Function trigger_all_cpu_backtrace() uses NMI to dump the stack traces
of other CPU, it should actually be one of the ways to implement
dump_cpu_task(). So try it first in dump_cpu_task(). At the same time,
unnecessary duplicate code of upper-layer functions is eliminated.
There is also a call to dump_cpu_task() in
synchronize_rcu_expedited_wait(), which should also try to use NMI to
dump the stack traces first. It is currently the result of this
adjustment, so leave it unchanged.
Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
---
kernel/rcu/tree_stall.h | 8 +++-----
kernel/sched/core.c | 3 +++
kernel/smp.c | 3 +--
3 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index a001e1e7a99269c..80749d257ac2f78 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -368,7 +368,7 @@ static void rcu_dump_cpu_stacks(void)
if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) {
if (cpu_is_offline(cpu))
pr_err("Offline CPU %d blocking current GP.\n", cpu);
- else if (!trigger_single_cpu_backtrace(cpu))
+ else
dump_cpu_task(cpu);
}
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@@ -486,8 +486,7 @@ static void rcuc_kthread_dump(struct rcu_data *rdp)
pr_err("%s kthread starved for %ld jiffies\n", rcuc->comm, j);
sched_show_task(rcuc);
- if (!trigger_single_cpu_backtrace(cpu))
- dump_cpu_task(cpu);
+ dump_cpu_task(cpu);
}
/* Complain about starvation of grace-period kthread. */
@@ -515,8 +514,7 @@ static void rcu_check_gp_kthread_starvation(void)
pr_err("RCU GP kthread last ran on offline CPU %d.\n", cpu);
} else {
pr_err("Stack dump where RCU GP kthread last ran:\n");
- if (!trigger_single_cpu_backtrace(cpu))
- dump_cpu_task(cpu);
+ dump_cpu_task(cpu);
}
}
wake_up_process(gpk);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index df8fe433642fa30..0e82073020bf0d1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -11145,6 +11145,9 @@ struct cgroup_subsys cpu_cgrp_subsys = {
void dump_cpu_task(int cpu)
{
+ if (trigger_single_cpu_backtrace(cpu))
+ return;
+
pr_info("Task dump for CPU %d:\n", cpu);
sched_show_task(cpu_curr(cpu));
}
diff --git a/kernel/smp.c b/kernel/smp.c
index dd215f439426449..56ca958364aebeb 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -370,8 +370,7 @@ static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 *
if (cpu >= 0) {
if (static_branch_unlikely(&csdlock_debug_extended))
csd_lock_print_extended(csd, cpu);
- if (!trigger_single_cpu_backtrace(cpu))
- dump_cpu_task(cpu);
+ dump_cpu_task(cpu);
if (!cpu_cur_csd) {
pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu);
arch_send_call_function_single_ipi(cpu);
--
2.25.1
