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>,
"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>,
Josh Triplett <josh@joshtriplett.org>,
keescook@chromium.org, kernel-hardening@lists.openwall.com,
Lai Jiangshan <jiangshanlai@gmail.com>,
Len Brown <lenb@kernel.org>,
linux-acpi@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@redhat.com,
"Paul E. McKenney" <paulmck@linux.ibm.com>,
Pavel Machek <pavel@ucw.cz>,
peterz@infradead.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
rcu@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>,
Tejun Heo <tj@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT))
Subject: [RFC 1/6] rcu: Add support for consolidated-RCU reader checking
Date: Sat, 1 Jun 2019 18:27:33 -0400 [thread overview]
Message-ID: <20190601222738.6856-2-joel@joelfernandes.org> (raw)
In-Reply-To: <20190601222738.6856-1-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 | 40 ++++++++++++++++++++++++++++++++++++----
include/linux/rcupdate.h | 7 +++++++
kernel/rcu/update.c | 26 ++++++++++++++++++++++++++
3 files changed, 69 insertions(+), 4 deletions(-)
diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index e91ec9ddcd30..b641fdd9f1a2 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -40,6 +40,25 @@ 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
+ */
+#define __list_check_rcu() \
+ RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(), \
+ "RCU-list traversed in non-reader section!")
+
+static inline void __list_check_rcu_cond(int dummy, ...)
+{
+ va_list ap;
+ int cond;
+
+ va_start(ap, dummy);
+ cond = va_arg(ap, int);
+ va_end(ap);
+
+ RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(),
+ "RCU-list traversed in non-reader section!");
+}
/*
* Insert a new entry between two known consecutive entries.
*
@@ -338,6 +357,9 @@ static inline void list_splice_tail_init_rcu(struct list_head *list,
member) : NULL; \
})
+#define SIXTH_ARG(a1, a2, a3, a4, a5, a6, ...) a6
+#define COUNT_VARGS(...) SIXTH_ARG(dummy, ## __VA_ARGS__, 4, 3, 2, 1, 0)
+
/**
* list_for_each_entry_rcu - iterate over rcu list of given type
* @pos: the type * to use as a loop cursor.
@@ -348,9 +370,14 @@ static inline void list_splice_tail_init_rcu(struct list_head *list,
* 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...) \
+ if (COUNT_VARGS(cond) != 0) { \
+ __list_check_rcu_cond(0, ## cond); \
+ } else { \
+ __list_check_rcu(); \
+ } \
+ for (pos = list_entry_rcu((head)->next, typeof(*pos), member); \
+ &pos->member != (head); \
pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
/**
@@ -621,7 +648,12 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n,
* 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) \
+#define hlist_for_each_entry_rcu(pos, head, member, cond...) \
+ if (COUNT_VARGS(cond) != 0) { \
+ __list_check_rcu_cond(0, ## cond); \
+ } else { \
+ __list_check_rcu(); \
+ } \
for (pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\
typeof(*(pos)), member); \
pos; \
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 922bb6848813..712b464ab960 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -223,6 +223,7 @@ 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 */
@@ -243,6 +244,12 @@ 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/update.c b/kernel/rcu/update.c
index c3bf44ba42e5..9cb30006a5e1 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -298,6 +298,32 @@ int rcu_read_lock_bh_held(void)
}
EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
+int rcu_read_lock_any_held(void)
+{
+ int lockdep_opinion = 0;
+
+ if (!debug_lockdep_rcu_enabled())
+ return 1;
+ if (!rcu_is_watching())
+ return 0;
+ if (!rcu_lockdep_current_cpu_online())
+ return 0;
+
+ /* Preemptible RCU flavor */
+ if (lock_is_held(&rcu_lock_map))
+ return 1;
+
+ /* BH flavor */
+ if (in_softirq() || irqs_disabled())
+ return 1;
+
+ /* Sched flavor */
+ if (debug_locks)
+ lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
+ return lockdep_opinion || !preemptible();
+}
+EXPORT_SYMBOL_GPL(rcu_read_lock_any_held);
+
#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
/**
--
2.22.0.rc1.311.g5d7573a151-goog
next prev parent reply other threads:[~2019-06-01 22:27 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-01 22:27 [RFC 0/6] Harden list_for_each_entry_rcu() and family Joel Fernandes (Google)
2019-06-01 22:27 ` Joel Fernandes (Google) [this message]
2019-06-03 8:01 ` [RFC 1/6] rcu: Add support for consolidated-RCU reader checking Peter Zijlstra
2019-06-03 14:18 ` Joel Fernandes
2019-06-03 19:42 ` Joel Fernandes
2019-06-04 10:53 ` Steven Rostedt
2019-06-04 17:48 ` Joel Fernandes
2019-06-04 14:01 ` Rasmus Villemoes
2019-06-04 23:57 ` Joel Fernandes
2019-06-01 22:27 ` [RFC 2/6] ipv4: add lockdep condition to fix for_each_entry Joel Fernandes (Google)
2019-06-02 7:00 ` Pavel Machek
2019-06-02 12:20 ` Joel Fernandes
2019-06-02 12:24 ` Joel Fernandes
2019-06-03 6:42 ` Pavel Machek
2019-06-03 12:28 ` Joel Fernandes
2019-06-01 22:27 ` [RFC 3/6] driver/core: Convert to use built-in RCU list checking Joel Fernandes (Google)
2019-06-01 22:27 ` [RFC 4/6] workqueue: Convert for_each_wq to use built-in list check Joel Fernandes (Google)
2019-06-05 1:24 ` Daniel Jordan
2019-06-05 13:04 ` Joel Fernandes
2019-06-01 22:27 ` [RFC 5/6] x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator Joel Fernandes (Google)
2019-06-01 22:27 ` [RFC 6/6] acpi: Use built-in RCU list checking for acpi_ioremaps list Joel Fernandes (Google)
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