Message-ID: <20150618225420.GQ3913@linux.vnet.ibm.com>
Date:	Thu, 18 Jun 2015 15:54:20 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Andy Lutomirski <luto@...nel.org>, x86@...nel.org,
	linux-kernel@...r.kernel.org,
	Frédéric Weisbecker <fweisbec@...il.com>,
	Rik van Riel <riel@...hat.com>,
	Oleg Nesterov <oleg@...hat.com>,
	Denys Vlasenko <vda.linux@...glemail.com>,
	Borislav Petkov <bp@...en8.de>,
	Kees Cook <keescook@...omium.org>,
	Brian Gerst <brgerst@...il.com>
Subject: Re: [RFC/INCOMPLETE 01/13] context_tracking: Add
 context_tracking_assert_state

On Thu, Jun 18, 2015 at 11:59:55AM +0200, Ingo Molnar wrote:
> 
> * Paul E. McKenney <paulmck@...ux.vnet.ibm.com> wrote:
> 
> > On Wed, Jun 17, 2015 at 11:41:14AM +0200, Ingo Molnar wrote:
> > > 
> > > * Andy Lutomirski <luto@...nel.org> wrote:
> > > 
> > > > This will let us sprinkle sanity checks around the kernel without
> > > > making too much of a mess.
> > > > 
> > > > Signed-off-by: Andy Lutomirski <luto@...nel.org>
> > > > ---
> > > >  include/linux/context_tracking.h | 8 ++++++++
> > > >  1 file changed, 8 insertions(+)
> > > > 
> > > > diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
> > > > index 2821838256b4..0fbea4b152e1 100644
> > > > --- a/include/linux/context_tracking.h
> > > > +++ b/include/linux/context_tracking.h
> > > > @@ -57,6 +57,13 @@ static inline void context_tracking_task_switch(struct task_struct *prev,
> > > >  	if (context_tracking_is_enabled())
> > > >  		__context_tracking_task_switch(prev, next);
> > > >  }
> > > > +
> > > > +static inline void context_tracking_assert_state(enum ctx_state state)
> > > > +{
> > > > +	rcu_lockdep_assert(!context_tracking_is_enabled() ||
> > > > +			   this_cpu_read(context_tracking.state) == state,
> > > > +			   "context tracking state was wrong");
> > > > +}
> > > 
> > > Please don't introduce assert() style debug check interfaces!
> > > 
> > > (And RCU should be fixed too I suspect.)
> > 
> > The thought is to rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN()
> > by analogy to WARN()?  Easy to do if so!  Or am I missing the point?
> 
> Yeah, and inverting the condition. Assuming the condition was assert()-style 
> inverted to begin with! :-)

It appears to have been.  ;-)

Please see below for an untested patch.  I made this be one big patch,
but could have one patch add RCU_LOCKDEP_WARN(), a series convert uses
from rcu_lockdep_assert() to RCU_LOCKDEP_WARN(), and a final patch
remove rcu_lockdep_assert().  Let me know!

> and lockdep should be fixed too I suspect, lockdep_assert_held() was really a 
> poorly chosen name I suspect, it should be 'lockdep_check_held()' or so? It has 
> very little to do with the assert() interface.

------------------------------------------------------------------------

commit a3053da26e914ab9d7fe25b03d35bbe5a2a718c0
Author: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Date:   Thu Jun 18 15:50:02 2015 -0700

    rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN()
    
    This commit renames rcu_lockdep_assert() to RCU_LOCKDEP_WARN() for
    consistency with the WARN() series of macros.  This also requires
    inverting the sense of the conditional, which this commit also does.
    
