diff options
| -rw-r--r-- | kernel/printk.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/kernel/printk.c b/kernel/printk.c index 444b770c9595..4ab0164bcf84 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -37,6 +37,8 @@ #include <linux/ratelimit.h> #include <linux/kmsg_dump.h> #include <linux/syslog.h> +#include <linux/cpu.h> +#include <linux/notifier.h> #include <asm/uaccess.h> @@ -985,6 +987,32 @@ void resume_console(void) } /** + * console_cpu_notify - print deferred console messages after CPU hotplug + * @self: notifier struct + * @action: CPU hotplug event + * @hcpu: unused + * + * If printk() is called from a CPU that is not online yet, the messages + * will be spooled but will not show up on the console. This function is + * called when a new CPU comes online (or fails to come up), and ensures + * that any such output gets printed. + */ +static int __cpuinit console_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + switch (action) { + case CPU_ONLINE: + case CPU_DEAD: + case CPU_DYING: + case CPU_DOWN_FAILED: + case CPU_UP_CANCELED: + acquire_console_sem(); + release_console_sem(); + } + return NOTIFY_OK; +} + +/** * acquire_console_sem - lock the console system for exclusive use. * * Acquires a semaphore which guarantees that the caller has @@ -1371,7 +1399,7 @@ int unregister_console(struct console *console) } EXPORT_SYMBOL(unregister_console); -static int __init disable_boot_consoles(void) +static int __init printk_late_init(void) { struct console *con; @@ -1382,9 +1410,10 @@ static int __init disable_boot_consoles(void) unregister_console(con); } } + hotcpu_notifier(console_cpu_notify, 0); return 0; } -late_initcall(disable_boot_consoles); +late_initcall(printk_late_init); #if defined CONFIG_PRINTK |