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Re: [PATCHv3][PING] Enable -fsanitize-recover for KASan
- From: Alexey Samsonov <samsonov at google dot com>
- To: Yury Gribov <y dot gribov at samsung dot com>
- Cc: Jakub Jelinek <jakub at redhat dot com>, Konstantin Serebryany <konstantin dot s dot serebryany at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Dmitry Vyukov <dvyukov at google dot com>, Andrey Ryabinin <a dot ryabinin at samsung dot com>, Konstantin Khlebnikov <k dot khlebnikov at samsung dot com>
- Date: Tue, 30 Sep 2014 10:26:39 -0700
- Subject: Re: [PATCHv3][PING] Enable -fsanitize-recover for KASan
- Authentication-results: sourceware.org; auth=none
- References: <54095E23 dot 6050900 at samsung dot com> <5416B3A2 dot 4050200 at samsung dot com> <54299507 dot 7090800 at samsung dot com> <20140929174357 dot GH17454 at tucnak dot redhat dot com> <CAGQ9bdzcCO6CfQ7nG+xeAh63fs-GASiTExTvZfjJtMA67_4feQ at mail dot gmail dot com> <CAGSYnCPwbgZ++2Jt2vE6-ytveSJwSQPZT5umLeKPVWsVjWzwPQ at mail dot gmail dot com> <20140929231720 dot GI17454 at tucnak dot redhat dot com> <CAGSYnCPAN83v+JOyw-jMLUEE2YjaNQykdTCG4rdd=o_ieC4vFA at mail dot gmail dot com> <CAGQ9bdyWWNMt4m9jO2N1nzvVFjVuT1zbyey362WvnMxJZmNkBw at mail dot gmail dot com> <20140930054027 dot GJ17454 at tucnak dot redhat dot com> <542A56C0 dot 2030506 at samsung dot com>
On Tue, Sep 30, 2014 at 12:07 AM, Yury Gribov <y.gribov@samsung.com> wrote:
> On 09/30/2014 09:40 AM, Jakub Jelinek wrote:
>>
>> On Mon, Sep 29, 2014 at 05:24:02PM -0700, Konstantin Serebryany wrote:
>>>>
>>>> I don't think we ever going to support recovery for regular ASan
>>>> (Kostya, correct me if I'm wrong).
>>>
>>>
>>> I hope so too.
>>> Another point is that with asan-instrumentation-with-call-threshold=0
>>> (instrumentation with callbacks)
>>
>>
>> The normal (non-recovery) callbacks are __attribute__((noreturn)) for
>> performance reasons, and you do need different callbacks and different
>> generated code if you want to recover (after the callback you need jump
>> back to a basic block after the conditional jump).
>> So, in that case you would need -fsanitize-recover=address.
>>
>>>> I see no problem in enabling -fsanitize-recover by default for
>>>> -fsanitize=undefined and
>>>
>>>
>>> This becomes more interesting when we use asan and ubsan together.
>>
>>
>> That is fairly common case.
>
>
> I think we can summarize:
> * the current option -fsanitize-recover is misleading; it's really
> -fubsan-recover
> * we need a way to selectively enable/disable recovery for different
> sanitizers
>
> The most promininet solution seems to be
> * allow -fsanitize-recover=tgt1,tgt2 syntax
> * -fsanitize-recover wo options would still mean UBSan recovery
>
> The question is what to do with -fno-sanitize-recover then.
We can make -f(no-)?sanitize-recover= flags accept the same values as
-f(no-)?sanitize= flags. In this case,
"-fsanitize-recover" will be a deprecated alias of
"-fsanitize-recover=undefined", and
"-fno-sanitize-recover" will be a deprecated alias of
"-fno-sanitize-recover=undefined".
If a user provides "-fsanitize-recover=address", we can instruct the
instrumentation pass to
use recoverable instrumentation.
>
> -Y
>
--
Alexey Samsonov, Mountain View, CA