From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A112D1EB2C for ; Mon, 29 Jul 2024 07:55:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722239735; cv=none; b=aMY4SUud9b2xvSdQw9nmewaMW0Xup1zUn63Oioxgzzv7hjxgOgfu9YHu0VUDT4CHIQ0RGTHSEFmgbTQMFo1I/e+rigYCD9mS0FJp0hxXH2crs4Q/OxrHIsNPLmdIkbqsbcXmLZFXwOMzTyAgmukuv2nlJvWIfWsxeiGk04sRo7s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722239735; c=relaxed/simple; bh=WnCFoXdhmvB/KFCVahslGePJQ1J5DJOUL4hID+qGhBg=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=krgeYLpbL1BDDz4kEuHeffTzIG3tCLOQjtzAqD1RcVrV94B4b+sHgsQCdmNN0DNAwwDe2bXXUx8GvyaF6+rZOi0aRP/rlP+2+VMRCYwnvXZW4jeJz2bkIOFU2z3y5fNdzA6lLOi8SdNkzzbccilSL14IsZ5DSeR9WmIoqdkGYXA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RHlH5tnB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RHlH5tnB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07E86C32786; Mon, 29 Jul 2024 07:55:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1722239735; bh=WnCFoXdhmvB/KFCVahslGePJQ1J5DJOUL4hID+qGhBg=; h=Subject:To:Cc:From:Date:From; b=RHlH5tnBOUGex+XRn1ZvhzqAEwQcSk367cGTMatzcOTbKf4CaXu3oagdrppcRn5jA 7xkagVyD/YXMydfzdqdhAWRM1iAoQzsErP1uSFl+sk8mXOvhoYNb6TKU9uMto8o5Bi SmPx0Mzlz0VSCSnac2/UJw73hDiOjBxE0KuuUABg= Subject: FAILED: patch "[PATCH] io_uring/io-wq: limit retrying worker initialisation" failed to apply to 5.15-stable tree To: asml.silence@gmail.com,axboe@kernel.dk,ju.orth@gmail.com Cc: From: Date: Mon, 29 Jul 2024 09:55:24 +0200 Message-ID: <2024072924-robin-manger-e92b@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 0453aad676ff99787124b9b3af4a5f59fbe808e2 # git commit -s git send-email --to '' --in-reply-to '2024072924-robin-manger-e92b@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: 0453aad676ff ("io_uring/io-wq: limit retrying worker initialisation") 8a565304927f ("io_uring/io-wq: Use set_bit() and test_bit() at worker->flags") eb47943f2238 ("io-wq: Drop struct io_wqe") dfd63baf892c ("io-wq: Move wq accounting to io_wq") da64d6db3bd3 ("io_uring: One wqe per wq") 01e68ce08a30 ("io_uring/io-wq: stop setting PF_NO_SETAFFINITY on io-wq workers") 996d3efeb091 ("io-wq: Fix memory leak in worker creation") 024f15e033a5 ("io_uring: dedup io_run_task_work") a6b21fbb4ce3 ("io_uring: move list helpers to a separate file") ab1c84d855cf ("io_uring: make io_uring_types.h public") 48c13d898084 ("io_uring: explain io_wq_work::cancel_seq placement") e418bbc97bff ("io_uring: move our reference counting into a header") cd40cae29ef8 ("io_uring: split out open/close operations") 453b329be5ea ("io_uring: separate out file table handling code") f4c163dd7d4b ("io_uring: split out fadvise/madvise operations") 0d5847274037 ("io_uring: split out fs related sync/fallocate functions") 531113bbd5bf ("io_uring: split out splice related operations") 11aeb71406dd ("io_uring: split out filesystem related operations") e28683bdfc2f ("io_uring: move nop into its own file") 5e2a18d93fec ("io_uring: move xattr related opcodes to its own file") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 0453aad676ff99787124b9b3af4a5f59fbe808e2 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 10 Jul 2024 18:58:17 +0100 Subject: [PATCH] io_uring/io-wq: limit retrying worker initialisation If io-wq worker creation fails, we retry it by queueing up a task_work. tasK_work is needed because it should be done from the user process context. The problem is that retries are not limited, and if queueing a task_work is the reason for the failure, we might get into an infinite loop. It doesn't seem to happen now but it would with the following patch executing task_work in the freezer's loop. For now, arbitrarily limit the number of attempts to create a worker. Cc: stable@vger.kernel.org Fixes: 3146cba99aa28 ("io-wq: make worker creation resilient against signals") Reported-by: Julian Orth Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/8280436925db88448c7c85c6656edee1a43029ea.1720634146.git.asml.silence@gmail.com Signed-off-by: Jens Axboe diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c index 913c92249522..f1e7c670add8 100644 --- a/io_uring/io-wq.c +++ b/io_uring/io-wq.c @@ -23,6 +23,7 @@ #include "io_uring.h" #define WORKER_IDLE_TIMEOUT (5 * HZ) +#define WORKER_INIT_LIMIT 3 enum { IO_WORKER_F_UP = 0, /* up and active */ @@ -58,6 +59,7 @@ struct io_worker { unsigned long create_state; struct callback_head create_work; + int init_retries; union { struct rcu_head rcu; @@ -745,7 +747,7 @@ static bool io_wq_work_match_all(struct io_wq_work *work, void *data) return true; } -static inline bool io_should_retry_thread(long err) +static inline bool io_should_retry_thread(struct io_worker *worker, long err) { /* * Prevent perpetual task_work retry, if the task (or its group) is @@ -753,6 +755,8 @@ static inline bool io_should_retry_thread(long err) */ if (fatal_signal_pending(current)) return false; + if (worker->init_retries++ >= WORKER_INIT_LIMIT) + return false; switch (err) { case -EAGAIN: @@ -779,7 +783,7 @@ static void create_worker_cont(struct callback_head *cb) io_init_new_worker(wq, worker, tsk); io_worker_release(worker); return; - } else if (!io_should_retry_thread(PTR_ERR(tsk))) { + } else if (!io_should_retry_thread(worker, PTR_ERR(tsk))) { struct io_wq_acct *acct = io_wq_get_acct(worker); atomic_dec(&acct->nr_running); @@ -846,7 +850,7 @@ static bool create_io_worker(struct io_wq *wq, int index) tsk = create_io_thread(io_wq_worker, worker, NUMA_NO_NODE); if (!IS_ERR(tsk)) { io_init_new_worker(wq, worker, tsk); - } else if (!io_should_retry_thread(PTR_ERR(tsk))) { + } else if (!io_should_retry_thread(worker, PTR_ERR(tsk))) { kfree(worker); goto fail; } else {