From mboxrd@z Thu Jan 1 00:00:00 1970 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 4C0CBC433F5 for ; Thu, 31 Mar 2022 19:14:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231398AbiCaTQm (ORCPT ); Thu, 31 Mar 2022 15:16:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238640AbiCaTQl (ORCPT ); Thu, 31 Mar 2022 15:16:41 -0400 Received: from mail-il1-x12f.google.com (mail-il1-x12f.google.com [IPv6:2607:f8b0:4864:20::12f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E19E60DA7 for ; Thu, 31 Mar 2022 12:14:53 -0700 (PDT) Received: by mail-il1-x12f.google.com with SMTP id 8so481676ilq.4 for ; Thu, 31 Mar 2022 12:14:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:content-language:to:from :subject:content-transfer-encoding; bh=nQmTj0sday0Ov5/qAiE2GvMp3p9VdvBqpoHfsBdYNig=; b=pjfLad/2zTzMSwwPTqCPDzG0jkjCh4SLAYYMlrjjB9Fehd4NPgYvhkKuRqy2YMJ3pH wYeodigpW1GXtTHGXGHJOXZSHpUrlyCYhFvt5XK7aqo0pR37doGpe9oWuiRDhI8lz7DW DtQpT5kcDUkTr17oiLky2r+HonSBnrOG0kcc2HLEOuyVzd6XeRxfZn/1dMzCwPfTRrGP RAPXD1YNqt7p16wr96x1Yjc4wDs3qYfqcVqYnOtLI4DQ2lE6/mPN9En2OkfDGajmpf81 emaXK9eR2MfOlyYI1wp22JnQU4k9Ze7mPp7AorMUud0YDLpHpemI86penEGmcrEffiQc nRLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent :content-language:to:from:subject:content-transfer-encoding; bh=nQmTj0sday0Ov5/qAiE2GvMp3p9VdvBqpoHfsBdYNig=; b=z+9MtXpfV2iMubovBRNbRzw6OMC5OWXfHglufGzLjH7Lr5Ba9gKzlrGsOFoTy5Mfg6 h4SGQ9kHnTd61OjR77T1qXMKk8jwgwiRTUPer2BWOhSz0nNd7dMLp5fzOnXmpefhwhNI CF/UCgE5cKbbTWDWrwlHHz/CQsVAZdczWGBTn7VyMQyjg2XEagW36thJPBJ3lFn2fdK9 WWLUgLM7YJ15CIiWN/Amp0+A+BW77PNuP2h8N9rdIXcXWNY54+PJsQbVuvfmTI4nTzyP AbjljhjEJ1+8gyAyyq/ScJBBoeF+GR6j3TAUvLyEyij9kY2aBf3dBdktR1gUNcXsr7C0 MJww== X-Gm-Message-State: AOAM530QVdL3sEkQ3w19kVeaLMYdDqsbEorSo85whBzbEWzbeeMYDVV9 K519FU3KFRfRhpChNfbT6Q8PQuWYvx9UbgOz X-Google-Smtp-Source: ABdhPJyvkivqD0FkZoFgBp4ku2zw+zlYzLL+/LX+bFs8A7ns7vKxcSDf91m/BbQbDvl1LgOPqmMuJg== X-Received: by 2002:a05:6e02:1caa:b0:2c8:811f:56ba with SMTP id x10-20020a056e021caa00b002c8811f56bamr14083319ill.90.1648754092048; Thu, 31 Mar 2022 12:14:52 -0700 (PDT) Received: from [192.168.1.172] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id p18-20020a92c112000000b002c9cf295661sm134211ile.78.2022.03.31.12.14.51 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 31 Mar 2022 12:14:51 -0700 (PDT) Message-ID: <06f02d41-361b-c66a-46b6-c9a90d4edcc2@kernel.dk> Date: Thu, 31 Mar 2022 13:14:51 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Content-Language: en-US To: io-uring From: Jens Axboe Subject: [PATCH v2] io_uring: drop the old style inflight file tracking Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org io_uring tracks requests that are referencing an io_uring descriptor to be able to cancel without worrying about loops in the references. Since we now assign the file at execution time, the easier approach is to drop a potentially problematic reference before we punt the request. This eliminates the need to special case these types of files beyond just marking them as such, and simplifies cancelation quite a bit. This also fixes a recent issue where an async punted tee operation would with the io_uring descriptor as the output file would crash when attempting to get a reference to the file from the io-wq worker. We could have worked around that, but this is the much cleaner fix. Fixes: 734a69489dd7 ("io_uring: defer file assignment") Reported-by: syzbot+c4b9303500a21750b250@syzkaller.appspotmail.com Signed-off-by: Jens Axboe --- v2: right after sending out v1 I realized that we can then also kill the weird cancelation hacks we have for retaining a tracked file across punt. Kill it with fire, this drops even more dead code. diff --git a/fs/io_uring.c b/fs/io_uring.c index 00bc123ab5e7..a607d023c85c 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -113,8 +113,7 @@ IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS) #define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \ - REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \ - REQ_F_ASYNC_DATA) + REQ_F_POLLED | REQ_F_CREDS | REQ_F_ASYNC_DATA) #define IO_TCTX_REFS_CACHE_NR (1U << 10) @@ -501,7 +500,6 @@ struct io_uring_task { const struct io_ring_ctx *last; struct io_wq *io_wq; struct