[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>

1 files changed, 17 insertions, 1 deletions

diff --git a/arch/i386/kernel/cpu/cyrix.c b/arch/i386/kernel/cpu/cyrix.c
index 75015975d038..00f2e058797c 100644
--- a/arch/i386/kernel/cpu/cyrix.c
+++ b/arch/i386/kernel/cpu/cyrix.c
@@ -345,7 +345,7 @@ static void __init init_cyrix(struct cpuinfo_x86 *c)
 /*
  * Handle National Semiconductor branded processors
  */
-static void __devinit init_nsc(struct cpuinfo_x86 *c)
+static void __init init_nsc(struct cpuinfo_x86 *c)
 {
         /* There may be GX1 processors in the wild that are branded
          * NSC and not Cyrix.
@@ -444,6 +444,14 @@ int __init cyrix_init_cpu(void)
 
 //early_arch_initcall(cyrix_init_cpu);
 
+static int __init cyrix_exit_cpu(void)
+{
+        cpu_devs[X86_VENDOR_CYRIX] = NULL;
+        return 0;
+}
+
+late_initcall(cyrix_exit_cpu);
+
 static struct cpu_dev nsc_cpu_dev __initdata = {
         .c_vendor       = "NSC",
         .c_ident        = { "Geode by NSC" },
@@ -458,3 +466,11 @@ int __init nsc_init_cpu(void)
 }
 
 //early_arch_initcall(nsc_init_cpu);
+
+static int __init nsc_exit_cpu(void)
+{
+        cpu_devs[X86_VENDOR_NSC] = NULL;
+        return 0;
+}
+
+late_initcall(nsc_exit_cpu);