    Reported-by: Ingo Molnar <mingo@...nel.org>
    Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 324ab5247687..37f827cb78ed 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -136,7 +136,7 @@ enum ctx_state ist_enter(struct pt_regs *regs)
 	preempt_count_add(HARDIRQ_OFFSET);
 
 	/* This code is a bit fragile.  Test it. */
-	rcu_lockdep_assert(rcu_is_watching(), "ist_enter didn't work");
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "ist_enter didn't work");
 
 	return prev_state;
 }
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 677fb2843553..3b188f20b43f 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -110,8 +110,8 @@ static DEFINE_MUTEX(dev_opp_list_lock);
 
 #define opp_rcu_lockdep_assert()					\
 do {									\
-	rcu_lockdep_assert(rcu_read_lock_held() ||			\
-				lockdep_is_held(&dev_opp_list_lock),	\
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
+				!lockdep_is_held(&dev_opp_list_lock),	\
 			   "Missing rcu_read_lock() or "		\
 			   "dev_opp_list_lock protection");		\
 } while (0)
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index 230f87bdf5ad..910c75f6cd0b 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -83,8 +83,8 @@ static inline struct file *__fcheck_files(struct files_struct *files, unsigned i
 
 static inline struct file *fcheck_files(struct files_struct *files, unsigned int fd)
 {
-	rcu_lockdep_assert(rcu_read_lock_held() ||
-			   lockdep_is_held(&files->file_lock),
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
+			   !lockdep_is_held(&files->file_lock),
 			   "suspicious rcu_dereference_check() usage");
 	return __fcheck_files(files, fd);
 }
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 2f4a93a8ceab..e9e04c32cb4c 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -537,14 +537,14 @@ static inline int rcu_read_lock_sched_held(void)
 #ifdef CONFIG_PROVE_RCU
 
 /**
- * rcu_lockdep_assert - emit lockdep splat if specified condition not met
+ * RCU_LOCKDEP_WARN - emit lockdep splat if specified condition is met
  * @c: condition to check
  * @s: informative message
  */
-#define rcu_lockdep_assert(c, s)					\
+#define RCU_LOCKDEP_WARN(c, s)						\
 	do {								\
 		static bool __section(.data.unlikely) __warned;		\
-		if (debug_lockdep_rcu_enabled() && !__warned && !(c)) {	\
+		if (debug_lockdep_rcu_enabled() && !__warned && (c)) {	\
 			__warned = true;				\
 			lockdep_rcu_suspicious(__FILE__, __LINE__, s);	\
 		}							\
@@ -553,8 +553,8 @@ static inline int rcu_read_lock_sched_held(void)
 #if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_PREEMPT_RCU)
 static inline void rcu_preempt_sleep_check(void)
 {
-	rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
-			   "Illegal context switch in RCU read-side critical section");
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_lock_map),
+			 "Illegal context switch in RCU read-side critical section");
 }
 #else /* #ifdef CONFIG_PROVE_RCU */
 static inline void rcu_preempt_sleep_check(void)
@@ -565,15 +565,15 @@ static inline void rcu_preempt_sleep_check(void)
 #define rcu_sleep_check()						\
 	do {								\
 		rcu_preempt_sleep_check();				\
-		rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map),	\
-				   "Illegal context switch in RCU-bh read-side critical section"); \
-		rcu_lockdep_assert(!lock_is_held(&rcu_sched_lock_map),	\
-				   "Illegal context switch in RCU-sched read-side critical section"); \
+		RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map),	\
+				 "Illegal context switch in RCU-bh read-side critical section"); \
+		RCU_LOCKDEP_WARN(lock_is_held(&rcu_sched_lock_map),	\
+				 "Illegal context switch in RCU-sched read-side critical section"); \
 	} while (0)
 
 #else /* #ifdef CONFIG_PROVE_RCU */
 
-#define rcu_lockdep_assert(c, s) do { } while (0)
+#define RCU_LOCKDEP_WARN(c, s) do { } while (0)
 #define rcu_sleep_check() do { } while (0)
 
