From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
linux-pm@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Scott Bauer <scott.bauer@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
Alexander Potapenko <glider@google.com>,
kasan-dev <kasan-dev@googlegroups.com>
Subject: Re: [PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume
Date: Fri, 2 Dec 2016 08:01:47 -0600 [thread overview]
Message-ID: <20161202140147.gvj452hmlbxnstrg@treble> (raw)
In-Reply-To: <5144d695-7ac4-f992-5239-91c772b0c121@virtuozzo.com>
On Fri, Dec 02, 2016 at 04:41:09PM +0300, Andrey Ryabinin wrote:
>
>
> 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.
That is better indeed, will do a v3.
--
Josh
next prev parent reply other threads:[~2016-12-02 14:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-29 18:13 BUG: KASAN: stack-out-of-bounds in unwind_get_return_address Scott Bauer
2016-11-30 18:35 ` Josh Poimboeuf
2016-11-30 19:02 ` Scott Bauer
2016-11-30 23:10 ` [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf
2016-12-01 9:05 ` Andrey Ryabinin
2016-12-01 14:58 ` Josh Poimboeuf
2016-12-01 16:45 ` Josh Poimboeuf
2016-12-01 16:51 ` Dmitry Vyukov
2016-12-01 17:13 ` Josh Poimboeuf
2016-12-01 17:27 ` Dmitry Vyukov
2016-12-01 17:34 ` Josh Poimboeuf
2016-12-01 17:47 ` Dmitry Vyukov
2016-12-01 17:56 ` Josh Poimboeuf
2016-12-01 20:31 ` [PATCH v2] " Josh Poimboeuf
2016-12-02 9:44 ` Dmitry Vyukov
2016-12-02 12:54 ` Pavel Machek
2016-12-02 13:41 ` Andrey Ryabinin
2016-12-02 14:01 ` Josh Poimboeuf [this message]
2016-12-02 14:02 ` Dmitry Vyukov
2016-12-02 14:42 ` [PATCH v3] " Josh Poimboeuf
2016-12-02 14:45 ` Andrey Ryabinin
2016-12-02 15:08 ` Josh Poimboeuf
2016-12-02 17:42 ` [PATCH v4] " Josh Poimboeuf
2016-12-02 20:55 ` Andrey Ryabinin
2016-12-02 21:09 ` Pavel Machek
2016-12-02 21:57 ` Josh Poimboeuf
2016-12-08 0:10 ` Rafael J. Wysocki
2016-12-01 14:04 ` [PATCH] " Rafael J. Wysocki
2016-12-01 16:53 ` Josh Poimboeuf
2016-12-01 17:05 ` Rafael J. Wysocki
2016-12-02 10:15 ` Ingo Molnar
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