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-rw-r--r--kernel/printk.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index 2d607f4d1797..22e070f3470a 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -87,6 +87,12 @@ static DEFINE_SEMAPHORE(console_sem);
87struct console *console_drivers; 87struct console *console_drivers;
88EXPORT_SYMBOL_GPL(console_drivers); 88EXPORT_SYMBOL_GPL(console_drivers);
89 89
90#ifdef CONFIG_LOCKDEP
91static struct lockdep_map console_lock_dep_map = {
92 .name = "console_lock"
93};
94#endif
95
90/* 96/*
91 * This is used for debugging the mess that is the VT code by 97 * This is used for debugging the mess that is the VT code by
92 * keeping track if we have the console semaphore held. It's 98 * keeping track if we have the console semaphore held. It's
@@ -1908,12 +1914,14 @@ static int __cpuinit console_cpu_notify(struct notifier_block *self,
1908 */ 1914 */
1909void console_lock(void) 1915void console_lock(void)
1910{ 1916{
1911 BUG_ON(in_interrupt()); 1917 might_sleep();
1918
1912 down(&console_sem); 1919 down(&console_sem);
1913 if (console_suspended) 1920 if (console_suspended)
1914 return; 1921 return;
1915 console_locked = 1; 1922 console_locked = 1;
1916 console_may_schedule = 1; 1923 console_may_schedule = 1;
1924 mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);
1917} 1925}
1918EXPORT_SYMBOL(console_lock); 1926EXPORT_SYMBOL(console_lock);
1919 1927
@@ -1935,6 +1943,7 @@ int console_trylock(void)
1935 } 1943 }
1936 console_locked = 1; 1944 console_locked = 1;
1937 console_may_schedule = 0; 1945 console_may_schedule = 0;
1946 mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_);
1938 return 1; 1947 return 1;
1939} 1948}
1940EXPORT_SYMBOL(console_trylock); 1949EXPORT_SYMBOL(console_trylock);
@@ -2095,6 +2104,7 @@ skip:
2095 local_irq_restore(flags); 2104 local_irq_restore(flags);
2096 } 2105 }
2097 console_locked = 0; 2106 console_locked = 0;
2107 mutex_release(&console_lock_dep_map, 1, _RET_IP_);
2098 2108
2099 /* Release the exclusive_console once it is used */ 2109 /* Release the exclusive_console once it is used */
2100 if (unlikely(exclusive_console)) 2110 if (unlikely(exclusive_console))