Hi, developers, thank you for your checking. It seems there is a (potential) deadlock bug in the below code. The function extract_worker_thread_func is not thread-safe, because there is a cyclic acquisition order between the ctxt->mutex and entry->mutex.
{color:#DE350B}extract_worker_thread_func(void *arg)
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{
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while (1) {
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pthread_mutex_lock(ctxt->mutex);
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...;
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pthread_mutex_lock(&entry->mutex); //ctxt->mutex-->entry->mutex
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pthread_mutex_unlock(ctxt->mutex);
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...;
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if (chunk.type == XB_CHUNK_TYPE_EOF) {
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pthread_mutex_lock(ctxt->mutex); // entry->mutex-> ctxt->mutex
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pthread_mutex_unlock(&entry->mutex);
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my_hash_delete(ctxt->filehash, (uchar *) entry);
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pthread_mutex_unlock(ctxt->mutex);
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continue;
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}
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...;
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pthread_mutex_unlock(&entry->mutex);
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}
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}{color}
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https://github.com/MariaDB/server/blob/76f4a78ba2639b5abd01a88b24a3c509c11530ce/extra/mariabackup/xbstream.cc#L381-L478
Major 