[PATCH] i386 cpu hotplug: don't access freed memory
i386 CPU init code accesses freed init memory when booting a newly-started
processor after CPU hotplug. The cpu_devs array is searched to find the
vendor and it contains pointers to freed data.
Fix that by:
1. Zeroing entries for freed vendor data after bootup.
2. Changing Transmeta, NSC and UMC to all __init[data].
3. Printing a warning (once only) and setting this_cpu
to a safe default when the vendor is not found.
This does not change behavior for AMD systems. They were broken already
but no error was reported.
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index 15aee26..7eb9213 100644
--- a/arch/i386/kernel/cpu/common.c
+++ b/arch/i386/kernel/cpu/common.c
@@ -44,6 +44,7 @@
static struct cpu_dev default_cpu = {
.c_init = default_init,
+ .c_vendor = "Unknown",
};
static struct cpu_dev * this_cpu = &default_cpu;
@@ -150,6 +151,7 @@
{
char *v = c->x86_vendor_id;
int i;
+ static int printed;
for (i = 0; i < X86_VENDOR_NUM; i++) {
if (cpu_devs[i]) {
@@ -159,10 +161,17 @@
c->x86_vendor = i;
if (!early)
this_cpu = cpu_devs[i];
- break;
+ return;
}
}
}
+ if (!printed) {
+ printed++;
+ printk(KERN_ERR "CPU: Vendor unknown, using generic init.\n");
+ printk(KERN_ERR "CPU: Your system may be unstable.\n");
+ }
+ c->x86_vendor = X86_VENDOR_UNKNOWN;
+ this_cpu = &default_cpu;
}