On Mon, Nov 07, 2011 at 02:52:35PM +0900, Mitsuo Hayasaka wrote: > The kernel stack overflow is checked in stack_overflow_check(), > which may wrongly detect the overflow if the stack pointer > pointed to the kernel stack accidentally. I think you mean to say 'points'. How do we accidently point the stack pointer to the kernel stack? > > This patch adds user-mode-vm checking before it to avoid this > misdetection and bails out early if the user stack is used. > > Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@xxxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> > --- > > arch/x86/kernel/irq_64.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c > index acf8fbf..69bca46 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) + > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
