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core/printk changes for v3.3

GIT PULL Ingo Molnar 1 participant 1 message Jan 5, 2012 Locking primitives

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Ingo Molnar

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Linus,

Please pull the latest core-printk-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core-printk-for-linus

Thanks,

Ingo

------------------>
Peter Zijlstra (3):
printk, lockdep: Disable lock debugging on zap_locks() printk, lockdep: Remove superfluous preempt_disable() printk, lockdep: Switch to tracked irq ops

 include/linux/lockdep.h |    4 ++++
 kernel/printk.c         |    9 ++++-----
 2 files changed, 8 insertions(+), 5 deletions(-)
include/linux/lockdep.h +4 -0
index b6a56e3..d36619e 100644
@@ -343,6 +343,8 @@ extern void lockdep_trace_alloc(gfp_t mask);
 
 #define lockdep_assert_held(l)	WARN_ON(debug_locks && !lockdep_is_held(l))
 
+#define lockdep_recursing(tsk)	((tsk)->lockdep_recursion)
+
 #else /* !LOCKDEP */
 
 static inline void lockdep_off(void)

@@ -392,6 +394,8 @@ struct lock_class_key { };
 
 #define lockdep_assert_held(l)			do { } while (0)
 
+#define lockdep_recursing(tsk)			(0)
+
 #endif /* !LOCKDEP */
 
 #ifdef CONFIG_LOCK_STAT
kernel/printk.c +4 -5
index 1455a0d..dfd8f73 100644
@@ -688,6 +688,7 @@ static void zap_locks(void)
 
 	oops_timestamp = jiffies;
 
+	debug_locks_off();
 	/* If a crash is occurring, make sure we can't deadlock */
 	raw_spin_lock_init(&logbuf_lock);
 	/* And make sure that we print immediately */

@@ -840,9 +841,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 	boot_delay_msec();
 	printk_delay();
 
-	preempt_disable();
 	/* This stops the holder of console_sem just where we want him */
-	raw_local_irq_save(flags);
+	local_irq_save(flags);
 	this_cpu = smp_processor_id();
 
 	/*

@@ -856,7 +856,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 		 * recursion and return - but flag the recursion so that
 		 * it can be printed at the next appropriate moment:
 		 */
-		if (!oops_in_progress) {
+		if (!oops_in_progress && !lockdep_recursing(current)) {
 			recursion_bug = 1;
 			goto out_restore_irqs;
 		}

@@ -962,9 +962,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 
 	lockdep_on();
 out_restore_irqs:
-	raw_local_irq_restore(flags);
+	local_irq_restore(flags);
 
-	preempt_enable();
 	return printed_len;
 }
 EXPORT_SYMBOL(printk);