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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt4
-rw-r--r--kernel/rcu/rcu.h1
-rw-r--r--kernel/rcu/tree_stall.h4
-rw-r--r--kernel/rcu/update.c2
4 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 7ccd158b3894..f3fcd6140ee1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4047,6 +4047,10 @@
rcutorture.verbose= [KNL]
Enable additional printk() statements.
+ rcupdate.rcu_cpu_stall_ftrace_dump= [KNL]
+ Dump ftrace buffer after reporting RCU CPU
+ stall warning.
+
rcupdate.rcu_cpu_stall_suppress= [KNL]
Suppress RCU CPU stall warning messages.
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 5290b01de534..8fd4f82c9b3d 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -227,6 +227,7 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
#ifdef CONFIG_RCU_STALL_COMMON
+extern int rcu_cpu_stall_ftrace_dump;
extern int rcu_cpu_stall_suppress;
extern int rcu_cpu_stall_timeout;
int rcu_jiffies_till_stall_check(void);
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index 065183391f75..0627a66699a6 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -527,6 +527,8 @@ static void check_cpu_stall(struct rcu_data *rdp)
/* We haven't checked in, so go dump stack. */
print_cpu_stall();
+ if (rcu_cpu_stall_ftrace_dump)
+ rcu_ftrace_dump(DUMP_ALL);
} else if (rcu_gp_in_progress() &&
ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY) &&
@@ -534,6 +536,8 @@ static void check_cpu_stall(struct rcu_data *rdp)
/* They had a few time units to dump stack, so complain. */
print_other_cpu_stall(gs2);
+ if (rcu_cpu_stall_ftrace_dump)
+ rcu_ftrace_dump(DUMP_ALL);
}
}
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 61df2bf08563..249517058b13 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -437,6 +437,8 @@ EXPORT_SYMBOL_GPL(rcutorture_sched_setaffinity);
#endif
#ifdef CONFIG_RCU_STALL_COMMON
+int rcu_cpu_stall_ftrace_dump __read_mostly;
+module_param(rcu_cpu_stall_ftrace_dump, int, 0644);
int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */
EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress);
module_param(rcu_cpu_stall_suppress, int, 0644);