From: "Paul E. McKenney" <paulmck@linux.ibm.com>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@linux.ibm.com>
Subject: [PATCH tip/core/rcu 04/12] rcu: Add kernel parameter to dump trace after RCU CPU stall warning
Date: Thu, 1 Aug 2019 15:37:39 -0700 [thread overview]
Message-ID: <20190801223747.15560-4-paulmck@linux.ibm.com> (raw)
In-Reply-To: <20190801223708.GA14862@linux.ibm.com>
This commit adds a rcu_cpu_stall_ftrace_dump kernel boot parameter, that,
when set, causes the trace buffer to be dumped after an RCU CPU stall
warning is printed. This kernel boot parameter is disabled by default,
maintaining compatibility with previous behavior.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
---
Documentation/admin-guide/kernel-parameters.txt | 4 ++++
kernel/rcu/rcu.h | 1 +
kernel/rcu/tree_stall.h | 4 ++++
kernel/rcu/update.c | 2 ++
4 files changed, 11 insertions(+)
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);
--
2.17.1
next prev parent reply other threads:[~2019-08-01 22:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 22:37 [PATCH tip/core/rcu 0/12] Miscellaneous fixes for v5.4 Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 01/12] lockdep: Make print_lock() address visible Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 02/12] time/tick-broadcast: Fix tick_broadcast_offline() lockdep complaint Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 03/12] rcu: Restore barrier() to rcu_read_lock() and rcu_read_unlock() Paul E. McKenney
2019-08-01 22:37 ` Paul E. McKenney [this message]
2019-08-01 22:37 ` [PATCH tip/core/rcu 05/12] rcu: Add destroy_work_on_stack() to match INIT_WORK_ONSTACK() Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 06/12] srcu: Avoid srcutorture security-based pointer obfuscation Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 07/12] rcu: Change return type of rcu_spawn_one_boost_kthread() Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 08/12] doc: Add rcutree.kthread_prio pointer to stallwarn.txt Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 09/12] idle: Prevent late-arriving interrupts from disrupting offline Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 10/12] rcu: Remove redundant "if" condition from rcu_gp_is_expedited() Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 11/12] arm: Use common outgoing-CPU-notification code Paul E. McKenney
2019-08-01 22:37 ` [PATCH tip/core/rcu 12/12] rcu: Fix spelling mistake "greate"->"great" Paul E. McKenney
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