_info("Task dump for CPU %d:\n", cpu);
+ sched_show_task(cpu_curr(cpu));
+}