[compiler-rt] r188291 - tsan: intercept getaddrinfo

[Dmitry Vyukov]

The common interceptor was disabled, because it causes recursion.
The good question is why this interceptor won't cause recursion... I
guess it will.


On Wed, Aug 14, 2013 at 12:03 PM, Evgeniy Stepanov
<eugeni.stepanov at gmail.com> wrote:
> We already have a common interceptor for getaddrinfo.
> How does this even work?
>
> On Wed, Aug 14, 2013 at 9:17 AM, Kostya Serebryany <kcc at google.com> wrote:
>> Do we have a test?
>>
>>
>> On Tue, Aug 13, 2013 at 8:51 PM, Dmitry Vyukov <dvyukov at google.com> wrote:
>>>
>>> Author: dvyukov
>>> Date: Tue Aug 13 11:51:27 2013
>>> New Revision: 188291
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=188291&view=rev
>>> Log:
>>> tsan: intercept getaddrinfo
>>> This is necessary to prevent false positives, see:
>>> https://code.google.com/p/thread-sanitizer/issues/detail?id=25
>>>
>>>
>>> Modified:
>>>     compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
>>>
>>> Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc?rev=188291&r1=188290&r2=188291&view=diff
>>>
>>> ==============================================================================
>>> --- compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc (original)
>>> +++ compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc Tue Aug 13
>>> 11:51:27 2013
>>> @@ -1735,6 +1735,20 @@ TSAN_INTERCEPTOR(int, gettimeofday, void
>>>    return REAL(gettimeofday)(tv, tz);
>>>  }
>>>
>>> +TSAN_INTERCEPTOR(int, getaddrinfo, void *node, void *service,
>>> +    void *hints, void *rv) {
>>> +  SCOPED_TSAN_INTERCEPTOR(getaddrinfo, node, service, hints, rv);
>>> +  // We miss atomic synchronization in getaddrinfo,
>>> +  // and can report false race between malloc and free
>>> +  // inside of getaddrinfo. So ignore memory accesses.
>>> +  IgnoreCtl(thr, true, true);
>>> +  IgnoreCtl(thr, false, true);
>>> +  int res = REAL(getaddrinfo)(node, service, hints, rv);
>>> +  IgnoreCtl(thr, true, false);
>>> +  IgnoreCtl(thr, false, false);
>>
>>
>> The combination of 8 bool values looks bad.
>> Can we have short names somewhere, like void IgnoreReadsBegin(thr)
>> {IgnoreCtl(thr, false, true)} ?
>>
>> -kcc
>>
>>
>>>
>>> +  return res;
>>> +}
>>> +
>>>  // Linux kernel has a bug that leads to kernel deadlock if a process
>>>  // maps TBs of memory and then calls mlock().
>>>  static void MlockIsUnsupported() {
>>> @@ -2056,6 +2070,7 @@ void InitializeInterceptors() {
>>>    TSAN_INTERCEPT(usleep);
>>>    TSAN_INTERCEPT(nanosleep);
>>>    TSAN_INTERCEPT(gettimeofday);
>>> +  TSAN_INTERCEPT(getaddrinfo);
>>>
>>>    TSAN_INTERCEPT(mlock);
>>>    TSAN_INTERCEPT(munlock);
>>>
>>>
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>>
>>
>>
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