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authorMitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>2011-12-07 03:29:10 -0500
committerIngo Molnar <mingo@elte.hu>2011-12-07 03:27:11 -0500
commitd2db6610219cbcadceea6c43ee03d89068b7d759 (patch)
treeee5268661f4ab1a8b6119e7e00aa16500efe6c3e
parent565cbc3e934f221369a656b4469a044aa4c3f2a8 (diff)
x86: Add stack top margin for stack overflow checking
It seems that a margin for stack overflow checking is added to top of a kernel stack but is not added to IRQ and exception stacks in stack_overflow_check(). Therefore, the overflows of IRQ and exception stacks are always detected only after they actually occurred and data corruption might occur due to them. This patch adds the margin to top of IRQ and exception stacks as well as a kernel stack to enhance reliability. Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20111207082910.9847.3359.stgit@ltc219.sdl.hitachi.co.jp [ removed the #undef - we typically don't do that for uncommon names ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/kernel/irq_64.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 54e2b2b2e250..d04d3ecded62 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -38,6 +38,7 @@ int sysctl_panic_on_stackoverflow;
38static inline void stack_overflow_check(struct pt_regs *regs) 38static inline void stack_overflow_check(struct pt_regs *regs)
39{ 39{
40#ifdef CONFIG_DEBUG_STACKOVERFLOW 40#ifdef CONFIG_DEBUG_STACKOVERFLOW
41#define STACK_TOP_MARGIN 128
41 struct orig_ist *oist; 42 struct orig_ist *oist;
42 u64 irq_stack_top, irq_stack_bottom; 43 u64 irq_stack_top, irq_stack_bottom;
43 u64 estack_top, estack_bottom; 44 u64 estack_top, estack_bottom;
@@ -47,17 +48,18 @@ static inline void stack_overflow_check(struct pt_regs *regs)
47 return; 48 return;
48 49
49 if (regs->sp >= curbase + sizeof(struct thread_info) + 50 if (regs->sp >= curbase + sizeof(struct thread_info) +
50 sizeof(struct pt_regs) + 128 && 51 sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
51 regs->sp <= curbase + THREAD_SIZE) 52 regs->sp <= curbase + THREAD_SIZE)
52 return; 53 return;
53 54
54 irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack); 55 irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack) +
56 STACK_TOP_MARGIN;
55 irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr); 57 irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
56 if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom) 58 if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
57 return; 59 return;
58 60
59 oist = &__get_cpu_var(orig_ist); 61 oist = &__get_cpu_var(orig_ist);
60 estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ; 62 estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN;
61 estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1]; 63 estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
62 if (regs->sp >= estack_top && regs->sp <= estack_bottom) 64 if (regs->sp >= estack_top && regs->sp <= estack_bottom)
63 return; 65 return;