From: Mitsuo Hayasaka Date: Tue, 29 Nov 2011 06:08:45 +0000 (+0900) Subject: x86: Clean up the range of stack overflow checking X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=467e6b7a7c0eb792ebaf322ddb7363742b4ead40;p=linux-beck.git 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 Cc: yrl.pp-manager.tt@hitachi.com Cc: Randy Dunlap Link: http://lkml.kernel.org/r/20111129060845.11076.40916.stgit@ltc219.sdl.hitachi.co.jp Signed-off-by: Ingo Molnar Cc: "H. Peter Anvin" --- diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c index 42552b0dce6a..54e2b2b2e250 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);