From patchwork Tue Jan 26 11:17:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 371357 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62C75C433DB for ; Tue, 26 Jan 2021 12:07:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 33ECD2311F for ; Tue, 26 Jan 2021 12:07:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392347AbhAZMHT (ORCPT ); Tue, 26 Jan 2021 07:07:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392343AbhAZLW6 (ORCPT ); Tue, 26 Jan 2021 06:22:58 -0500 Received: from mail-ej1-x62f.google.com (mail-ej1-x62f.google.com [IPv6:2a00:1450:4864:20::62f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 095E7C061793 for ; Tue, 26 Jan 2021 03:21:09 -0800 (PST) Received: by mail-ej1-x62f.google.com with SMTP id r12so22373720ejb.9 for ; Tue, 26 Jan 2021 03:21:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=43tk6v3IVG2/MesRm+z+pQpDZTwX1/vxi63pQJvRipg=; b=CQYgS/cvzzkk16lLeYHNEzPzrTPh29AP2JhvgDOTWaR0aFt+yNBYM4uKPu7yusFhBO aEVodqe6CzD4LH646HbYc6SP9yqCxYKVmCQPOU+a/S+S91npBw2OVdAS3Jspt2Ggv6Zs NPuhDPXjwFFV6qxHG8NL2Guu0aY1l8DtoFpizDC0TUyt+VckqoZ4uaIYwWuvz84A4Idm OG2QOR5g2EMXBFrJuNssPdOa2zLtzQB/Q0xwKL4nZylkFEcvamRk66SL5WQ8mLBuiC7R sjKYLVLiQOWneCDVE/hwls+y9Be0WG4YTjleiHzzlQKxDvW9hwOvqb2gz9ex/9KZq90A 8CIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=43tk6v3IVG2/MesRm+z+pQpDZTwX1/vxi63pQJvRipg=; b=JTJ5GDO358b0In/KX84dim1gC/+AAJ0+aR0lNkVQglLccMq8pzp4bSC1ss8syOjeP5 Uz+sL2lIl6r+bB3zKiVFkmRECsBjdNhFHiNlkG2RCxaxiQ0G63lNlOuHQMH/t9JF2akO cX0wHLQob9s8TpNix8ABC7uyPJg3JuCj4Bg5piv8KGm33b+kBNrAFK+sOZRJbfbyiUNG fjt367bI5/jc6tVtTlLjdY1Pz6yFo3Qp1dtB67gPU79el+94052rBsnm2+TxgyXamvbw yjoKHPIhp+DUchvssEOffrT+3KyI3Hmd4Bk9ncHwD8ndeJhEvIGmoOh0Y7TdPFIcaNIp hLUw== X-Gm-Message-State: AOAM533Sn6ToAfdpc++M64Wyt6kGxRDUzrCOuhI+aRQCd/t2tDPFlB0q fwvrbJs5zhsHYcNCyRfd8X+gdJOz0JE65g== X-Google-Smtp-Source: ABdhPJwl3NOhtSsb7q0O6s0l9JbSsho+0RLToUKXR4ut5Y9mHVY288/kouyYyhqFIPeAyPCt/5N5Xg== X-Received: by 2002:a17:906:b2d5:: with SMTP id cf21mr3164578ejb.387.1611660067623; Tue, 26 Jan 2021 03:21:07 -0800 (PST) Received: from localhost.localdomain ([148.252.129.161]) by smtp.gmail.com with ESMTPSA id o17sm12167128edr.17.2021.01.26.03.21.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Jan 2021 03:21:07 -0800 (PST) From: Pavel Begunkov To: stable@vger.kernel.org Cc: Jens Axboe , syzbot+91ca3f25bd7f795f019c@syzkaller.appspotmail.com Subject: [PATCH stable 10/11] io_uring: dont kill fasync under completion_lock Date: Tue, 26 Jan 2021 11:17:09 +0000 Message-Id: <41777a0d41ba61011c7ef96d44de36f37ec5e8ea.1611659564.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 4aa84f2ffa81f71e15e5cffc2cc6090dbee78f8e ] CPU0 CPU1 ---- ---- lock(&new->fa_lock); local_irq_disable(); lock(&ctx->completion_lock); lock(&new->fa_lock); lock(&ctx->completion_lock); *** DEADLOCK *** Move kill_fasync() out of io_commit_cqring() to io_cqring_ev_posted(), so it doesn't hold completion_lock while doing it. That saves from the reported deadlock, and it's just nice to shorten the locking time and untangle nested locks (compl_lock -> wq_head::lock). Cc: stable@vger.kernel.org # 5.5+ Reported-by: syzbot+91ca3f25bd7f795f019c@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 5ead8b6aeda2..1c5d71829bf5 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1213,11 +1213,6 @@ static void __io_commit_cqring(struct io_ring_ctx *ctx) /* order cqe stores with ring update */ smp_store_release(&rings->cq.tail, ctx->cached_cq_tail); - - if (wq_has_sleeper(&ctx->cq_wait)) { - wake_up_interruptible(&ctx->cq_wait); - kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); - } } static void io_put_identity(struct io_uring_task *tctx, struct io_kiocb *req) @@ -1584,6 +1579,10 @@ static inline bool io_should_trigger_evfd(struct io_ring_ctx *ctx) static void io_cqring_ev_posted(struct io_ring_ctx *ctx) { + if (wq_has_sleeper(&ctx->cq_wait)) { + wake_up_interruptible(&ctx->cq_wait); + kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); + } if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); if (ctx->sq_data && waitqueue_active(&ctx->sq_data->wait))