percpu_counter inflight; - atomic_t inflight_tracked; atomic_t in_idle; spinlock_t task_lock; @@ -1190,6 +1188,7 @@ static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type, static void io_clean_op(struct io_kiocb *req); static struct file *io_file_get(struct io_ring_ctx *ctx, struct io_kiocb *req, int fd, bool fixed); +static void io_drop_inflight_file(struct io_kiocb *req); static void __io_queue_sqe(struct io_kiocb *req); static void io_rsrc_put_work(struct work_struct *work); @@ -1430,29 +1429,9 @@ static bool io_match_task(struct io_kiocb *head, struct task_struct *task, bool cancel_all) __must_hold(&req->ctx->timeout_lock) { - struct io_kiocb *req; - if (task && head->task != task) return false; - if (cancel_all) - return true; - - io_for_each_link(req, head) { - if (req->flags & REQ_F_INFLIGHT) - return true; - } - return false; -} - -static bool io_match_linked(struct io_kiocb *head) -{ - struct io_kiocb *req; - - io_for_each_link(req, head) { - if (req->flags & REQ_F_INFLIGHT) - return true; - } - return false; + return cancel_all; } /* @@ -1462,24 +1441,9 @@ static bool io_match_linked(struct io_kiocb *head) static bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task, bool cancel_all) { - bool matched; - if (task && head->task != task) return false; - if (cancel_all) - return true; - - if (head->flags & REQ_F_LINK_TIMEOUT) { - struct io_ring_ctx *ctx = head->ctx; - - /* protect against races with linked timeouts */ - spin_lock_irq(&ctx->timeout_lock); - matched = io_match_linked(head); - spin_unlock_irq(&ctx->timeout_lock); - } else { - matched = io_match_linked(head); - } - return matched; + return cancel_all; } static inline bool req_has_async_data(struct io_kiocb *req) @@ -1642,14 +1606,6 @@ static inline bool io_req_ffs_set(struct io_kiocb *req) return req->flags & REQ_F_FIXED_FILE; } -static inline void io_req_track_inflight(struct io_kiocb *req) -{ - if (!(req->flags & REQ_F_INFLIGHT)) { - req->flags |= REQ_F_INFLIGHT; - atomic_inc(¤t->io_uring->inflight_tracked); - } -} - static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req) { if (WARN_ON_ONCE(!req->link)) @@ -2560,6 +2516,8 @@ static void io_req_task_work_add(struct io_kiocb *req, bool priority) WARN_ON_ONCE(!tctx); + io_drop_inflight_file(req); + spin_lock_irqsave(&tctx->task_lock, flags); if (priority) wq_list_add_tail(&req->io_task_work.node, &tctx->prior_task_list); @@ -7198,11 +7156,6 @@ static void io_clean_op(struct io_kiocb *req) kfree(req->apoll); req->apoll = NULL; } - if (req->flags & REQ_F_INFLIGHT) { - struct io_uring_task *tctx = req->task->io_uring; - - atomic_dec(&tctx->inflight_tracked); - } if (req->flags & REQ_F_CREDS) put_cred(req->creds); if (req->flags & REQ_F_ASYNC_DATA) { @@ -7487,6 +7440,19 @@ static inline struct file *io_file_get_fixed(struct io_ring_ctx *ctx, return file; } +/* + * Drop the file for requeue operations. Only used of req->file is the + * io_uring descriptor itself. + */ +static void io_drop_inflight_file(struct io_kiocb *req) +{ + if (unlikely(req->flags & REQ_F_INFLIGHT)) { + fput(req->file); + req->file = NULL; + req->flags &= ~REQ_F_INFLIGHT; + } +} + static struct file *io_file_get_normal(struct io_ring_ctx *ctx, struct io_kiocb *req, int fd) { @@ -7495,8 +7461,8 @@ static struct file *io_file_get_normal(struct io_ring_ctx *ctx, trace_io_uring_file_get(ctx, req, req->user_data, fd); /* we don't allow fixed io_uring files */ - if (file && unlikely(file->f_op == &io_uring_fops)) - io_req_track_inflight(req); + if (unlikely(file && unlikely(file->f_op == &io_uring_fops))) + req->flags |= REQ_F_INFLIGHT; return file; } @@ -9412,7 +9378,6 @@ static __cold int io_uring_alloc_task_context(struct task_struct *task, xa_init(&tctx->xa); init_waitqueue_head(&tctx->wait); atomic_set(&tctx->in_idle, 0); - atomic_set(&tctx->inflight_tracked, 0); task->io_uring = tctx; spin_lock_init(&tctx->task_lock); INIT_WQ_LIST(&tctx->task_list); @@ -10605,7 +10570,7 @@ static __cold void io_uring_clean_tctx(struct io_uring_task *tctx) static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked) { if (tracked) - return atomic_read(&tctx->inflight_tracked); + return 0; return percpu_counter_sum(&tctx->inflight); } -- Jens Axboe