 #endif /* #else #ifdef CONFIG_PROVE_RCU */
@@ -604,13 +604,13 @@ static inline void rcu_preempt_sleep_check(void)
 ({ \
 	/* Dependency order vs. p above. */ \
 	typeof(*p) *________p1 = (typeof(*p) *__force)lockless_dereference(p); \
-	rcu_lockdep_assert(c, "suspicious rcu_dereference_check() usage"); \
+	RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_check() usage"); \
 	rcu_dereference_sparse(p, space); \
 	((typeof(*p) __force __kernel *)(________p1)); \
 })
 #define __rcu_dereference_protected(p, c, space) \
 ({ \
-	rcu_lockdep_assert(c, "suspicious rcu_dereference_protected() usage"); \
+	RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_protected() usage"); \
 	rcu_dereference_sparse(p, space); \
 	((typeof(*p) __force __kernel *)(p)); \
 })
@@ -849,8 +849,8 @@ static inline void rcu_read_lock(void)
 	__rcu_read_lock();
 	__acquire(RCU);
 	rcu_lock_acquire(&rcu_lock_map);
-	rcu_lockdep_assert(rcu_is_watching(),
-			   "rcu_read_lock() used illegally while idle");
+	RCU_LOCKDEP_WARN(!rcu_is_watching(),
+			 "rcu_read_lock() used illegally while idle");
 }
 
 /*
@@ -900,8 +900,8 @@ static inline void rcu_read_lock(void)
  */
 static inline void rcu_read_unlock(void)
 {
-	rcu_lockdep_assert(rcu_is_watching(),
-			   "rcu_read_unlock() used illegally while idle");
+	RCU_LOCKDEP_WARN(!rcu_is_watching(),
+			 "rcu_read_unlock() used illegally while idle");
 	__release(RCU);
 	__rcu_read_unlock();
 	rcu_lock_release(&rcu_lock_map); /* Keep acq info for rls diags. */
@@ -929,8 +929,8 @@ static inline void rcu_read_lock_bh(void)
 	local_bh_disable();
 	__acquire(RCU_BH);
 	rcu_lock_acquire(&rcu_bh_lock_map);
-	rcu_lockdep_assert(rcu_is_watching(),
-			   "rcu_read_lock_bh() used illegally while idle");
+	RCU_LOCKDEP_WARN(!rcu_is_watching(),
+			 "rcu_read_lock_bh() used illegally while idle");
 }
 
 /*
@@ -940,8 +940,8 @@ static inline void rcu_read_lock_bh(void)
  */
 static inline void rcu_read_unlock_bh(void)
 {
-	rcu_lockdep_assert(rcu_is_watching(),
-			   "rcu_read_unlock_bh() used illegally while idle");
+	RCU_LOCKDEP_WARN(!rcu_is_watching(),
+			 "rcu_read_unlock_bh() used illegally while idle");
 	rcu_lock_release(&rcu_bh_lock_map);
 	__release(RCU_BH);
 	local_bh_enable();
@@ -965,8 +965,8 @@ static inline void rcu_read_lock_sched(void)
 	preempt_disable();
 	__acquire(RCU_SCHED);
 	rcu_lock_acquire(&rcu_sched_lock_map);
-	rcu_lockdep_assert(rcu_is_watching(),
-			   "rcu_read_lock_sched() used illegally while idle");
+	RCU_LOCKDEP_WARN(!rcu_is_watching(),
+			 "rcu_read_lock_sched() used illegally while idle");
 }
 
 /* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
@@ -983,8 +983,8 @@ static inline notrace void rcu_read_lock_sched_notrace(void)
  */
 static inline void rcu_read_unlock_sched(void)
 {
-	rcu_lockdep_assert(rcu_is_watching(),
-			   "rcu_read_unlock_sched() used illegally while idle");
+	RCU_LOCKDEP_WARN(!rcu_is_watching(),
+			 "rcu_read_unlock_sched() used illegally while idle");
 	rcu_lock_release(&rcu_sched_lock_map);
 	__release(RCU_SCHED);
 	preempt_enable();
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 469dd547770c..ad2d0162532a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -104,8 +104,8 @@ static DEFINE_SPINLOCK(cgroup_idr_lock);
 static DEFINE_SPINLOCK(release_agent_path_lock);
 
 #define cgroup_assert_mutex_or_rcu_locked()				\
-	rcu_lockdep_assert(rcu_read_lock_held() ||			\
-			   lockdep_is_held(&cgroup_mutex),		\
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
+			   !lockdep_is_held(&cgroup_mutex),		\
 			   "cgroup_mutex or RCU read lock required");
 
