diff mbox series

locking/lockdep: Move mark_lock() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING

Message ID 20190617124718.1232976-1-arnd@arndb.de
State Accepted
Commit 886532aee3cd42d95196601ed16d7c3d4679e9e5
Headers show
Series locking/lockdep: Move mark_lock() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING | expand

Commit Message

Arnd Bergmann June 17, 2019, 12:47 p.m. UTC 
The last cleanup patch triggered another issue, as now another function
should be moved into the same section:

kernel/locking/lockdep.c:3580:12: error: 'mark_lock' defined but not used [-Werror=unused-function]
 static int mark_lock(struct task_struct *curr, struct held_lock *this,

Move mark_lock() into the same #ifdef section as its only caller, and
remove the now-unused mark_lock_irq() stub helper.

Fixes: 0d2cc3b34532 ("locking/lockdep: Move valid_state() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
 kernel/locking/lockdep.c | 73 +++++++++++++++++++---------------------
 1 file changed, 34 insertions(+), 39 deletions(-)

-- 
2.20.0

Comments

Will Deacon June 24, 2019, 12:17 p.m. UTC | #1 
Hi Arnd,

On Mon, Jun 17, 2019 at 02:47:05PM +0200, Arnd Bergmann wrote:
> The last cleanup patch triggered another issue, as now another function

> should be moved into the same section:

> 

> kernel/locking/lockdep.c:3580:12: error: 'mark_lock' defined but not used [-Werror=unused-function]

>  static int mark_lock(struct task_struct *curr, struct held_lock *this,

> 

> Move mark_lock() into the same #ifdef section as its only caller, and

> remove the now-unused mark_lock_irq() stub helper.

> 

> Fixes: 0d2cc3b34532 ("locking/lockdep: Move valid_state() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING")

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

> ---

>  kernel/locking/lockdep.c | 73 +++++++++++++++++++---------------------

>  1 file changed, 34 insertions(+), 39 deletions(-)

> 

> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c

> index 48a840adb281..43e880ceafc2 100644

> --- a/kernel/locking/lockdep.c

> +++ b/kernel/locking/lockdep.c

> @@ -437,13 +437,6 @@ static int verbose(struct lock_class *class)

>  	return 0;

>  }

>  

> -/*

> - * Stack-trace: tightly packed array of stack backtrace

> - * addresses. Protected by the graph_lock.

> - */

> -unsigned long nr_stack_trace_entries;

> -static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];

> -

>  static void print_lockdep_off(const char *bug_msg)

>  {

>  	printk(KERN_DEBUG "%s\n", bug_msg);

> @@ -453,6 +446,15 @@ static void print_lockdep_off(const char *bug_msg)

>  #endif

>  }

>  

> +unsigned long nr_stack_trace_entries;

> +

> +#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)


Is this necessary, given that CONFIG_PROVE_LOCKING selects TRACE_IRQFLAGS?
I find that having both of the symbols makes this really hard to read. For
example:

> +/*

> + * Stack-trace: tightly packed array of stack backtrace

> + * addresses. Protected by the graph_lock.

> + */

> +static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];


This is used later on by print_lock_trace(), which is only predicated
on #ifdef CONFIG_PROVE_LOCKING.

Will
Arnd Bergmann June 24, 2019, 4:07 p.m. UTC | #2 
On Mon, Jun 24, 2019 at 2:18 PM Will Deacon <will@kernel.org> wrote:
> On Mon, Jun 17, 2019 at 02:47:05PM +0200, Arnd Bergmann wrote:


> >

> > +unsigned long nr_stack_trace_entries;

> > +

> > +#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)

>

> Is this necessary, given that CONFIG_PROVE_LOCKING selects TRACE_IRQFLAGS?

> I find that having both of the symbols makes this really hard to read.


Probably not. I have removed the CONFIG_TRACE_IRQFLAGS check from
all instances in this file now, and will give it some more testing.

It took me a few iterations to get to a version of this patch that had no
build failures, so I'm a bit careful. I had copied the #if check from what
protected some of the callers. If the change below works, I'll fold it
into my patch and send it again.

       Arnd

--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -448,7 +448,7 @@ static void print_lockdep_off(const char *bug_msg)

 unsigned long nr_stack_trace_entries;

-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+#ifdef CONFIG_PROVE_LOCKING
 /*
  * Stack-trace: tightly packed array of stack backtrace
  * addresses. Protected by the graph_lock.
@@ -491,7 +491,7 @@ unsigned int max_lockdep_depth;
 DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
 #endif

-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+#ifdef CONFIG_PROVE_LOCKING
 /*
  * Locking printouts:
  */
@@ -2969,7 +2969,7 @@ static void check_chain_key(struct task_struct *curr)
 #endif
 }

-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+#ifdef CONFIG_PROVE_LOCKING
 static int mark_lock(struct task_struct *curr, struct held_lock *this,
                     enum lock_usage_bit new_bit);

@@ -3608,7 +3608,7 @@ static int mark_lock(struct task_struct *curr,
struct held_lock *this,
        return ret;
 }

-#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+#else /* CONFIG_PROVE_LOCKING */

 static inline int
 mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
@@ -3627,7 +3627,7 @@ static inline int separate_irq_context(struct
task_struct *curr,
        return 0;
 }

-#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+#endif /* CONFIG_PROVE_LOCKING */

