[英]C++ bad_alloc exception on future.get
我的 C++ 程序退出时出现 bad_alloc 异常。 我试图找到原因,但不太知道如何调试此类异常。
到目前为止,我在调试模式下编译了程序,使用 gdb 运行它并在抛出异常之前设置断点( b 'std::bad_alloc::bad_alloc()'
)。
抛出异常后,我检查了堆栈( bt
),显示如下:
(gdb) bt
#0 0x00007ffff752f1f7 in raise () from /lib64/libc.so.6
#1 0x00007ffff75308e8 in abort () from /lib64/libc.so.6
#2 0x00007ffff7f0a7fd in __gnu_cxx::__verbose_terminate_handler () at ../../../../libstdc++-v3/libsupc++/vterminate.cc:95
#3 0x00007ffff7f08876 in __cxxabiv1::__terminate (handler=<optimized out>) at ../../../../libstdc++-v3/libsupc++/eh_terminate.cc:47
#4 0x00007ffff7f088c1 in std::terminate () at ../../../../libstdc++-v3/libsupc++/eh_terminate.cc:57
#5 0x00007ffff7f0886a in std::rethrow_exception (ep=...) at ../../../../libstdc++-v3/libsupc++/eh_ptr.cc:259
#6 0x0000000000419001 in std::__basic_future<void>::_M_get_result (this=0x55b9a0)
at /soft/EB_repo/devel/programs/foss/2016b/GCCcore/5.4.0/include/c++/5.4.0/future:683
#7 0x0000000000416da6 in std::future<void>::get (this=0x55b9a0) at /soft/EB_repo/devel/programs/foss/2016b/GCCcore/5.4.0/include/c++/5.4.0/future:846
#8 0x00000000004d152f in cluster_reads (reads=..., kmer_size=14, t_s=0.10000000000000001, t_v=500, bv_threshold=0.40000000000000002,
min_bv_threshold=0.20000000000000001, bv_falloff=0.050000000000000003, min_reads_cluster=0, n_threads=8) at cluster.cpp:81
#9 0x000000000040910b in main (argc=8, argv=0x7fffffffc028) at main.cpp:106
正如您在 #7 中看到的,获取 std::future 时抛出异常? 这是 cluster_reads (#8) 中崩溃的一段代码(我用箭头标记了第 81 行)。
std::vector<std::vector<kmer_t>> kmers(reads.size());
std::vector<std::vector<kmer_t>> rev_kmers(reads.size());
std::vector<kmer_bv_t> bv_kmers(reads.size());
std::vector<kmer_bv_t> rev_bv_kmers(reads.size());
std::vector<std::future<void>> tasks;
for (int t = 0; t < n_threads; ++t) {
tasks.emplace_back(std::async(std::launch::async, [t, &reads, n_threads, kmer_size, &kmers, &rev_kmers, &bv_kmers, &rev_bv_kmers] {
for (int i = t; i < reads.size(); i+=n_threads) {
read_kmers_t k1 = extract_kmers_from_read(reads[i].seq, kmer_size);
kmers[i] = k1.list_forward;
rev_kmers[i] = k1.list_reverse;
bv_kmers[i] = k1.bv_forward;
rev_bv_kmers[i] = k1.bv_reverse;
}
}));
}
for (auto &&task : tasks) {
task.get(); <------------------- line 81
}
我怎样才能进一步调试这个问题? 我对 gdb 很陌生。 关于可能导致 bad_alloc 异常的任何想法?
这似乎是在其中一个线程中抛出了std::bad_alloc
,后来被task.get()
您错误地认为这是异常的来源)。 这是来自future::get()
cppreference的引用
异常如果异常存储在未来引用的共享状态中(例如通过调用
std::promise::set_exception())
那么该异常将被抛出。
由于在以下位置分配std::vector<kmer_t>
可能会发生这种情况:
read_kmers_t k1 = extract_kmers_from_read(reads[i].seq, kmer_size);
后来在:
kmers[i] = k1.list_forward;
从变量的名称来看,我假设您正在阅读基因组数据库,如果您不小心,它可能会很大并耗尽您的记忆。
要捕捉抛出异常的确切时刻,您应该告诉 gdb:
(gdb) catch throw
这将在引发原始异常的地方停止执行。
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