From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: * X-Spam-Status: No, score=1.9 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_SOFTFAIL autolearn=no autolearn_force=no version=3.4.6 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEA12C433EF for ; Wed, 23 Mar 2022 11:16:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243780AbiCWLRi (ORCPT ); Wed, 23 Mar 2022 07:17:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241420AbiCWLRi (ORCPT ); Wed, 23 Mar 2022 07:17:38 -0400 Received: from mail-wm1-x335.google.com (mail-wm1-x335.google.com [IPv6:2a00:1450:4864:20::335]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEA7C7891E for ; Wed, 23 Mar 2022 04:16:08 -0700 (PDT) Received: by mail-wm1-x335.google.com with SMTP id r64so708798wmr.4 for ; Wed, 23 Mar 2022 04:16:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=zkUPbewTemhzOCwHb3lkPnAhb3jPaZR8hBrdZO1jAxw=; b=dm9eLiOkgk7EVxeyVWx5bpZPprcoi4ioqHj/N7TNGAeV/BHhA1rLtGCi47rxPhXZhz a/j3Po/xlU0UMWWpdetwQpxPJzMyM+yZ571vmyXWnE1jIyOl7IMB1FlwGRW1zbfNZ4N6 GhVhg4YRwVmna7GnZ6DyCdrYvlyreiArm2be5Z8ytn1qppekLFGEloQO1QeoNLpDW+Un TOJJbT1aSrGcJ/Se4TNRbbyhis1qeoHDVb1c5ZQekZpzeR60adjpfI4lYAcI+/Gynmuz yt+7w0Q9nQ+ycbkSMqbd7F9dtB53FLHDBv28lstLzcaBrxnux+danG8wvNZqgRJMIT95 ZV5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=zkUPbewTemhzOCwHb3lkPnAhb3jPaZR8hBrdZO1jAxw=; b=Ak8310zG8rcBsa+dZ7gDAsNRC0hojEeIXLEhKpPVrD5Fo8f/ZBvq/Bh1FpklMyWQk2 iiBvjygUBzd9pPsSDGEAxPz2mwRy/Fc+HKRDjzbsAmyJecnERBUEQuWYHYG670cK0Que 5hyi2NrePq/EFlC0Dzdph2hhhSVLeT9HEach1AGaVsdzD32JF1W6FciuejYLjf23ZZRt EYwOs57XkhtXn5kiT8cggq+W5Ui/MYworWb5sO97b4AUCFb/uIBIShypzJp3V47sglor xUqP5btYHfLdX4+pe30knrwv9bxCy/g49Pi4AZbqS1fmY7EG2/QUl15Cr2YYOdaMrf/d Wn4A== X-Gm-Message-State: AOAM5301XJSj2qzhDrxLizmCXdmLTSiuxCoqZCdVQTwsRbRD80mn7RYV QOK4NF/D7pIDhSDAq/kkQ4hSdtkohBlclQ== X-Google-Smtp-Source: ABdhPJz5iHNnQ4yvoWoDAi47p0/fnOXT+S0CwswEqQD05oHYOAf2pNsFM/XsM0GRczkvd/5vKrKPqg== X-Received: by 2002:a05:600c:3c8b:b0:37f:1546:40c9 with SMTP id bg11-20020a05600c3c8b00b0037f154640c9mr8516721wmb.161.1648034167245; Wed, 23 Mar 2022 04:16:07 -0700 (PDT) Received: from 127.0.0.1localhost (82-132-233-253.dab.02.net. [82.132.233.253]) by smtp.gmail.com with ESMTPSA id u7-20020a5d6da7000000b00203d9d1875bsm20107007wrs.73.2022.03.23.04.16.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Mar 2022 04:16:07 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com Subject: [PATCH for-next] io_uring: null deref in early failed ring destruction Date: Wed, 23 Mar 2022 11:14:54 +0000 Message-Id: <669d91dd881a4f7c86104b9414fa3d12477b2669.1648032632.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org [ 830.443583] Running test nop-all-sizes: [ 830.551826] BUG: kernel NULL pointer dereference, address: 00000000000000c0 [ 830.551900] RIP: 0010:io_kill_timeouts+0xc5/0xf0 [ 830.551951] Call Trace: [ 830.551958] [ 830.551970] io_ring_ctx_wait_and_kill+0xb0/0x117 [ 830.551975] io_uring_setup.cold+0x4dc/0xb97 [ 830.551990] __x64_sys_io_uring_setup+0x15/0x20 [ 830.552003] do_syscall_64+0x3b/0x80 [ 830.552011] entry_SYSCALL_64_after_hwframe+0x44/0xae Apparently, not all io_commi_cqring() guarding was useless, some were protecting against cases where we call io_ring_ctx_wait_and_kill() for a ring failed early during creation. This particular one points to (gdb) l *(io_kill_timeouts+0xc5) 0xffffffff81b26b19 is in io_kill_timeouts (fs/io_uring.c:1813). 1808 } 1809 1810 static inline void io_commit_cqring(struct io_ring_ctx *ctx) 1811 { 1812 /* order cqe stores with ring update */ 1813 smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail); 1814 } A better way to handle the problem is to not get into the request cancellation paths for when we don't have ctx->rings allocated. Fixes: c9be622494c01 ("io_uring: remove extra ifs around io_commit_cqring") Signed-off-by: Pavel Begunkov --- fs/io_uring.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 594ed8bc4585..6ad81d39d81e 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -10309,11 +10309,13 @@ static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) io_unregister_personality(ctx, index); mutex_unlock(&ctx->uring_lock); - io_kill_timeouts(ctx, NULL, true); - io_poll_remove_all(ctx, NULL, true); - - /* if we failed setting up the ctx, we might not have any rings */ - io_iopoll_try_reap_events(ctx); + /* failed during ring init, it couldn't have issued any requests */ + if (ctx->rings) { + io_kill_timeouts(ctx, NULL, true); + io_poll_remove_all(ctx, NULL, true); + /* if we failed setting up the ctx, we might not have any rings */ + io_iopoll_try_reap_events(ctx); + } INIT_WORK(&ctx->exit_work, io_ring_exit_work); /* @@ -10405,6 +10407,10 @@ static __cold void io_uring_try_cancel_requests(struct io_ring_ctx *ctx, struct io_task_cancel cancel = { .task = task, .all = cancel_all, }; struct io_uring_task *tctx = task ? task->io_uring : NULL; + /* failed during ring init, it couldn't have issued any requests */ + if (!ctx->rings) + return; + while (1) { enum io_wq_cancel cret; bool ret = false; -- 2.35.1