From patchwork Sat Oct 22 07:29:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 7722 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:4242:0:0:0:0:0 with SMTP id s2csp1109918wrr; Sat, 22 Oct 2022 01:50:35 -0700 (PDT) X-Google-Smtp-Source: AMsMyM6b3VLDBoF7rXbc73ZDgswPxqSD6PMmwlDgD60Hb3hGHkAKSUlWmqdyPv8Qgc3hlZomzTtf X-Received: by 2002:a05:6402:528a:b0:454:8613:6560 with SMTP id en10-20020a056402528a00b0045486136560mr22177745edb.252.1666428635456; Sat, 22 Oct 2022 01:50:35 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1666428635; cv=none; d=google.com; s=arc-20160816; b=FRjD9Eqgah1/kaGVcZbJmQLsh4gi8ItPcabNx+CJSrquSfBgF2wt2kOTAJKOBiT2zX OJKMnBBUoVuxxnN4nknWaJ994IF7ihymLPPY5aweo+Y6hkV+bjWNyMYJpteU0d2YIbwq OG/m4/DVqHbEcR0YK+Z2B2t+kcrrjIwJKUo4tetWDHWYKaZJXBcBkMHox0otJayq2kPT 0472i1cxLsPg8uQeWulJTFPa37nNP8Qengcn3csDPD+nnMztbnsHXVlOEHvrHJ+wFcMa GZxGHdJvtH5aOerMyeS4hx9YZ8EUa0wpAcm+2VFluTslly4XcmhFd8EYPTzSyDIsGQvB CLxA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=+yMAdfvg47D5284nSl89wNn8LNC3+9uRMIfc5Wycjrg=; b=fVZlZkiTa5LDG3BkhWowkbk+AJoIC3xxUxFTlbxhef35JgR8D0oZbq2kpTgnevRpsS BXW6XbtyKtpdvnX5NMkZtOKhsFxNrEGhRMA/rphWn9Ds7x2OGHt0HK2VCcwLQhwsrBYk 9xuRnzCY7mMkj/VCJBmyelgSb3FzgrMs4M/nsaE8u0lYG9mKQ+UUt6amdgYkLBAsGWp4 nLr96lF0KhCuYIKvWzra8ZO4fhoxUWYJg1UuUhLDlpC1FcQO7WxJdskwDEAN1ZpE5rAM g2OVbUXBK46IviYWieKp4FbPRg0/pjTLuAgT8WM0nxX7XlFvi/3wwv+Gk++6AqTqm/7X qMNA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=SAROwZfc; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id d26-20020a056402401a00b0045fb9d7dd25si7679937eda.298.2022.10.22.01.50.11; Sat, 22 Oct 2022 01:50:35 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=SAROwZfc; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234643AbiJVIsv (ORCPT + 99 others); Sat, 22 Oct 2022 04:48:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234846AbiJVIqO (ORCPT ); Sat, 22 Oct 2022 04:46:14 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D9C94B9BD; Sat, 22 Oct 2022 01:09:49 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A8BF560B81; Sat, 22 Oct 2022 08:06:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BA13C433C1; Sat, 22 Oct 2022 08:06:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666425964; bh=65OQIF2TZJuQiwOc2TEY9Dne2mpIqXtPwuvl01EMQCs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SAROwZfccZX3vB688CGoiyowRrBGHgG5QBDk8MSWABZ5IOx1WHMcByBmuCqQ3Q5gW k9ySylwbNJD9hn5TR4y9XQMidbqYzXraEwAds06cI5fuZF8/d3UdxoDoh2gK+3UFUo 9LMmbHtTUIq46zvvAO9qBQH3tWeM7hDIELXonc3w= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dylan Yudaken , Jens Axboe , Sasha Levin Subject: [PATCH 5.19 673/717] eventfd: guard wake_up in eventfd fs calls as well Date: Sat, 22 Oct 2022 09:29:12 +0200 Message-Id: <20221022072528.210304370@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221022072415.034382448@linuxfoundation.org> References: <20221022072415.034382448@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 X-Spam-Status: No, score=-7.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1747377073019909643?= X-GMAIL-MSGID: =?utf-8?q?1747377073019909643?