From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
To: linux-kernel@vger.kernel.org
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Bjorn Helgaas <bhelgaas@google.com>,
Borislav Petkov <bp@alien8.de>,
c0d1n61at3@gmail.com, "David S. Miller" <davem@davemloft.net>,
edumazet@google.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Josh Triplett <josh@joshtriplett.org>,
keescook@chromium.org, kernel-hardening@lists.openwall.com,
kernel-team@android.com, Lai Jiangshan <jiangshanlai@gmail.com>,
Len Brown <lenb@kernel.org>,
linux-acpi@vger.kernel.org, linux-doc@vger.kernel.org,
linux-pci@vger.kernel.org, linux-pm@vger.kernel.org,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
neilb@suse.com, netdev@vger.kernel.org,
Oleg Nesterov <oleg@redhat.com>,
"Paul E. McKenney" <paulmck@linux.ibm.com>,
Pavel Machek <pavel@ucw.cz>,
peterz@infradead.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
rcu@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>,
Tejun Heo <tj@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
will@kernel.org,
x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT))
Subject: [PATCH 2/9] rcu: Add support for consolidated-RCU reader checking (v3)
Date: Mon, 15 Jul 2019 10:36:58 -0400 [thread overview]
Message-ID: <20190715143705.117908-3-joel@joelfernandes.org> (raw)
In-Reply-To: <20190715143705.117908-1-joel@joelfernandes.org>
This patch adds support for checking RCU reader sections in list
traversal macros. Optionally, if the list macro is called under SRCU or
other lock/mutex protection, then appropriate lockdep expressions can be
passed to make the checks pass.
Existing list_for_each_entry_rcu() invocations don't need to pass the
optional fourth argument (cond) unless they are under some non-RCU
protection and needs to make lockdep check pass.
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
include/linux/rculist.h | 28 ++++++++++++++++++++-----
include/linux/rcupdate.h | 7 +++++++
kernel/rcu/Kconfig.debug | 11 ++++++++++
kernel/rcu/update.c | 44 ++++++++++++++++++++++++----------------
4 files changed, 67 insertions(+), 23 deletions(-)
diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index e91ec9ddcd30..1048160625bb 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -40,6 +40,20 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list)
*/
#define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next)))
+/*
+ * Check during list traversal that we are within an RCU reader
+ */
+
+#ifdef CONFIG_PROVE_RCU_LIST
+#define __list_check_rcu(dummy, cond, ...) \
+ ({ \
+ RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \
+ "RCU-list traversed in non-reader section!"); \
+ })
+#else
+#define __list_check_rcu(dummy, cond, ...) ({})
+#endif
+
/*
* Insert a new entry between two known consecutive entries.
*
@@ -343,14 +357,16 @@ static inline void list_splice_tail_init_rcu(struct list_head *list,
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_head within the struct.
+ * @cond: optional lockdep expression if called from non-RCU protection.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as list_add_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
-#define list_for_each_entry_rcu(pos, head, member) \
- for (pos = list_entry_rcu((head)->next, typeof(*pos), member); \
- &pos->member != (head); \
+#define list_for_each_entry_rcu(pos, head, member, cond...) \
+ for (__list_check_rcu(dummy, ## cond, 0), \
+ pos = list_entry_rcu((head)->next, typeof(*pos), member); \
+ &pos->member != (head); \
pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
/**
@@ -616,13 +632,15 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n,
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
+ * @cond: optional lockdep expression if called from non-RCU protection.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as hlist_add_head_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
-#define hlist_for_each_entry_rcu(pos, head, member) \
- for (pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\
+#define hlist_for_each_entry_rcu(pos, head, member, cond...) \
+ for (__list_check_rcu(dummy, ## cond, 0), \
+ pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\
typeof(*(pos)), member); \
pos; \
pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 8f7167478c1d..f3c29efdf19a 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -221,6 +221,7 @@ int debug_lockdep_rcu_enabled(void);
int rcu_read_lock_held(void);
int rcu_read_lock_bh_held(void);
int rcu_read_lock_sched_held(void);
+int rcu_read_lock_any_held(void);
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
@@ -241,6 +242,12 @@ static inline int rcu_read_lock_sched_held(void)
{
return !preemptible();
}
+
+static inline int rcu_read_lock_any_held(void)
+{
+ return !preemptible();
+}
+
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
#ifdef CONFIG_PROVE_RCU
diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
index 5ec3ea4028e2..7fbd21dbfcd0 100644
--- a/kernel/rcu/Kconfig.debug
+++ b/kernel/rcu/Kconfig.debug
@@ -8,6 +8,17 @@ menu "RCU Debugging"
config PROVE_RCU
def_bool PROVE_LOCKING
+config PROVE_RCU_LIST
+ bool "RCU list lockdep debugging"
+ depends on PROVE_RCU
+ default n
+ help
+ Enable RCU lockdep checking for list usages. By default it is
+ turned off since there are several list RCU users that still
+ need to be converted to pass a lockdep expression. To prevent
+ false-positive splats, we keep it default disabled but once all
+ users are converted, we can remove this config option.
