On 12/01/2016 11:31 PM, Josh Poimboeuf wrote:
> arch/x86/kernel/acpi/wakeup_64.S | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/arch/x86/kernel/acpi/wakeup_64.S > b/arch/x86/kernel/acpi/wakeup_64.S > index 169963f..1df9b75 100644 > --- a/arch/x86/kernel/acpi/wakeup_64.S > +++ b/arch/x86/kernel/acpi/wakeup_64.S > @@ -109,6 +109,22 @@ ENTRY(do_suspend_lowlevel) > movq pt_regs_r14(%rax), %r14 > movq pt_regs_r15(%rax), %r15 > > +#ifdef CONFIG_KASAN > + /* > + * The suspend path may have poisoned some areas deeper in the stack, > + * which we now need to unpoison. > + * > + * We can't call kasan_unpoison_task_stack_below() because it uses %gs > + * for 'current', which hasn't been set up yet. Instead, calculate the > + * stack range manually and call kasan_unpoison_shadow(). > + */ > + movq %rsp, %rdi > + andq $CURRENT_MASK, %rdi > + movq %rsp, %rsi > + xorq %rdi, %rsi > + call kasan_unpoison_shadow > +#endif > + Looks good, but in fact we can use kasan_unpoison_task_stack_below(). We just need to change it a little: diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 70c0097..e779236 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -80,7 +80,9 @@ void kasan_unpoison_task_stack(struct task_struct *task) /* Unpoison the stack for the current task beyond a watermark sp value. */ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark) { - __kasan_unpoison_stack(current, watermark); + void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1)); + + kasan_unpoison_shadow(base, watermark - base); } With this we don't have to calculate stack range in assembly.