= From: Dylan Yudaken [ Upstream commit 9f0deaa12d832f488500a5afe9b912e9b3cfc432 ] Guard wakeups that the user can trigger, and that may end up triggering a call back into eventfd_signal. This is in addition to the current approach that only guards in eventfd_signal. Rename in_eventfd_signal -> in_eventfd at the same time to reflect this. Without this there would be a deadlock in the following code using libaio: int main() { struct io_context *ctx = NULL; struct iocb iocb; struct iocb *iocbs[] = { &iocb }; int evfd; uint64_t val = 1; evfd = eventfd(0, EFD_CLOEXEC); assert(!io_setup(2, &ctx)); io_prep_poll(&iocb, evfd, POLLIN); io_set_eventfd(&iocb, evfd); assert(1 == io_submit(ctx, 1, iocbs)); write(evfd, &val, 8); } Signed-off-by: Dylan Yudaken Reviewed-by: Jens Axboe Link: https://lore.kernel.org/r/20220816135959.1490641-1-dylany@fb.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- fs/eventfd.c | 10 +++++++--- include/linux/eventfd.h | 2 +- include/linux/sched.h | 2 +- 3 files changed, 9 insertions(+), 5 deletions(-) diff --git a/fs/eventfd.c b/fs/eventfd.c index 3627dd7d25db..c0ffee99ad23 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -69,17 +69,17 @@ __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n) * it returns false, the eventfd_signal() call should be deferred to a * safe context. */ - if (WARN_ON_ONCE(current->in_eventfd_signal)) + if (WARN_ON_ONCE(current->in_eventfd)) return 0; spin_lock_irqsave(&ctx->wqh.lock, flags); - current->in_eventfd_signal = 1; + current->in_eventfd = 1; if (ULLONG_MAX - ctx->count < n) n = ULLONG_MAX - ctx->count; ctx->count += n; if (waitqueue_active(&ctx->wqh)) wake_up_locked_poll(&ctx->wqh, EPOLLIN); - current->in_eventfd_signal = 0; + current->in_eventfd = 0; spin_unlock_irqrestore(&ctx->wqh.lock, flags); return n; @@ -253,8 +253,10 @@ static ssize_t eventfd_read(struct kiocb *iocb, struct iov_iter *to) __set_current_state(TASK_RUNNING); } eventfd_ctx_do_read(ctx, &ucnt); + current->in_eventfd = 1; if (waitqueue_active(&ctx->wqh)) wake_up_locked_poll(&ctx->wqh, EPOLLOUT); + current->in_eventfd = 0; spin_unlock_irq(&ctx->wqh.lock); if (unlikely(copy_to_iter(&ucnt, sizeof(ucnt), to) != sizeof(ucnt))) return -EFAULT; @@ -301,8 +303,10 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c } if (likely(res > 0)) { ctx->count += ucnt; + current->in_eventfd = 1; if (waitqueue_active(&ctx->wqh)) wake_up_locked_poll(&ctx->wqh, EPOLLIN); + current->in_eventfd = 0; } spin_unlock_irq(&ctx->wqh.lock); diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index 305d5f19093b..30eb30d6909b 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h @@ -46,7 +46,7 @@ void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt); static inline bool eventfd_signal_allowed(void) { - return !current->in_eventfd_signal; + return !current->in_eventfd; } #else /* CONFIG_EVENTFD */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 6d877c7e22ff..e02dc270fa2c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -934,7 +934,7 @@ struct task_struct { #endif #ifdef CONFIG_EVENTFD /* Recursion prevention for eventfd_signal() */ - unsigned in_eventfd_signal:1; + unsigned in_eventfd:1; #endif #ifdef CONFIG_IOMMU_SVA unsigned pasid_activated:1;