[PATCH] CPU hotplug printk fix

In the cpu hotplug case, per-cpu data possibly isn't initialized even the
system state is 'running'.  As the comments say in the original code, some
console drivers assume per-cpu resources have been allocated.  radeon fb is
one such driver, which uses kmalloc.  After a CPU is down, the per-cpu data
of slab is freed, so the system crashed when printing some info.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/printk.c b/kernel/printk.c
index 3a442bf..5092397 100644 (file)
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -588,8 +588,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
                        log_level_unknown = 1;
        }
 
-       if (!cpu_online(smp_processor_id()) &&
-           system_state != SYSTEM_RUNNING) {
+       if (!cpu_online(smp_processor_id())) {
                /*
                 * Some console drivers may assume that per-cpu resources have
                 * been allocated.  So don't allow them to be called by this