From: Pavel Machek <pavel@ucw.cz>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <len.brown@intel.com>,
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 13:54:31 +0100 [thread overview]
Message-ID: <20161202125431.GB5869@amd> (raw)
In-Reply-To: <20161201203154.mwt5x736g7z6jh3o@treble>
[-- Attachment #1: Type: text/plain, Size: 1963 bytes --]
Hi!
> Resuming from a suspend operation is showing a KASAN false positive
> warning:
> KASAN instrumentation poisons the stack when entering a function and
> unpoisons it when exiting the function. However, in the suspend path,
> some functions never return, so their stack never gets unpoisoned,
> resulting in stale KASAN shadow data which can cause later false
> positive warnings like the one above.
>
> Reported-by: Scott Bauer <scott.bauer@intel.com>
> Suggested-by: Dmitry Vyukov <dvyukov@google.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
> ---
> 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
Well... you may want to add note to kasan_unpoison_shadow()
/*
* This is called by early resume code, with cpu not yer properly
* resumed. In particular, %gs may not be set up, and thus current
* is not available.
*/
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]
next prev parent reply other threads:[~2016-12-02 12:54 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 [this message]
2016-12-02 13:41 ` Andrey Ryabinin
2016-12-02 14:01 ` Josh Poimboeuf
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20161202125431.GB5869@amd \
--to=pavel@ucw.cz \
--cc=aryabinin@virtuozzo.com \
--cc=dvyukov@google.com \
--cc=glider@google.com \
--cc=jpoimboe@redhat.com \
--cc=kasan-dev@googlegroups.com \
--cc=len.brown@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=rjw@rjwysocki.net \
--cc=scott.bauer@intel.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).