 /*
diff --git a/kernel/pid.c b/kernel/pid.c
index 4fd07d5b7baf..ca368793808e 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -451,9 +451,8 @@ EXPORT_SYMBOL(pid_task);
  */
 struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns)
 {
-	rcu_lockdep_assert(rcu_read_lock_held(),
-			   "find_task_by_pid_ns() needs rcu_read_lock()"
-			   " protection");
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
+			 "find_task_by_pid_ns() needs rcu_read_lock() protection");
 	return pid_task(find_pid_ns(nr, ns), PIDTYPE_PID);
 }
 
diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c
index de35087c92a5..d3fcb2ec8536 100644
--- a/kernel/rcu/srcu.c
+++ b/kernel/rcu/srcu.c
@@ -415,11 +415,11 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount)
 	struct rcu_head *head = &rcu.head;
 	bool done = false;
 
-	rcu_lockdep_assert(!lock_is_held(&sp->dep_map) &&
-			   !lock_is_held(&rcu_bh_lock_map) &&
-			   !lock_is_held(&rcu_lock_map) &&
-			   !lock_is_held(&rcu_sched_lock_map),
-			   "Illegal synchronize_srcu() in same-type SRCU (or RCU) read-side critical section");
+	RCU_LOCKDEP_WARN(lock_is_held(&sp->dep_map) ||
+			 lock_is_held(&rcu_bh_lock_map) ||
+			 lock_is_held(&rcu_lock_map) ||
+			 lock_is_held(&rcu_sched_lock_map),
+			 "Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section");
 
 	might_sleep();
 	init_completion(&rcu.completion);
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index 591af0cb7b9f..e888602d5c56 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -191,10 +191,10 @@ static void rcu_process_callbacks(struct softirq_action *unused)
  */
 void synchronize_sched(void)
 {
-	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&
-			   !lock_is_held(&rcu_lock_map) &&
-			   !lock_is_held(&rcu_sched_lock_map),
-			   "Illegal synchronize_sched() in RCU read-side critical section");
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+			 lock_is_held(&rcu_lock_map) ||
+			 lock_is_held(&rcu_sched_lock_map),
+			 "Illegal synchronize_sched() in RCU read-side critical section");
 	cond_resched();
 }
 EXPORT_SYMBOL_GPL(synchronize_sched);
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index c844ef3c2fae..78d0a87ff354 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -644,12 +644,12 @@ static void rcu_eqs_enter_common(long long oldval, bool user)
 	 * It is illegal to enter an extended quiescent state while
 	 * in an RCU read-side critical section.
 	 */
-	rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
-			   "Illegal idle entry in RCU read-side critical section.");
-	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map),
-			   "Illegal idle entry in RCU-bh read-side critical section.");
-	rcu_lockdep_assert(!lock_is_held(&rcu_sched_lock_map),
-			   "Illegal idle entry in RCU-sched read-side critical section.");
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_lock_map),
+			 "Illegal idle entry in RCU read-side critical section.");
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map),
+			 "Illegal idle entry in RCU-bh read-side critical section.");
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_sched_lock_map),
+			 "Illegal idle entry in RCU-sched read-side critical section.");
 }
 
