62 lines
2.0 KiB
C++
62 lines
2.0 KiB
C++
// Copyright 2022 The Chromium Authors
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/allocator/dispatcher/reentry_guard.h"
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#include "base/check.h"
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#include "base/compiler_specific.h"
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#include "base/debug/crash_logging.h"
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#include "base/strings/string_number_conversions.h"
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#include "build/build_config.h"
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#if BUILDFLAG(IS_APPLE) || BUILDFLAG(IS_ANDROID)
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#include <pthread.h>
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#endif
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namespace base::allocator::dispatcher {
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#if BUILDFLAG(IS_APPLE) || BUILDFLAG(IS_ANDROID)
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// pthread_key_t has different signedness on Mac and Android. Store the null
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// value in a strongly-typed constant to avoid "comparison of integers of
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// different signs" warnings when comparing with 0.
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constexpr pthread_key_t kNullKey = 0;
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pthread_key_t ReentryGuard::entered_key_ = kNullKey;
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void ReentryGuard::InitTLSSlot() {
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if (entered_key_ == kNullKey) {
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int error = pthread_key_create(&entered_key_, nullptr);
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CHECK(!error);
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// Touch the TLS slot immediately to force any allocations.
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// TODO(https://crbug.com/1411454): Use this technique to avoid allocations
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// in PoissonAllocationSampler::ScopedMuteThreadSamples, which will make
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// ReentryGuard redundant.
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pthread_setspecific(entered_key_, nullptr);
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}
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DCHECK_NE(entered_key_, kNullKey);
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}
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#else
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void ReentryGuard::InitTLSSlot() {}
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#endif
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void ReentryGuard::RecordTLSSlotToCrashKey() {
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// Record the key in crash dumps to detect when it's higher than 32
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// (PTHREAD_KEY_2NDLEVEL_SIZE).
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// TODO(crbug.com/1411454): Remove this after diagnosing reentry crashes.
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static auto* const crash_key = base::debug::AllocateCrashKeyString(
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"reentry_guard_tls_slot", base::debug::CrashKeySize::Size32);
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#if BUILDFLAG(IS_APPLE) || BUILDFLAG(IS_ANDROID)
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base::debug::SetCrashKeyString(crash_key, base::NumberToString(entered_key_));
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#else
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base::debug::SetCrashKeyString(crash_key, "unused");
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#endif
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}
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} // namespace base::allocator::dispatcher
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