From patchwork Wed Sep 7 16:35:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shigeru Yoshida X-Patchwork-Id: 12969235 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26E28C54EE9 for ; Wed, 7 Sep 2022 16:35:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229459AbiIGQfU (ORCPT ); Wed, 7 Sep 2022 12:35:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229487AbiIGQfS (ORCPT ); Wed, 7 Sep 2022 12:35:18 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7765C140BD for ; Wed, 7 Sep 2022 09:35:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1662568516; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=A0VSNh+UywAONPBjLpCLWLZqP5s9DGWDr3ehS/v+q+A=; b=RSAofNuez/18iBp02OijoJtRhRETYtgPwV1jvyzwUPcLNcdGTTrnJDIC81KNvrVLyK8RRZ Zm/hYDqCp+/Ba5xXR9ZUg2dS+cwRAyEqtkr7KeXjEOKejTpRIMfLuJkXjmrnFbELTx/H6h uUL5mUzr51gHcQWvwEeiBMH2aOzIyxA= Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-8-D7R2TR9zMhSDkU-eNznKBg-1; Wed, 07 Sep 2022 12:35:15 -0400 X-MC-Unique: D7R2TR9zMhSDkU-eNznKBg-1 Received: by mail-pg1-f197.google.com with SMTP id k16-20020a635a50000000b0042986056df6so7687649pgm.2 for ; Wed, 07 Sep 2022 09:35:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date; bh=A0VSNh+UywAONPBjLpCLWLZqP5s9DGWDr3ehS/v+q+A=; b=10DqIjhIk5dqkf5s1AJBcUhhn1Y9YCjccuMZjnt+hI07K+OwACE7ykoQyTNH1TEGkD c2ZUqLcsd/Oar8gon5uOR6p38uFpic6qRN7pearka0JraOPTL3X4z5tGIXv5Klqx9jYI FSZIjKqiUnh3Io11ZGszuPPghPsyvW9bg/st5Bvs0rFhzyzQzo1HaKvJDN1O7uskQseb Ccr1CTFHZkcLIWP2R0gT7h9qnkmJQg3uOqOFEw1apvwaRski78W6CdpHzxLspp0njdXM fsCSvEObCcByNkPaoTWaxz1hAB+DPGxICttdBGvGQj+UctwMf2jm/CFf26sO3zIiVWHz G9tw== X-Gm-Message-State: ACgBeo0owGmaPP4S0HQ3xclvsH9L5qYPvmdf1mhEHolfnx0PZWY/34uI mBBXx5n5OzoDqRoN3R6OXoAH2pYp+uaPcDe0KansB9qpdOjVtwQUXXTrpFps2kVe+Dm/F8yW0Kn B46sqeUJfI9z3MSxMa2DOdpw= X-Received: by 2002:a17:902:9b85:b0:16e:cc02:b9b2 with SMTP id y5-20020a1709029b8500b0016ecc02b9b2mr4538454plp.74.1662568514415; Wed, 07 Sep 2022 09:35:14 -0700 (PDT) X-Google-Smtp-Source: AA6agR7r/x7CdhyIi+Ws6YtHvtEtvjDAJ5wS2GD6N2EGK8KrkbtXG4v7M/3xt+UtWy169uWDtkAVJg== X-Received: by 2002:a17:902:9b85:b0:16e:cc02:b9b2 with SMTP id y5-20020a1709029b8500b0016ecc02b9b2mr4538435plp.74.1662568514147; Wed, 07 Sep 2022 09:35:14 -0700 (PDT) Received: from xps13.. ([240d:1a:c0d:9f00:4f2f:926a:23dd:8588]) by smtp.gmail.com with ESMTPSA id e22-20020aa79816000000b00537e328bc11sm12688689pfl.31.2022.09.07.09.35.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Sep 2022 09:35:13 -0700 (PDT) From: Shigeru Yoshida To: josef@toxicpanda.com, axboe@kernel.dk Cc: linux-block@vger.kernel.org, nbd@other.debian.org, linux-kernel@vger.kernel.org, Shigeru Yoshida , syzbot+38e6c55d4969a14c1534@syzkaller.appspotmail.com Subject: [PATCH] nbd: Fix hung when signal interrupts nbd_start_device_ioctl() Date: Thu, 8 Sep 2022 01:35:02 +0900 Message-Id: <20220907163502.577561-1-syoshida@redhat.com> X-Mailer: git-send-email 2.37.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org syzbot reported hung task [1]. The following program is a simplified version of the reproducer: int main(void) { int sv[2], fd; if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) < 0) return 1; if ((fd = open("/dev/nbd0", 0)) < 0) return 1; if (ioctl(fd, NBD_SET_SIZE_BLOCKS, 0x81) < 0) return 1; if (ioctl(fd, NBD_SET_SOCK, sv[0]) < 0) return 1; if (ioctl(fd, NBD_DO_IT) < 0) return 1; return 0; } When signal interrupt nbd_start_device_ioctl() waiting the condition atomic_read(&config->recv_threads) == 0, the task can hung because it waits the completion of the inflight IOs. This patch fixes the issue by clearing queue, not just shutdown, when signal interrupt nbd_start_device_ioctl(). Link: https://syzkaller.appspot.com/bug?id=7d89a3ffacd2b83fdd39549bc4d8e0a89ef21239 [1] Reported-by: syzbot+38e6c55d4969a14c1534@syzkaller.appspotmail.com Signed-off-by: Shigeru Yoshida Reviewed-by: Josef Bacik --- drivers/block/nbd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 2a709daefbc4..2a2a1d996a57 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1413,10 +1413,12 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd) mutex_unlock(&nbd->config_lock); ret = wait_event_interruptible(config->recv_wq, atomic_read(&config->recv_threads) == 0); - if (ret) + if (ret) { sock_shutdown(nbd); - flush_workqueue(nbd->recv_workq); + nbd_clear_que(nbd); + } + flush_workqueue(nbd->recv_workq); mutex_lock(&nbd->config_lock); nbd_bdev_reset(nbd); /* user requested, ignore socket errors */