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authorMitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>2011-11-29 15:08:45 +0900
committerIngo Molnar <mingo@elte.hu>2011-12-05 11:37:48 +0100
commit467e6b7a7c0eb792ebaf322ddb7363742b4ead40 (patch)
tree9ed64d72d0a63fbb4dd327af7446c4d1f205118e /arch
parent55af77969fbd7a841838220ea2287432e0da8ae5 (diff)
downloadop-kernel-dev-467e6b7a7c0eb792ebaf322ddb7363742b4ead40.zip
op-kernel-dev-467e6b7a7c0eb792ebaf322ddb7363742b4ead40.tar.gz
x86: Clean up the range of stack overflow checking
The overflow checking of kernel stack checks if the stack pointer points to the available kernel stack range, which is derived from the original overflow checking. It is clear that curbase address is always less than low boundary of available kernel stack. So, this patch removes the first condition that checks if the pointer is higher than curbase. 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/20111129060845.11076.40916.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.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 42552b0..54e2b2b 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -46,10 +46,9 @@ static inline void stack_overflow_check(struct pt_regs *regs)
if (user_mode_vm(regs))
return;
- if (regs->sp >= curbase &&
- regs->sp <= curbase + THREAD_SIZE &&
- regs->sp >= curbase + sizeof(struct thread_info) +
- sizeof(struct pt_regs) + 128)
+ if (regs->sp >= curbase + sizeof(struct thread_info) +
+ sizeof(struct pt_regs) + 128 &&
+ regs->sp <= curbase + THREAD_SIZE)
return;
irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack);
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