 /*
@@ -3162,10 +3162,10 @@ static inline int rcu_blocking_is_gp(void)
  */
 void synchronize_sched(void)
 {
-	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&
-			   !lock_is_held(&rcu_lock_map) &&
-			   !lock_is_held(&rcu_sched_lock_map),
-			   "Illegal synchronize_sched() in RCU-sched read-side critical section");
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+			 lock_is_held(&rcu_lock_map) ||
+			 lock_is_held(&rcu_sched_lock_map),
+			 "Illegal synchronize_sched() in RCU-sched read-side critical section");
 	if (rcu_blocking_is_gp())
 		return;
 	if (rcu_gp_is_expedited())
@@ -3189,10 +3189,10 @@ EXPORT_SYMBOL_GPL(synchronize_sched);
  */
 void synchronize_rcu_bh(void)
 {
-	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&
-			   !lock_is_held(&rcu_lock_map) &&
-			   !lock_is_held(&rcu_sched_lock_map),
-			   "Illegal synchronize_rcu_bh() in RCU-bh read-side critical section");
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+			 lock_is_held(&rcu_lock_map) ||
+			 lock_is_held(&rcu_sched_lock_map),
+			 "Illegal synchronize_rcu_bh() in RCU-bh read-side critical section");
 	if (rcu_blocking_is_gp())
 		return;
 	if (rcu_gp_is_expedited())
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 85addcf7d184..07bd9fb393b4 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -522,10 +522,10 @@ EXPORT_SYMBOL_GPL(call_rcu);
  */
 void synchronize_rcu(void)
 {
-	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&
-			   !lock_is_held(&rcu_lock_map) &&
-			   !lock_is_held(&rcu_sched_lock_map),
-			   "Illegal synchronize_rcu() in RCU read-side critical section");
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+			 lock_is_held(&rcu_lock_map) ||
+			 lock_is_held(&rcu_sched_lock_map),
+			 "Illegal synchronize_rcu() in RCU read-side critical section");
 	if (!rcu_scheduler_active)
 		return;
 	if (rcu_gp_is_expedited())
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index a0a0dd03c73a..47268fb1d27b 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -589,8 +589,8 @@ EXPORT_SYMBOL_GPL(call_rcu_tasks);
 void synchronize_rcu_tasks(void)
 {
 	/* Complain if the scheduler has not started.  */
-	rcu_lockdep_assert(!rcu_scheduler_active,
-			   "synchronize_rcu_tasks called too soon");
+	RCU_LOCKDEP_WARN(rcu_scheduler_active,
+			 "synchronize_rcu_tasks called too soon");
 
 	/* Wait for the grace period. */
 	wait_rcu_gp(call_rcu_tasks);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fe22f7510bce..7956c016e750 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1987,8 +1987,8 @@ unsigned long to_ratio(u64 period, u64 runtime)
 #ifdef CONFIG_SMP
 inline struct dl_bw *dl_bw_of(int i)
 {
-	rcu_lockdep_assert(rcu_read_lock_sched_held(),
-			   "sched RCU must be held");
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
 	return &cpu_rq(i)->rd->dl_bw;
 }
 
@@ -1997,8 +1997,8 @@ static inline int dl_bw_cpus(int i)
 	struct root_domain *rd = cpu_rq(i)->rd;
 	int cpus = 0;
 
-	rcu_lockdep_assert(rcu_read_lock_sched_held(),
-			   "sched RCU must be held");
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
 	for_each_cpu_and(i, rd->span, cpu_active_mask)
 		cpus++;
 
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 586ad91300b0..80bc8dc8d286 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -338,14 +338,14 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
 #include <trace/events/workqueue.h>
 
 #define assert_rcu_or_pool_mutex()					\
-	rcu_lockdep_assert(rcu_read_lock_sched_held() ||		\
-			   lockdep_is_held(&wq_pool_mutex),		\
-			   "sched RCU or wq_pool_mutex should be held")
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() &&			\
+			 !lockdep_is_held(&wq_pool_mutex),		\
+			 "sched RCU or wq_pool_mutex should be held")
 
 #define assert_rcu_or_wq_mutex(wq)					\
-	rcu_lockdep_assert(rcu_read_lock_sched_held() ||		\
-			   lockdep_is_held(&wq->mutex),			\
-			   "sched RCU or wq->mutex should be held")
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() &&			\
+			 !lockdep_is_held(&wq->mutex),			\
+			 "sched RCU or wq->mutex should be held")
 
 #define for_each_cpu_worker_pool(pool, cpu)				\
 	for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0];		\
diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 188c1d26393b..73455089feef 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -400,9 +400,9 @@ static bool verify_new_ex(struct dev_cgroup *dev_cgroup,
 {
 	bool match = false;
 
-	rcu_lockdep_assert(rcu_read_lock_held() ||
-			   lockdep_is_held(&devcgroup_mutex),
-			   "device_cgroup:verify_new_ex called without proper synchronization");
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
+			 lockdep_is_held(&devcgroup_mutex),
+			 "device_cgroup:verify_new_ex called without proper synchronization");
 
 	if (dev_cgroup->behavior == DEVCG_DEFAULT_ALLOW) {
 		if (behavior == DEVCG_DEFAULT_ALLOW) {

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