[compiler-rt] r287632 - tsan: switch libignore from /proc/self/maps to dl_iterate_phdr
Dmitry Vyukov via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 22 03:19:38 PST 2016
287634 should fix it
On Tue, Nov 22, 2016 at 12:17 PM, Dmitry Vyukov <dvyukov at google.com> wrote:
> Looking
>
> Thanks
>
> On Tue, Nov 22, 2016 at 12:13 PM, Diana Picus <diana.picus at linaro.org> wrote:
>> Hi Dmitry,
>>
>> Can you please have a look at this failure:
>> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-42vma/builds/1198
>> ?
>>
>> Thanks,
>> Diana
>>
>> On 22 November 2016 at 11:49, Dmitry Vyukov via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>>> Author: dvyukov
>>> Date: Tue Nov 22 03:49:11 2016
>>> New Revision: 287632
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=287632&view=rev
>>> Log:
>>> tsan: switch libignore from /proc/self/maps to dl_iterate_phdr
>>>
>>> /proc/self/maps can't be read atomically, this leads to episodic
>>> crashes in libignore as it thinks that a module is loaded twice.
>>> See the new test for an example.
>>> dl_iterate_phdr does not have this problem.
>>> Switch libignore to dl_iterate_phdr.
>>>
>>>
>>> Added:
>>> compiler-rt/trunk/test/tsan/ignore_lib5.cc
>>> compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp
>>> Modified:
>>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc
>>>
>>> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc
>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc?rev=287632&r1=287631&r2=287632&view=diff
>>> ==============================================================================
>>> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc (original)
>>> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc Tue Nov 22 03:49:11 2016
>>> @@ -50,23 +50,23 @@ void LibIgnore::OnLibraryLoaded(const ch
>>> }
>>>
>>> // Scan suppressions list and find newly loaded and unloaded libraries.
>>> - MemoryMappingLayout proc_maps(/*cache_enabled*/false);
>>> - InternalScopedString module(kMaxPathLength);
>>> + ListOfModules modules;
>>> + modules.init();
>>> for (uptr i = 0; i < count_; i++) {
>>> Lib *lib = &libs_[i];
>>> bool loaded = false;
>>> - proc_maps.Reset();
>>> - uptr b, e, off, prot;
>>> - while (proc_maps.Next(&b, &e, &off, module.data(), module.size(), &prot)) {
>>> - if ((prot & MemoryMappingLayout::kProtectionExecute) == 0)
>>> - continue;
>>> - if (TemplateMatch(lib->templ, module.data()) ||
>>> - (lib->real_name &&
>>> - internal_strcmp(lib->real_name, module.data()) == 0)) {
>>> + for (const auto &mod : modules) {
>>> + for (const auto &range : mod.ranges()) {
>>> + if (!range.executable)
>>> + continue;
>>> + if (!TemplateMatch(lib->templ, mod.full_name()) &&
>>> + !(lib->real_name &&
>>> + internal_strcmp(lib->real_name, mod.full_name()) == 0))
>>> + continue;
>>> if (loaded) {
>>> Report("%s: called_from_lib suppression '%s' is matched against"
>>> " 2 libraries: '%s' and '%s'\n",
>>> - SanitizerToolName, lib->templ, lib->name, module.data());
>>> + SanitizerToolName, lib->templ, lib->name, mod.full_name());
>>> Die();
>>> }
>>> loaded = true;
>>> @@ -75,13 +75,14 @@ void LibIgnore::OnLibraryLoaded(const ch
>>> VReport(1,
>>> "Matched called_from_lib suppression '%s' against library"
>>> " '%s'\n",
>>> - lib->templ, module.data());
>>> + lib->templ, mod.full_name());
>>> lib->loaded = true;
>>> - lib->name = internal_strdup(module.data());
>>> + lib->name = internal_strdup(mod.full_name());
>>> const uptr idx = atomic_load(&loaded_count_, memory_order_relaxed);