+
config TORTURE_TEST
tristate
default n
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 9dd5aeef6e70..b7a4e3b5fa98 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -91,14 +91,18 @@ module_param(rcu_normal_after_boot, int, 0);
* Similarly, we avoid claiming an SRCU read lock held if the current
* CPU is offline.
*/
+#define rcu_read_lock_held_common() \
+ if (!debug_lockdep_rcu_enabled()) \
+ return 1; \
+ if (!rcu_is_watching()) \
+ return 0; \
+ if (!rcu_lockdep_current_cpu_online()) \
+ return 0;
+
int rcu_read_lock_sched_held(void)
{
- if (!debug_lockdep_rcu_enabled())
- return 1;
- if (!rcu_is_watching())
- return 0;
- if (!rcu_lockdep_current_cpu_online())
- return 0;
+ rcu_read_lock_held_common();
+
return lock_is_held(&rcu_sched_lock_map) || !preemptible();
}
EXPORT_SYMBOL(rcu_read_lock_sched_held);
@@ -257,12 +261,8 @@ NOKPROBE_SYMBOL(debug_lockdep_rcu_enabled);
*/
int rcu_read_lock_held(void)
{
- if (!debug_lockdep_rcu_enabled())
- return 1;
- if (!rcu_is_watching())
- return 0;
- if (!rcu_lockdep_current_cpu_online())
- return 0;
+ rcu_read_lock_held_common();
+
return lock_is_held(&rcu_lock_map);
}
EXPORT_SYMBOL_GPL(rcu_read_lock_held);
@@ -284,16 +284,24 @@ EXPORT_SYMBOL_GPL(rcu_read_lock_held);
*/
int rcu_read_lock_bh_held(void)
{
- if (!debug_lockdep_rcu_enabled())
- return 1;
- if (!rcu_is_watching())
- return 0;
- if (!rcu_lockdep_current_cpu_online())
- return 0;
+ rcu_read_lock_held_common();
+
return in_softirq() || irqs_disabled();
}
EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
+int rcu_read_lock_any_held(void)
+{
+ rcu_read_lock_held_common();
+
+ if (lock_is_held(&rcu_lock_map) ||
+ lock_is_held(&rcu_bh_lock_map) ||
+ lock_is_held(&rcu_sched_lock_map))
+ return 1;
+ return !preemptible();
+}
+EXPORT_SYMBOL_GPL(rcu_read_lock_any_held);
+
#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
/**
--
2.22.0.510.g264f2c817a-goog
next prev parent reply other threads:[~2019-07-15 14:45 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 14:36 [PATCH 0/9] Harden list_for_each_entry_rcu() and family Joel Fernandes (Google)
2019-07-15 14:36 ` [PATCH 1/9] rcu/update: Remove useless check for debug_locks (v1) Joel Fernandes (Google)
2019-07-15 14:36 ` Joel Fernandes (Google) [this message]
2019-07-16 18:38 ` [PATCH 2/9] rcu: Add support for consolidated-RCU reader checking (v3) Paul E. McKenney
2019-07-16 18:46 ` Joel Fernandes
2019-07-16 18:53 ` Paul E. McKenney
2019-07-16 22:02 ` Joel Fernandes
2019-07-17 0:07 ` Paul E. McKenney
2019-07-15 14:36 ` [PATCH 3/9] rcu/sync: Remove custom check for reader-section (v2) Joel Fernandes (Google)
2019-07-16 18:39 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 4/9] ipv4: add lockdep condition to fix for_each_entry (v1) Joel Fernandes (Google)
2019-07-16 18:39 ` Paul E. McKenney
2019-07-16 21:12 ` David Miller
2019-07-15 14:37 ` [PATCH 5/9] driver/core: Convert to use built-in RCU list checking (v1) Joel Fernandes (Google)
2019-07-16 18:40 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 6/9] workqueue: Convert for_each_wq to use built-in list check (v2) Joel Fernandes (Google)
2019-07-16 18:41 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 7/9] x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator (v1) Joel Fernandes (Google)
2019-07-15 20:02 ` Bjorn Helgaas
2019-07-16 4:03 ` Joel Fernandes
2019-07-16 18:42 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 8/9] acpi: Use built-in RCU list checking for acpi_ioremaps list (v1) Joel Fernandes (Google)
2019-07-15 21:44 ` Rafael J. Wysocki
2019-07-16 18:43 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 9/9] doc: Update documentation about list_for_each_entry_rcu (v1) Joel Fernandes (Google)
2019-07-16 18:46 ` [PATCH 0/9] Harden list_for_each_entry_rcu() and family Paul E. McKenney
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