x86: kernel_thread() -- initialize SS to a known state

Before the kernel_thread was converted into "C" we had
pt_regs::ss set to __KERNEL_DS (by SAVE_ALL asm macro).

Though I must admit I didn't find any *explicit* load of
%ss from this structure the better to be on a safe side
and set it to a known value.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com>
Cc: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1263377768-19600-1-git-send-email-ian.campbell@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c6ee241..02c3ee0 100644 (file)
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -288,6 +288,8 @@ int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
        regs.es = __USER_DS;
        regs.fs = __KERNEL_PERCPU;
        regs.gs = __KERNEL_STACK_CANARY;
        regs.es = __USER_DS;
        regs.fs = __KERNEL_PERCPU;
        regs.gs = __KERNEL_STACK_CANARY;

+#else
+       regs.ss = __KERNEL_DS;

 #endif
 
        regs.orig_ax = -1;
 #endif
 
        regs.orig_ax = -1;