 /*
  * Initialize a lock instance's lock-class mapping info:
@@ -4321,8 +4321,7 @@ static void __lock_unpin_lock(struct lockdep_map
*lock, struct pin_cookie cookie
  */
 static void check_flags(unsigned long flags)
 {
-#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
-    defined(CONFIG_TRACE_IRQFLAGS)
+#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP)
        if (!debug_locks)
                return;
Will Deacon June 25, 2019, 12:16 p.m. UTC | #3 
On Tue, Jun 25, 2019 at 01:46:07AM -0700, tip-bot for Arnd Bergmann wrote:
> Commit-ID:  886532aee3cd42d95196601ed16d7c3d4679e9e5

> Gitweb:     https://git.kernel.org/tip/886532aee3cd42d95196601ed16d7c3d4679e9e5

> Author:     Arnd Bergmann <arnd@arndb.de>

> AuthorDate: Mon, 17 Jun 2019 14:47:05 +0200

> Committer:  Ingo Molnar <mingo@kernel.org>

> CommitDate: Tue, 25 Jun 2019 10:17:07 +0200

> 

> locking/lockdep: Move mark_lock() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING

> 

> The last cleanup patch triggered another issue, as now another function

> should be moved into the same section:

> 

>  kernel/locking/lockdep.c:3580:12: error: 'mark_lock' defined but not used [-Werror=unused-function]

>   static int mark_lock(struct task_struct *curr, struct held_lock *this,

> 

> Move mark_lock() into the same #ifdef section as its only caller, and

> remove the now-unused mark_lock_irq() stub helper.

> 

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

> Cc: Andrew Morton <akpm@linux-foundation.org>

> Cc: Bart Van Assche <bvanassche@acm.org>

> Cc: Frederic Weisbecker <frederic@kernel.org>

> Cc: Linus Torvalds <torvalds@linux-foundation.org>

> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

> Cc: Peter Zijlstra <peterz@infradead.org>

> Cc: Thomas Gleixner <tglx@linutronix.de>

> Cc: Waiman Long <longman@redhat.com>

> Cc: Will Deacon <will.deacon@arm.com>

> Cc: Yuyang Du <duyuyang@gmail.com>

> Fixes: 0d2cc3b34532 ("locking/lockdep: Move valid_state() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING")

> Link: https://lkml.kernel.org/r/20190617124718.1232976-1-arnd@arndb.de

> Signed-off-by: Ingo Molnar <mingo@kernel.org>

> ---

>  kernel/locking/lockdep.c | 73 ++++++++++++++++++++++--------------------------

>  1 file changed, 34 insertions(+), 39 deletions(-)


Hmm, I was hoping we could fold in the simplification that Arnd came up with
yesterday:

https://lkml.kernel.org/r/CAK8P3a2X_5p9QOKG-jcozR4P8iPNJAY2ObXgfqt=bBD+hZdnSg@mail.gmail.com

Will
diff mbox series

Patch

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 48a840adb281..43e880ceafc2 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -437,13 +437,6 @@  static int verbose(struct lock_class *class)
 	return 0;
 }
 
-/*
- * Stack-trace: tightly packed array of stack backtrace
- * addresses. Protected by the graph_lock.
- */
-unsigned long nr_stack_trace_entries;
-static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
-
 static void print_lockdep_off(const char *bug_msg)
 {
 	printk(KERN_DEBUG "%s\n", bug_msg);
@@ -453,6 +446,15 @@  static void print_lockdep_off(const char *bug_msg)
 #endif
 }
 
+unsigned long nr_stack_trace_entries;
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+/*
+ * Stack-trace: tightly packed array of stack backtrace
+ * addresses. Protected by the graph_lock.
+ */
+static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
+
 static int save_trace(struct lock_trace *trace)
 {
 	unsigned long *entries = stack_trace + nr_stack_trace_entries;
@@ -475,6 +477,7 @@  static int save_trace(struct lock_trace *trace)
 
 	return 1;
 }
+#endif
 
 unsigned int nr_hardirq_chains;
 unsigned int nr_softirq_chains;
@@ -488,6 +491,7 @@  unsigned int max_lockdep_depth;
 DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
 #endif
 
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
 /*
  * Locking printouts:
  */
@@ -505,6 +509,7 @@  static const char *usage_str[] =
 #undef LOCKDEP_STATE
 	[LOCK_USED] = "INITIAL USE",
 };
+#endif
 
 const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
 {
@@ -2964,12 +2969,10 @@  static void check_chain_key(struct task_struct *curr)
 #endif
 }
 
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
 static int mark_lock(struct task_struct *curr, struct held_lock *this,
 		     enum lock_usage_bit new_bit);
 
-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
-
-
 static void print_usage_bug_scenario(struct held_lock *lock)
 {
 	struct lock_class *class = hlock_class(lock);
@@ -3545,35 +3548,6 @@  static int separate_irq_context(struct task_struct *curr,
 	return 0;
 }
 
-#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
-
-static inline
-int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
-		enum lock_usage_bit new_bit)
-{
-	WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */
-	return 1;
-}
-
-static inline int
-mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
-{
-	return 1;
-}
-
-static inline unsigned int task_irq_context(struct task_struct *task)
-{
-	return 0;
-}
-
-static inline int separate_irq_context(struct task_struct *curr,
-		struct held_lock *hlock)
-{
-	return 0;
-}
-
-#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
-
 /*
  * Mark a lock with a usage bit, and validate the state transition:
  */
@@ -3634,6 +3608,27 @@  static int mark_lock(struct task_struct *curr, struct held_lock *this,
 	return ret;
 }
 
+#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+
+static inline int
+mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
+{
+	return 1;
+}
+
+static inline unsigned int task_irq_context(struct task_struct *task)
+{
+	return 0;
+}
+
+static inline int separate_irq_context(struct task_struct *curr,
+		struct held_lock *hlock)
+{
+	return 0;
+}
+
+#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+
 /*
  * Initialize a lock instance's lock-class mapping info:
  */