<div dir="ltr">But it doesn't work! <div>Your code in ReInit changes the storage for counters but ti does not flush the guards. </div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Dec 23, 2014 at 12:58 AM, Evgeniy Stepanov <span dir="ltr"><<a href="mailto:eugeni.stepanov@gmail.com" target="_blank">eugeni.stepanov@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">This is the main mode of execution on Android.<br>
And in Chromium.<br>
Better keep it.<br>
<div class="HOEnZb"><div class="h5"><br>
<br>
On Tue, Dec 23, 2014 at 1:53 AM, Kostya Serebryany <<a href="mailto:kcc@google.com">kcc@google.com</a>> wrote:<br>
> I've stumbled upon this test while changing how the coverage logic works...<br>
> Do we need coverage to work after fork but before exec at all?<br>
> It actually doesn't fully work today either, but I want to break it even<br>
> more...<br>
><br>
> On Wed, Jun 4, 2014 at 5:13 AM, Evgeniy Stepanov <<a href="mailto:eugeni.stepanov@gmail.com">eugeni.stepanov@gmail.com</a>><br>
> wrote:<br>
>><br>
>> Author: eugenis<br>
>> Date: Wed Jun 4 07:13:54 2014<br>
>> New Revision: 210180<br>
>><br>
>> URL: <a href="http://llvm.org/viewvc/llvm-project?rev=210180&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=210180&view=rev</a><br>
>> Log:<br>
>> [sancov] Handle fork.<br>
>><br>
>> Reset coverage data on fork().<br>
>> For memory-mapped mode (coverage_direct=1) this helps avoid loss of data<br>
>> (before this change two processes would write to the same file<br>
>> simultaneously).<br>
>> For normal mode, this reduces coverage dump size, because PCs from the<br>
>> parent<br>
>> process are no longer inherited by the child.<br>
>><br>
>> Added:<br>
>> compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork-direct.cc<br>
>> (with props)<br>
>> compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc (with<br>
>> props)<br>
>> Modified:<br>
>> compiler-rt/trunk/lib/asan/asan_interceptors.cc<br>
>> compiler-rt/trunk/lib/asan/asan_interceptors.h<br>
>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h<br>
>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc<br>
>><br>
>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_mapping_libcdep.cc<br>
>><br>
>> Modified: compiler-rt/trunk/lib/asan/asan_interceptors.cc<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_interceptors.cc?rev=210180&r1=210179&r2=210180&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_interceptors.cc?rev=210180&r1=210179&r2=210180&view=diff</a><br>
>><br>
>> ==============================================================================<br>
>> --- compiler-rt/trunk/lib/asan/asan_interceptors.cc (original)<br>
>> +++ compiler-rt/trunk/lib/asan/asan_interceptors.cc Wed Jun 4 07:13:54<br>
>> 2014<br>
>> @@ -697,6 +697,16 @@ INTERCEPTOR(int, __cxa_atexit, void (*fu<br>
>> }<br>
>> #endif // ASAN_INTERCEPT___CXA_ATEXIT<br>
>><br>
>> +#if ASAN_INTERCEPT_FORK<br>
>> +INTERCEPTOR(int, fork, void) {<br>
>> + ENSURE_ASAN_INITED();<br>
>> + if (common_flags()->coverage) CovBeforeFork();<br>
>> + int pid = REAL(fork)();<br>
>> + if (common_flags()->coverage) CovAfterFork(pid);<br>
>> + return pid;<br>
>> +}<br>
>> +#endif // ASAN_INTERCEPT_FORK<br>
>> +<br>
>> #if SANITIZER_WINDOWS<br>
>> INTERCEPTOR_WINAPI(DWORD, CreateThread,<br>
>> void* security, uptr stack_size,<br>
>> @@ -808,6 +818,10 @@ void InitializeAsanInterceptors() {<br>
>> ASAN_INTERCEPT_FUNC(__cxa_atexit);<br>
>> #endif<br>
>><br>
>> +#if ASAN_INTERCEPT_FORK<br>
>> + ASAN_INTERCEPT_FUNC(fork);<br>
>> +#endif<br>
>> +<br>
>> // Some Windows-specific interceptors.<br>
>> #if SANITIZER_WINDOWS<br>
>> InitializeWindowsInterceptors();<br>
>><br>
>> Modified: compiler-rt/trunk/lib/asan/asan_interceptors.h<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_interceptors.h?rev=210180&r1=210179&r2=210180&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_interceptors.h?rev=210180&r1=210179&r2=210180&view=diff</a><br>
