From: Boqun Feng <boqun.feng@gmail.com>
To: linux-kernel@vger.kernel.org, rcu@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
Uladzislau Rezki <urezki@gmail.com>,
Boqun Feng <boqun.feng@gmail.com>
Subject: [RFC lockdep 3/4] rcu/lockdep: Annotate the rcu_callback_map with proper wait contexts
Date: Tue, 8 Dec 2020 18:31:11 +0800 [thread overview]
Message-ID: <20201208103112.2838119-4-boqun.feng@gmail.com> (raw)
In-Reply-To: <20201208103112.2838119-1-boqun.feng@gmail.com>
rcu_callback_map is a virtual lock to annotate a context where RCU
callbacks are executed. RCU callbacks are required in softirq disable
contexts because with some config combination (use_softirq is true and
nocb is disabled) RCU callbacks only execute in softirq contexts.
Therefore wait context annotations can be added to detect bugs like
using mutex in a RCU callback.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
kernel/rcu/update.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 39334d2d2b37..dd59e6412f61 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -269,8 +269,12 @@ EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
// Tell lockdep when RCU callbacks are being invoked.
static struct lock_class_key rcu_callback_key;
-struct lockdep_map rcu_callback_map =
- STATIC_LOCKDEP_MAP_INIT("rcu_callback", &rcu_callback_key);
+struct lockdep_map rcu_callback_map = {
+ .name = "rcu_callback",
+ .key = &rcu_callback_key,
+ .wait_type_outer = LD_WAIT_FREE,
+ .wait_type_inner = LD_WAIT_CONFIG, /* RCU callbacks are handled in softirq context */
+};
EXPORT_SYMBOL_GPL(rcu_callback_map);
noinstr int notrace debug_lockdep_rcu_enabled(void)
--
2.29.2
next prev parent reply other threads:[~2020-12-08 10:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-08 10:31 [RFC lockdep 0/4] Fixes and self testcases for wait context detection Boqun Feng
2020-12-08 10:31 ` [RFC lockdep 1/4] lockdep/selftest: Make HARDIRQ context threaded Boqun Feng
2020-12-08 10:31 ` [RFC lockdep 2/4] lockdep: Allow wait context checking with empty ->held_locks Boqun Feng
2020-12-08 10:31 ` Boqun Feng [this message]
2020-12-08 10:31 ` [RFC lockdep 4/4] lockdep/selftest: Add wait context selftests Boqun Feng
2020-12-08 14:33 ` Peter Zijlstra
2020-12-08 15:31 ` Boqun Feng
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