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-rw-r--r--kernel/printk/printk.c47
1 files changed, 32 insertions, 15 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 6bb77eff502d..f426a2b12a9b 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -213,17 +213,36 @@ static int nr_ext_console_drivers;
static int __down_trylock_console_sem(unsigned long ip)
{
- if (down_trylock(&console_sem))
+ int lock_failed;
+ unsigned long flags;
+
+ /*
+ * Here and in __up_console_sem() we need to be in safe mode,
+ * because spindump/WARN/etc from under console ->lock will
+ * deadlock in printk()->down_trylock_console_sem() otherwise.
+ */
+ printk_safe_enter_irqsave(flags);
+ lock_failed = down_trylock(&console_sem);
+ printk_safe_exit_irqrestore(flags);
+
+ if (lock_failed)
return 1;
mutex_acquire(&console_lock_dep_map, 0, 1, ip);
return 0;
}
#define down_trylock_console_sem() __down_trylock_console_sem(_RET_IP_)
-#define up_console_sem() do { \
- mutex_release(&console_lock_dep_map, 1, _RET_IP_);\
- up(&console_sem);\
-} while (0)
+static void __up_console_sem(unsigned long ip)
+{
+ unsigned long flags;
+
+ mutex_release(&console_lock_dep_map, 1, ip);
+
+ printk_safe_enter_irqsave(flags);
+ up(&console_sem);
+ printk_safe_exit_irqrestore(flags);
+}
+#define up_console_sem() __up_console_sem(_RET_IP_)
/*
* This is used for debugging the mess that is the VT code by
@@ -1689,7 +1708,7 @@ asmlinkage int vprintk_emit(int facility, int level,
boot_delay_msec(level);
printk_delay();
- local_irq_save(flags);
+ printk_safe_enter_irqsave(flags);
this_cpu = smp_processor_id();
/*
@@ -1705,13 +1724,12 @@ asmlinkage int vprintk_emit(int facility, int level,
*/
if (!oops_in_progress && !lockdep_recursing(current)) {
recursion_bug = true;
- local_irq_restore(flags);
+ printk_safe_exit_irqrestore(flags);
return 0;
}
zap_locks();
}
- lockdep_off();
/* This stops the holder of console_sem just where we want him */
raw_spin_lock(&logbuf_lock);
logbuf_cpu = this_cpu;
@@ -1771,12 +1789,10 @@ asmlinkage int vprintk_emit(int facility, int level,
logbuf_cpu = UINT_MAX;
raw_spin_unlock(&logbuf_lock);
- lockdep_on();
- local_irq_restore(flags);
+ printk_safe_exit_irqrestore(flags);
/* If called from the scheduler, we can not call up(). */
if (!in_sched) {
- lockdep_off();
/*
* Try to acquire and then immediately release the console
* semaphore. The release will print out buffers and wake up
@@ -1784,7 +1800,6 @@ asmlinkage int vprintk_emit(int facility, int level,
*/
if (console_trylock())
console_unlock();
- lockdep_on();
}
return printed_len;
@@ -2209,7 +2224,8 @@ again:
size_t len;
int level;
- raw_spin_lock_irqsave(&logbuf_lock, flags);
+ printk_safe_enter_irqsave(flags);
+ raw_spin_lock(&logbuf_lock);
if (seen_seq != log_next_seq) {
wake_klogd = true;
seen_seq = log_next_seq;
@@ -2259,7 +2275,7 @@ skip:
stop_critical_timings(); /* don't trace print latency */
call_console_drivers(level, ext_text, ext_len, text, len);
start_critical_timings();
- local_irq_restore(flags);
+ printk_safe_exit_irqrestore(flags);
if (do_cond_resched)
cond_resched();
@@ -2282,7 +2298,8 @@ skip:
*/
raw_spin_lock(&logbuf_lock);
retry = console_seq != log_next_seq;
- raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+ raw_spin_unlock(&logbuf_lock);
+ printk_safe_exit_irqrestore(flags);
if (retry && console_trylock())
goto again;