>>> - code_ranges_[idx].begin = b;
>>> - code_ranges_[idx].end = e;
>>> + code_ranges_[idx].begin = range.beg;
>>> + code_ranges_[idx].end = range.end;
>>> atomic_store(&loaded_count_, idx + 1, memory_order_release);
>>> + break;
>>> }
>>> }
>>> if (lib->loaded && !loaded) {
>>>
>>> Added: compiler-rt/trunk/test/tsan/ignore_lib5.cc
>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/tsan/ignore_lib5.cc?rev=287632&view=auto
>>> ==============================================================================
>>> --- compiler-rt/trunk/test/tsan/ignore_lib5.cc (added)
>>> +++ compiler-rt/trunk/test/tsan/ignore_lib5.cc Tue Nov 22 03:49:11 2016
>>> @@ -0,0 +1,65 @@
>>> +// RUN: %clangxx_tsan -O1 %s -DLIB -fPIC -fno-sanitize=thread -shared -o %T/libignore_lib1.so
>>> +// RUN: %clangxx_tsan -O1 %s -o %t
>>> +// RUN: echo running w/o suppressions:
>>> +// RUN: %deflake %run %t | FileCheck %s --check-prefix=CHECK-NOSUPP
>>> +// RUN: echo running with suppressions:
>>> +// RUN: %env_tsan_opts=suppressions='%s.supp' %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-WITHSUPP
>>> +
>>> +// REQUIRES: stable-runtime
>>> +
>>> +// Previously the test episodically failed with:
>>> +// ThreadSanitizer: called_from_lib suppression '/libignore_lib1.so$' is
>>> +// matched against 2 libraries: '/libignore_lib1.so' and '/libignore_lib1.so'
>>> +// This was caused by non-atomicity of reading of /proc/self/maps.
>>> +
>>> +#ifndef LIB
>>> +
>>> +#include <dlfcn.h>
>>> +#include <sys/mman.h>
>>> +#include <stdlib.h>
>>> +#include <stdio.h>
>>> +#include <errno.h>
>>> +#include <libgen.h>
>>> +#include <string>
>>> +#include "test.h"
>>> +
>>> +void *thr(void *arg) {
>>> + // This thread creates lots of separate mappings in /proc/self/maps before
>>> + // the ignored library.
>>> + for (int i = 0; i < 10000; i++) {
>>> + if (i == 5000)
>>> + barrier_wait(&barrier);
>>> + mmap(0, 4096, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE | MAP_32BIT, -1 , 0);
>>> + mmap(0, 4096, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_32BIT, -1 , 0);
>>> + }
>>> + return 0;
>>> +}
>>> +
>>> +int main(int argc, char **argv) {
>>> + barrier_init(&barrier, 2);
>>> + pthread_t th;
>>> + pthread_create(&th, 0, thr, 0);
>>> + barrier_wait(&barrier);
>>> + std::string lib = std::string(dirname(argv[0])) + "/libignore_lib1.so";
>>> + void *h = dlopen(lib.c_str(), RTLD_GLOBAL | RTLD_NOW);
>>> + if (h == 0)
>>> + exit(printf("failed to load the library (%d)\n", errno));
>>> + void (*f)() = (void(*)())dlsym(h, "libfunc");
>>> + if (f == 0)
>>> + exit(printf("failed to find the func (%d)\n", errno));
>>> + pthread_join(th, 0);
>>> + f();
>>> +}
>>> +
>>> +#else // #ifdef LIB
>>> +
>>> +#include "ignore_lib_lib.h"
>>> +
>>> +#endif // #ifdef LIB
>>> +
>>> +// CHECK-NOSUPP: WARNING: ThreadSanitizer: data race
>>> +// CHECK-NOSUPP: OK
>>> +
>>> +// CHECK-WITHSUPP-NOT: WARNING: ThreadSanitizer: data race
>>> +// CHECK-WITHSUPP: OK
>>> +
>>>
>>> Added: compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp
>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp?rev=287632&view=auto
>>> ==============================================================================
>>> --- compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp (added)
>>> +++ compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp Tue Nov 22 03:49:11 2016
>>> @@ -0,0 +1,2 @@
>>> +called_from_lib:/libignore_lib1.so$
>>> +
>>>
>>>
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