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authorLinus Torvalds <torvalds@linux-foundation.org>2011-07-22 19:43:49 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-07-22 19:43:49 -0400
commit391d6276db9fbdedfbc30e1b56390414f0e55988 (patch)
treed22cd2482f5452d616ee981e954074ffc6ae094d
parent75b56ec294b074d70f8a676ab02611a3fea76cab (diff)
parentdd4e5d3ac4a76b868daf30e35bd572def96c30ed (diff)
Merge branch 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: lockdep: Fix trace_[soft,hard]irqs_[on,off]() recursion printk: Fix console_sem vs logbuf_lock unlock race printk: Release console_sem after logbuf_lock
-rw-r--r--kernel/lockdep.c30
-rw-r--r--kernel/printk.c24
2 files changed, 41 insertions, 13 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 628276d05915..3956f5149e25 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2481,15 +2481,10 @@ mark_held_locks(struct task_struct *curr, enum mark_type mark)
2481/* 2481/*
2482 * Hardirqs will be enabled: 2482 * Hardirqs will be enabled:
2483 */ 2483 */
2484void trace_hardirqs_on_caller(unsigned long ip) 2484static void __trace_hardirqs_on_caller(unsigned long ip)
2485{ 2485{
2486 struct task_struct *curr = current; 2486 struct task_struct *curr = current;
2487 2487
2488 time_hardirqs_on(CALLER_ADDR0, ip);
2489
2490 if (unlikely(!debug_locks || current->lockdep_recursion))
2491 return;
2492
2493 if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) 2488 if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
2494 return; 2489 return;
2495 2490
@@ -2505,8 +2500,6 @@ void trace_hardirqs_on_caller(unsigned long ip)
2505 /* we'll do an OFF -> ON transition: */ 2500 /* we'll do an OFF -> ON transition: */
2506 curr->hardirqs_enabled = 1; 2501 curr->hardirqs_enabled = 1;
2507 2502
2508 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2509 return;
2510 if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) 2503 if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
2511 return; 2504 return;
2512 /* 2505 /*
@@ -2528,6 +2521,21 @@ void trace_hardirqs_on_caller(unsigned long ip)
2528 curr->hardirq_enable_event = ++curr->irq_events; 2521 curr->hardirq_enable_event = ++curr->irq_events;
2529 debug_atomic_inc(hardirqs_on_events); 2522 debug_atomic_inc(hardirqs_on_events);
2530} 2523}
2524
2525void trace_hardirqs_on_caller(unsigned long ip)
2526{
2527 time_hardirqs_on(CALLER_ADDR0, ip);
2528
2529 if (unlikely(!debug_locks || current->lockdep_recursion))
2530 return;
2531
2532 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2533 return;
2534
2535 current->lockdep_recursion = 1;
2536 __trace_hardirqs_on_caller(ip);
2537 current->lockdep_recursion = 0;
2538}
2531EXPORT_SYMBOL(trace_hardirqs_on_caller); 2539EXPORT_SYMBOL(trace_hardirqs_on_caller);
2532 2540
2533void trace_hardirqs_on(void) 2541void trace_hardirqs_on(void)
@@ -2577,7 +2585,7 @@ void trace_softirqs_on(unsigned long ip)
2577{ 2585{
2578 struct task_struct *curr = current; 2586 struct task_struct *curr = current;
2579 2587
2580 if (unlikely(!debug_locks)) 2588 if (unlikely(!debug_locks || current->lockdep_recursion))
2581 return; 2589 return;
2582 2590
2583 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) 2591 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
@@ -2588,6 +2596,7 @@ void trace_softirqs_on(unsigned long ip)
2588 return; 2596 return;
2589 } 2597 }
2590 2598
2599 current->lockdep_recursion = 1;
2591 /* 2600 /*
2592 * We'll do an OFF -> ON transition: 2601 * We'll do an OFF -> ON transition:
2593 */ 2602 */
@@ -2602,6 +2611,7 @@ void trace_softirqs_on(unsigned long ip)
2602 */ 2611 */
2603 if (curr->hardirqs_enabled) 2612 if (curr->hardirqs_enabled)
2604 mark_held_locks(curr, SOFTIRQ); 2613 mark_held_locks(curr, SOFTIRQ);
2614 current->lockdep_recursion = 0;
2605} 2615}
2606 2616
2607/* 2617/*
@@ -2611,7 +2621,7 @@ void trace_softirqs_off(unsigned long ip)
2611{ 2621{
2612 struct task_struct *curr = current; 2622 struct task_struct *curr = current;
2613 2623
2614 if (unlikely(!debug_locks)) 2624 if (unlikely(!debug_locks || current->lockdep_recursion))
2615 return; 2625 return;
2616 2626
2617 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) 2627 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
diff --git a/kernel/printk.c b/kernel/printk.c
index 35185392173f..37dff3429adb 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -782,7 +782,7 @@ static inline int can_use_console(unsigned int cpu)
782static int console_trylock_for_printk(unsigned int cpu) 782static int console_trylock_for_printk(unsigned int cpu)
783 __releases(&logbuf_lock) 783 __releases(&logbuf_lock)
784{ 784{
785 int retval = 0; 785 int retval = 0, wake = 0;
786 786
787 if (console_trylock()) { 787 if (console_trylock()) {
788 retval = 1; 788 retval = 1;
@@ -795,12 +795,14 @@ static int console_trylock_for_printk(unsigned int cpu)
795 */ 795 */
796 if (!can_use_console(cpu)) { 796 if (!can_use_console(cpu)) {
797 console_locked = 0; 797 console_locked = 0;
798 up(&console_sem); 798 wake = 1;
799 retval = 0; 799 retval = 0;
800 } 800 }
801 } 801 }
802 printk_cpu = UINT_MAX; 802 printk_cpu = UINT_MAX;
803 spin_unlock(&logbuf_lock); 803 spin_unlock(&logbuf_lock);
804 if (wake)
805 up(&console_sem);
804 return retval; 806 return retval;
805} 807}
806static const char recursion_bug_msg [] = 808static const char recursion_bug_msg [] =
@@ -1242,7 +1244,7 @@ void console_unlock(void)
1242{ 1244{
1243 unsigned long flags; 1245 unsigned long flags;
1244 unsigned _con_start, _log_end; 1246 unsigned _con_start, _log_end;
1245 unsigned wake_klogd = 0; 1247 unsigned wake_klogd = 0, retry = 0;
1246 1248
1247 if (console_suspended) { 1249 if (console_suspended) {
1248 up(&console_sem); 1250 up(&console_sem);
@@ -1251,6 +1253,7 @@ void console_unlock(void)
1251 1253
1252 console_may_schedule = 0; 1254 console_may_schedule = 0;
1253 1255
1256again:
1254 for ( ; ; ) { 1257 for ( ; ; ) {
1255 spin_lock_irqsave(&logbuf_lock, flags); 1258 spin_lock_irqsave(&logbuf_lock, flags);
1256 wake_klogd |= log_start - log_end; 1259 wake_klogd |= log_start - log_end;
@@ -1271,8 +1274,23 @@ void console_unlock(void)
1271 if (unlikely(exclusive_console)) 1274 if (unlikely(exclusive_console))
1272 exclusive_console = NULL; 1275 exclusive_console = NULL;
1273 1276
1277 spin_unlock(&logbuf_lock);
1278
1274 up(&console_sem); 1279 up(&console_sem);
1280
1281 /*
1282 * Someone could have filled up the buffer again, so re-check if there's
1283 * something to flush. In case we cannot trylock the console_sem again,
1284 * there's a new owner and the console_unlock() from them will do the
1285 * flush, no worries.
1286 */
1287 spin_lock(&logbuf_lock);
1288 if (con_start != log_end)
1289 retry = 1;
1275 spin_unlock_irqrestore(&logbuf_lock, flags); 1290 spin_unlock_irqrestore(&logbuf_lock, flags);
1291 if (retry && console_trylock())
1292 goto again;
1293
1276 if (wake_klogd) 1294 if (wake_klogd)
1277 wake_up_klogd(); 1295 wake_up_klogd();
1278} 1296}