Hi Amit, Your analysis and fix looks correct to me that the hotplug processing may run on a single core but other operations may cause race condition. Will you submit a patch to Gerrit for this issue? It may be better to post an issue to Github together. Thanks, Shuhei ________________________________ 差出人: SPDK <spdk-bounces(a)lists.01.org&gt; が Kumar, Amit1 <amit1.kumar(a)intel.com&gt; の代理で送信 送信日時: 2019年6月24日 21:02 宛先: Storage Performance Development Kit 件名: [!][SPDK] Race condition in drive hot plug being handled twice. Hi, Looks like there is a race condition while handling the case to avoid drive hot plug twice in below SPDK code, bdev_nvme.c - Existing code - pthread_mutex_lock(&g_bdev_nvme_mutex); TAILQ_FOREACH(nvme_bdev_ctrlr, &g_nvme_bdev_ctrlrs, tailq) { if (nvme_bdev_ctrlr->ctrlr == ctrlr) { /* The controller's destruction was already started */ if (nvme_bdev_ctrlr->destruct) { pthread_mutex_unlock(&g_bdev_nvme_mutex); return; } pthread_mutex_unlock(&g_bdev_nvme_mutex); for (i = 0; i < nvme_bdev_ctrlr->num_ns; i++) { uint32_t nsid = i + 1; nvme_bdev = &nvme_bdev_ctrlr->bdevs[nsid - 1]; if (nvme_bdev->active) { assert(nvme_bdev->id == nsid); spdk_bdev_unregister(&nvme_bdev->disk, NULL, NULL); } } pthread_mutex_lock(&g_bdev_nvme_mutex); nvme_bdev_ctrlr->destruct = true; I think "destruct" variable needs to be set with in first block of mutex lock before calling "spdk_bdev_unregister". pthread_mutex_lock(&g_bdev_nvme_mutex); TAILQ_FOREACH(nvme_bdev_ctrlr, &g_nvme_bdev_ctrlrs, tailq) { if (nvme_bdev_ctrlr->ctrlr == ctrlr) { /* The controller's destruction was already started */ if (nvme_bdev_ctrlr->destruct) { pthread_mutex_unlock(&g_bdev_nvme_mutex); return; } nvme_bdev_ctrlr->destruct = true; --> this should be set before releasing the lock. pthread_mutex_unlock(&g_bdev_nvme_mutex); Please let me know your inputs on this. Thanks, Amit _______________________________________________ SPDK mailing list SPDK(a)lists.01.org https://clicktime.symantec.com/35huGd19KJkhRntCNN94w3g7Vc?u=https%3A%2F%2...