>><br>
>> ==============================================================================<br>
>> --- compiler-rt/trunk/lib/asan/asan_interceptors.h (original)<br>
>> +++ compiler-rt/trunk/lib/asan/asan_interceptors.h Wed Jun 4 07:13:54<br>
>> 2014<br>
>> @@ -27,6 +27,7 @@<br>
>> # define ASAN_INTERCEPT_INDEX 1<br>
>> # define ASAN_INTERCEPT_PTHREAD_CREATE 1<br>
>> # define ASAN_INTERCEPT_MLOCKX 1<br>
>> +# define ASAN_INTERCEPT_FORK 1<br>
>> #else<br>
>> # define ASAN_INTERCEPT_ATOLL_AND_STRTOLL 0<br>
>> # define ASAN_INTERCEPT__LONGJMP 0<br>
>> @@ -34,6 +35,7 @@<br>
>> # define ASAN_INTERCEPT_INDEX 0<br>
>> # define ASAN_INTERCEPT_PTHREAD_CREATE 0<br>
>> # define ASAN_INTERCEPT_MLOCKX 0<br>
>> +# define ASAN_INTERCEPT_FORK 0<br>
>> #endif<br>
>><br>
>> #if SANITIZER_FREEBSD || SANITIZER_LINUX<br>
>><br>
>> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h?rev=210180&r1=210179&r2=210180&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h?rev=210180&r1=210179&r2=210180&view=diff</a><br>
>><br>
>> ==============================================================================<br>
>> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h (original)<br>
>> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h Wed Jun 4<br>
>> 07:13:54 2014<br>
>> @@ -193,6 +193,8 @@ void CovPrepareForSandboxing(__sanitizer<br>
>> void SetSandboxingCallback(void (*f)());<br>
>><br>
>> void CovUpdateMapping();<br>
>> +void CovBeforeFork();<br>
>> +void CovAfterFork(int child_pid);<br>
>><br>
>> void InitTlsSize();<br>
>> uptr GetTlsSize();<br>
>><br>
>> Modified:<br>
>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc?rev=210180&r1=210179&r2=210180&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc?rev=210180&r1=210179&r2=210180&view=diff</a><br>
>><br>
>> ==============================================================================<br>
>> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc<br>
>> (original)<br>
>> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc<br>
>> Wed Jun 4 07:13:54 2014<br>
>> @@ -59,6 +59,8 @@ namespace __sanitizer {<br>
>> class CoverageData {<br>
>> public:<br>
>> void Init();<br>
>> + void BeforeFork();<br>
>> + void AfterFork(int child_pid);<br>
>> void Extend(uptr npcs);<br>
>> void Add(uptr pc);<br>
>><br>
>> @@ -86,6 +88,7 @@ class CoverageData {<br>
>> StaticSpinMutex mu;<br>
>><br>
>> void DirectOpen();<br>
>> + void ReInit();<br>
>> };<br>
>><br>
>> static CoverageData coverage_data;<br>
>> @@ -107,23 +110,47 @@ void CoverageData::DirectOpen() {<br>
>> void CoverageData::Init() {<br>
>> pc_array = reinterpret_cast<uptr *>(<br>
>> MmapNoReserveOrDie(sizeof(uptr) * kPcArrayMaxSize, "CovInit"));<br>
>> + pc_fd = kInvalidFd;<br>
>> if (common_flags()->coverage_direct) {<br>
>> atomic_store(&pc_array_size, 0, memory_order_relaxed);<br>
>> atomic_store(&pc_array_index, 0, memory_order_relaxed);<br>
>> } else {<br>
>> - pc_fd = 0;<br>
>> atomic_store(&pc_array_size, kPcArrayMaxSize, memory_order_relaxed);<br>
>> atomic_store(&pc_array_index, 0, memory_order_relaxed);<br>
>> }<br>
>> }<br>
>><br>
>> +void CoverageData::ReInit() {<br>
>> + internal_munmap(pc_array, sizeof(uptr) * kPcArrayMaxSize);<br>
>> + if (pc_fd != kInvalidFd) internal_close(pc_fd);<br>
>> + if (common_flags()->coverage_direct) {<br>
>> + // In memory-mapped mode we must extend the new file to the known<br>
>> array<br>
>> + // size.<br>
>> + uptr size = atomic_load(&pc_array_size, memory_order_relaxed);<br>
>> + Init();<br>
>> + if (size) Extend(size);<br>
>> + } else {<br>
>> + Init();<br>
>> + }<br>
>> +}<br>
>> +<br>
>> +void CoverageData::BeforeFork() {<br>
>> + mu.Lock();<br>
>> +}<br>
>> +<br>
>> +void CoverageData::AfterFork(int child_pid) {<br>
>> + // We are single-threaded so it's OK to release the lock early.<br>
