Commit-ID: 0032f4e889764d22ccccb6a15742071d6f0d1f5a
Gitweb: https://git.kernel.org/tip/0032f4e889764d22ccccb6a15742071d6f0d1f5a
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Wed, 30 Aug 2017 10:40:17 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Mon, 9 Oct 2017 14:26:09 -0700
rcutorture: Dump writer stack if stalled
Right now, rcutorture warns if an rcu_torture_writer() kthread stalls,
but this warning is not always all that helpful. This commit therefore
makes the first such warning include a stack dump.
This in turn requires that sched_show_task() be exported to GPL modules,
so this commit makes that change as well.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/rcutorture.c | 6 ++++++
kernel/sched/core.c | 1 +
2 files changed, 7 insertions(+)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 0273bc0..362eb2f 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -51,6 +51,7 @@
#include <asm/byteorder.h>
#include <linux/torture.h>
#include <linux/vmalloc.h>
+#include <linux/sched/debug.h>
#include "rcu.h"
@@ -1240,6 +1241,7 @@ rcu_torture_stats_print(void)
long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
static unsigned long rtcv_snap = ULONG_MAX;
+ static bool splatted;
struct task_struct *wtp;
for_each_possible_cpu(cpu) {
@@ -1325,6 +1327,10 @@ rcu_torture_stats_print(void)
gpnum, completed, flags,
wtp == NULL ? ~0UL : wtp->state,
wtp == NULL ? -1 : (int)task_cpu(wtp));
+ if (!splatted && wtp) {
+ sched_show_task(wtp);
+ splatted = true;
+ }
show_rcu_gp_kthreads();
rcu_ftrace_dump(DUMP_ALL);
}
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d17c5da..7ae0151 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5165,6 +5165,7 @@ void sched_show_task(struct task_struct *p)
show_stack(p, NULL);
put_task_stack(p);
}
+EXPORT_SYMBOL_GPL(sched_show_task);
static inline bool
state_filter_match(unsigned long state_filter, struct task_struct *p)
--
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