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authorMitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>2011-11-29 15:08:21 +0900
committerIngo Molnar <mingo@elte.hu>2011-12-05 11:28:25 +0100
commit69682b625a043b567873e6cda397969b502f0054 (patch)
treef310cd36151a616db033db258824b0b4f3e1db80 /arch
parent8e8da023f5af71662867729db5547dc54786093c (diff)
downloadvexpress-lsk-69682b625a043b567873e6cda397969b502f0054.tar.gz
x86: Add user_mode_vm check in stack_overflow_check
The kernel stack overflow is checked in stack_overflow_check(), which may wrongly detect the overflow if the stack pointer in user space points to the kernel stack intentionally or accidentally. So, the actual overflow is never detected after this misdetection because WARN_ONCE() is used on the detection of it. This patch adds user-mode-vm checking before it to avoid this problem and bails out early if the user stack is used. Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Randy Dunlap <rdunlap@xenotime.net> Link: http://lkml.kernel.org/r/20111129060821.11076.55315.stgit@ltc219.sdl.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/irq_64.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index acf8fbf8fbd..69bca468c47 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -38,6 +38,9 @@ static inline void stack_overflow_check(struct pt_regs *regs)
#ifdef CONFIG_DEBUG_STACKOVERFLOW
u64 curbase = (u64)task_stack_page(current);
+ if (user_mode_vm(regs))
+ return;
+
WARN_ONCE(regs->sp >= curbase &&
regs->sp <= curbase + THREAD_SIZE &&
regs->sp < curbase + sizeof(struct thread_info) +