>> + mu.Unlock();<br>
>> + if (child_pid == 0) ReInit();<br>
>> +}<br>
>> +<br>
>> // Extend coverage PC array to fit additional npcs elements.<br>
>> void CoverageData::Extend(uptr npcs) {<br>
>> if (!common_flags()->coverage_direct) return;<br>
>> SpinMutexLock l(&mu);<br>
>><br>
>> - if (!pc_fd) DirectOpen();<br>
>> - CHECK(pc_fd);<br>
>> + if (pc_fd == kInvalidFd) DirectOpen();<br>
>> + CHECK_NE(pc_fd, kInvalidFd);<br>
>><br>
>> uptr size = atomic_load(&pc_array_size, memory_order_relaxed);<br>
>> size += npcs * sizeof(uptr);<br>
>> @@ -324,6 +351,15 @@ int MaybeOpenCovFile(const char *name) {<br>
>> if (!common_flags()->coverage) return -1;<br>
>> return CovOpenFile(true /* packed */, name);<br>
>> }<br>
>> +<br>
>> +void CovBeforeFork() {<br>
>> + coverage_data.BeforeFork();<br>
>> +}<br>
>> +<br>
>> +void CovAfterFork(int child_pid) {<br>
>> + coverage_data.AfterFork(child_pid);<br>
>> +}<br>
>> +<br>
>> } // namespace __sanitizer<br>
>><br>
>> extern "C" {<br>
>><br>
>> Modified:<br>
>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_mapping_libcdep.cc<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_mapping_libcdep.cc?rev=210180&r1=210179&r2=210180&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_mapping_libcdep.cc?rev=210180&r1=210179&r2=210180&view=diff</a><br>
>><br>
>> ==============================================================================<br>
>> ---<br>
>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_mapping_libcdep.cc<br>
>> (original)<br>
>> +++<br>
>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_mapping_libcdep.cc<br>
>> Wed Jun 4 07:13:54 2014<br>
>> @@ -36,8 +36,27 @@<br>
>> namespace __sanitizer {<br>
>><br>
>> static const uptr kMaxNumberOfModules = 1 << 14;<br>
>> +static const uptr kMaxTextSize = 64 * 1024;<br>
>><br>
>> -static char *last_mapping;<br>
>> +struct CachedMapping {<br>
>> + public:<br>
>> + bool TestAndUpdate(const char *new_mapping) {<br>
>> + int new_pid = internal_getpid();<br>
>> + if (last_mapping && last_pid == new_pid &&<br>
>> + internal_strcmp(last_mapping, new_mapping) == 0)<br>
>> + return false;<br>
>> + if (!last_mapping) last_mapping = (char<br>
>> *)InternalAlloc(kMaxTextSize);<br>
>> + last_pid = new_pid;<br>
>> + internal_strncpy(last_mapping, new_mapping, kMaxTextSize);<br>
>> + return true;<br>
>> + }<br>
>> +<br>
>> + private:<br>
>> + char *last_mapping;<br>
>> + int last_pid;<br>
>> +};<br>
>> +<br>
>> +static CachedMapping cached_mapping;<br>
>> static StaticSpinMutex mapping_mu;<br>
>><br>
>> void CovUpdateMapping() {<br>
>> @@ -45,7 +64,6 @@ void CovUpdateMapping() {<br>
>><br>
>> SpinMutexLock l(&mapping_mu);<br>
>><br>
>> - const uptr kMaxTextSize = 64 * 1024;<br>
>> InternalScopedString text(kMaxTextSize);<br>
>> InternalScopedBuffer<char> modules_data(kMaxNumberOfModules *<br>
>> sizeof(LoadedModule));<br>
>> @@ -66,9 +84,8 @@ void CovUpdateMapping() {<br>
>> }<br>
>><br>
>> // Do not write mapping if it is the same as the one we've wrote last<br>
>> time.<br>
>> - if (last_mapping && (internal_strcmp(last_mapping, text.data()) == 0))<br>
>> return;<br>
>> - if (!last_mapping) last_mapping = (char *)InternalAlloc(kMaxTextSize);<br>
>> - internal_strncpy(last_mapping, text.data(), kMaxTextSize);<br>
>> + if (!cached_mapping.TestAndUpdate(text.data()))<br>
>> + return;<br>
>><br>
>> int err;<br>
>> InternalScopedString tmp_path(64 +<br>
>><br>
>> Added: compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork-direct.cc<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork-direct.cc?rev=210180&view=auto" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork-direct.cc?rev=210180&view=auto</a><br>
>><br>
>> ==============================================================================<br>
>> --- compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork-direct.cc<br>
>> (added)<br>
