f1b6bd403d
Summary: Do not grab the allocator lock before calling dl_iterate_phdr. This may cause a lock order inversion with (valid) user code that uses malloc inside a dl_iterate_phdr callback. Reviewers: vitalybuka, hctim Subscribers: jfb, #sanitizers, llvm-commits Tags: #sanitizers, #llvm Differential Revision: https://reviews.llvm.org/D67738 llvm-svn: 372348
53 lines
1.1 KiB
C++
53 lines
1.1 KiB
C++
// Regression test for a deadlock in leak detection,
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// where lsan would call dl_iterate_phdr while holding the allocator lock.
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// RUN: %clangxx_lsan %s -o %t && %run %t
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#include <link.h>
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#include <mutex>
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#include <stdlib.h>
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#include <thread>
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#include <unistd.h>
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std::mutex in, out;
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int Callback(struct dl_phdr_info *info, size_t size, void *data) {
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for (int step = 0; step < 50; ++step) {
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void *p[1000];
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for (int i = 0; i < 1000; ++i)
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p[i] = malloc(10 * i);
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if (step == 0)
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in.unlock();
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for (int i = 0; i < 1000; ++i)
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free(p[i]);
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}
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out.unlock();
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return 1; // just once
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}
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void Watchdog() {
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// This is just a fail-safe to turn a deadlock (in case the bug reappears)
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// into a (slow) test failure.
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usleep(10000000);
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if (!out.try_lock()) {
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write(2, "DEADLOCK\n", 9);
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exit(1);
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}
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}
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int main() {
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in.lock();
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out.lock();
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std::thread t([] { dl_iterate_phdr(Callback, nullptr); });
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t.detach();
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std::thread w(Watchdog);
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w.detach();
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// Wait for the malloc thread to preheat, then start leak detection (on exit)
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in.lock();
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return 0;
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}
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