[llvm] r279605 - Preserve a pointer to the newly allocated signal stack as well. That too

[Vitaly Buka via llvm-commits]

+kcc

On Wed, Aug 24, 2016 at 8:45 PM Vitaly Buka <vitalybuka at google.com> wrote:

> I submitted quick fix https://reviews.llvm.org/D23864 to recover bots.
> Another working solution is to make Asan to set size greeter than one in
> Signals.inc
>
> On Wed, Aug 24, 2016 at 7:13 PM Vitaly Buka <vitalybuka at google.com> wrote:
>
>> This patch conflicts with asan
>>
>> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/15763/steps/check-clang%20asan/logs/stdio
>>
>>
>> On Tue, Aug 23, 2016 at 8:50 PM Chandler Carruth via llvm-commits <
>> llvm-commits at lists.llvm.org> wrote:
>>
>>> Author: chandlerc
>>> Date: Tue Aug 23 22:42:51 2016
>>> New Revision: 279605
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=279605&view=rev
>>> Log:
>>> Preserve a pointer to the newly allocated signal stack as well. That too
>>> is flagged by LSan at least among leak detectors.
>>>
>>> Modified:
>>>     llvm/trunk/lib/Support/Unix/Signals.inc
>>>
>>> Modified: llvm/trunk/lib/Support/Unix/Signals.inc
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Unix/Signals.inc?rev=279605&r1=279604&r2=279605&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/Support/Unix/Signals.inc (original)
>>> +++ llvm/trunk/lib/Support/Unix/Signals.inc Tue Aug 23 22:42:51 2016
>>> @@ -120,11 +120,12 @@ static void RegisterHandler(int Signal)
>>>  }
>>>
>>>  #if defined(HAVE_SIGALTSTACK)
>>> -// Hold onto the old alternate signal stack so that it's not reported
>>> as a leak.
>>> -// We don't make any attempt to remove our alt signal stack if we
>>> remove our
>>> -// signal handlers; that can't be done reliably if someone else is also
>>> trying
>>> -// to do the same thing.
>>> +// Hold onto both the old and new alternate signal stack so that it's
>>> not
>>> +// reported as a leak. We don't make any attempt to remove our alt
>>> signal
>>> +// stack if we remove our signal handlers; that can't be done reliably
>>> if
>>> +// someone else is also trying to do the same thing.
>>>  static stack_t OldAltStack;
>>> +static void* NewAltStackPointer;
>>>
>>>  static void CreateSigAltStack() {
>>>    const size_t AltStackSize = MINSIGSTKSZ + 64 * 1024;
>>> @@ -140,6 +141,7 @@ static void CreateSigAltStack() {
>>>
>>>    stack_t AltStack = {};
>>>    AltStack.ss_sp = reinterpret_cast<char *>(malloc(AltStackSize));
>>> +  NewAltStackPointer = AltStack.ss_sp; // Save to avoid reporting a
>>> leak.
>>>    AltStack.ss_size = AltStackSize;
>>>    if (sigaltstack(&AltStack, &OldAltStack) != 0)
>>>      free(AltStack.ss_sp);
>>>
>>>
>>> _______________________________________________
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>>> llvm-commits at lists.llvm.org
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>>>
>>
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