>> +++ compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork-direct.cc<br>
>> Wed Jun 4 07:13:54 2014<br>
>> @@ -0,0 +1,38 @@<br>
>> +// RUN: %clangxx_asan -mllvm -asan-coverage=1 %s -o %t<br>
>> +// RUN: rm -rf %T/coverage-fork-direct<br>
>> +// RUN: mkdir -p %T/coverage-fork-direct && cd %T/coverage-fork-direct<br>
>> +// RUN: (ASAN_OPTIONS=coverage=1:coverage_direct=1:verbosity=1 %run %t; \<br>
>> +// RUN: %sancov rawunpack *.sancov.raw; %sancov print *.sancov) 2>&1<br>
>> +//<br>
>> +// XFAIL: android<br>
>> +<br>
>> +#include <stdio.h><br>
>> +#include <string.h><br>
>> +#include <unistd.h><br>
>> +<br>
>> +__attribute__((noinline))<br>
>> +void foo() { printf("foo\n"); }<br>
>> +<br>
>> +__attribute__((noinline))<br>
>> +void bar() { printf("bar\n"); }<br>
>> +<br>
>> +__attribute__((noinline))<br>
>> +void baz() { printf("baz\n"); }<br>
>> +<br>
>> +int main(int argc, char **argv) {<br>
>> + pid_t child_pid = fork();<br>
>> + if (child_pid == 0) {<br>
>> + fprintf(stderr, "Child PID: %d\n", getpid());<br>
>> + baz();<br>
>> + } else {<br>
>> + fprintf(stderr, "Parent PID: %d\n", getpid());<br>
>> + foo();<br>
>> + bar();<br>
>> + }<br>
>> + return 0;<br>
>> +}<br>
>> +<br>
>> +// CHECK-DAG: Child PID: [[ChildPID:[0-9]+]]<br>
>> +// CHECK-DAG: Parent PID: [[ParentPID:[0-9]+]]<br>
>> +// CHECK-DAG: read 3 PCs from {{.*}}.[[ParentPID]].sancov<br>
>> +// CHECK-DAG: read 1 PCs from {{.*}}.[[ChildPID]].sancov<br>
>><br>
>> Propchange:<br>
>> compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork-direct.cc<br>
>><br>
>> ------------------------------------------------------------------------------<br>
>> svn:eol-style = LF<br>
>><br>
>> Added: compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc?rev=210180&view=auto" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc?rev=210180&view=auto</a><br>
>><br>
>> ==============================================================================<br>
>> --- compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc (added)<br>
>> +++ compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc Wed Jun<br>
>> 4 07:13:54 2014<br>
>> @@ -0,0 +1,38 @@<br>
>> +// RUN: %clangxx_asan -mllvm -asan-coverage=1 %s -o %t<br>
>> +// RUN: export ASAN_OPTIONS=coverage=1:coverage_direct=0:verbosity=1<br>
>> +// RUN: rm -rf %T/coverage-fork<br>
>> +// RUN: mkdir -p %T/coverage-fork && cd %T/coverage-fork<br>
>> +// RUN: %run %t 2>&1 | FileCheck %s<br>
>> +//<br>
>> +// XFAIL: android<br>
>> +<br>
>> +#include <stdio.h><br>
>> +#include <string.h><br>
>> +#include <unistd.h><br>
>> +<br>
>> +__attribute__((noinline))<br>
>> +void foo() { printf("foo\n"); }<br>
>> +<br>
>> +__attribute__((noinline))<br>
>> +void bar() { printf("bar\n"); }<br>
>> +<br>
>> +__attribute__((noinline))<br>
>> +void baz() { printf("baz\n"); }<br>
>> +<br>
>> +int main(int argc, char **argv) {<br>
>> + pid_t child_pid = fork();<br>
>> + if (child_pid == 0) {<br>
>> + fprintf(stderr, "Child PID: %d\n", getpid());<br>
>> + baz();<br>
>> + } else {<br>
>> + fprintf(stderr, "Parent PID: %d\n", getpid());<br>
>> + foo();<br>
>> + bar();<br>
>> + }<br>
>> + return 0;<br>
>> +}<br>
>> +<br>
>> +// CHECK-DAG: Child PID: [[ChildPID:[0-9]+]]<br>
>> +// CHECK-DAG: [[ChildPID]].sancov: 1 PCs written<br>
>> +// CHECK-DAG: Parent PID: [[ParentPID:[0-9]+]]<br>
>> +// CHECK-DAG: [[ParentPID]].sancov: 3 PCs written<br>
>><br>
>> Propchange: compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc<br>
>><br>
>> ------------------------------------------------------------------------------<br>
>> svn:eol-style = LF<br>
>><br>
>><br>
>> _______________________________________________<br>
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>> <a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
>> <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a><br>
</div></div></blockquote></div><br></div>