From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f53.google.com (mail-pj1-f53.google.com [209.85.216.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C6981EB41 for ; Mon, 18 Mar 2024 02:46:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710729985; cv=none; b=cbJNtLJBEyrH20/pSCTZ5NzMfWu85AuwSIU3DI8cP3FfVdkJSX5JYlcqHXlnUSOpNsIciWY8Ftk5JcWkyXonFJPKS/xj1pE3J28M/cRmddP4vc3lHZKj6cp2ukZe5RPp/Osyeymq18eg6r58sk3j01LjUVNbT0HVa5oohN4kgIw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710729985; c=relaxed/simple; bh=/Fc+4oRkovkzFAOhEmV/xQeoPBkNvhIu3HLuHMHDw7s=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=k79OSTVB8Sdm/WWbTJISrt3HNab/97qfhiNLsIwQFHd09t/gcBtoHRTVW85tpP0rXnrp3kqDqxrjjXjfEQ3Y7EDFI5tveQ+czXO6AtZsE8mXXbgPIbobzNj+16SFF+FotBUybCvArMjs2/e0AvjV34QGdwVvIWX69RUaWq9+z4c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=ZwtmkcyS; arc=none smtp.client-ip=209.85.216.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="ZwtmkcyS" Received: by mail-pj1-f53.google.com with SMTP id 98e67ed59e1d1-29f8ae4eae5so196204a91.0 for ; Sun, 17 Mar 2024 19:46:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1710729983; x=1711334783; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=KjWfVw0geUGg9os2zUxZI97lEAPbX7MKsu9VHaF/9Gc=; b=ZwtmkcySgF+bypDPDGt8aqG1XAOKA7RVAfl2jD0WdsxR0YxFIxEhmPPLPcr1lgSWwr m3OQLDs4lES1F1k2FF5Yjn+wdUXqx4PzFlPN9gB+f+vDIX4TTx4V6tgp9qbdeUwyE9bO pnIyIrokoyFr0Q9zat+cBJNsdhkozBkWMnT49r7jkAOUSaCjFg0M5Cqt3RhwY8wDmPV7 sG8EMuIf173AMNbsS87QYtzGGiew6nvpeDLnQ5ipp/IoqdHD0m0GkHtp8IQoPFmv2tYM 3Oed6zDSQ+eA1UPSdRvBA6kesRZ3NK0ns+sT8Gvd3D8/DjB8iksEtf2OUl3LtrzJzfSo wMWA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710729983; x=1711334783; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=KjWfVw0geUGg9os2zUxZI97lEAPbX7MKsu9VHaF/9Gc=; b=GJPl55PFvbN1O8dsO9a2ax/OTPRohxyAo+uLY6uWM2Dj0vfM3gM6Ic+fTWFeKJXnNe x/bbRuX7+KeHC65WLwUKhuuiFxl8KIdICjJVSpmB8KjQYUt7Qh210ZuluWMbTGmL5Hqa 5Ey+U9BH5/ZMLmHHQ9xMnQCXOM7Ah1OrfAr7fP2VTlj0YZGYOGWrkfyIK9Jj+rk2QrzJ YfEhRSwMrLMW23HHxqA5Jt4dSvM4wZ3BuncIYGqPpD1DpOkSviaDW4jXDpJY+AJdB7G8 gSCrTQK99mAnRrvv1fai3ftyYquVojo4MfvfwUvLh8It529P0qqNS5uQI4TrW4NQSY24 eDQQ== X-Forwarded-Encrypted: i=1; AJvYcCUC4Bo2bMV51Pm+k0ovR46Bq16he9P6+n7ASNrtM4m1khTmReJr2CQSAmyJEHQtx+zXGj0zLyYPnq0FU/JJhO7bEPpXco9n5if1M7k= X-Gm-Message-State: AOJu0YwPULGtDNGXU8t3SR0fe9mJK//JjYWkgwd9FOKHQDC1YVojZpXn gnVXtlez/hDWmUbCwPk0iHpDocM8Nc/Zx7ehydqDjBRYW2vrtRrbedXGJmVCJpw= X-Google-Smtp-Source: AGHT+IH2JhxGa6l1KueVze5LCL1jEexDSTp81Aeij3wHWUgS2Na6kIRx8SWSA5T147mgUW+NuRE9cg== X-Received: by 2002:a17:902:ea03:b0:1dd:a3d6:3aff with SMTP id s3-20020a170902ea0300b001dda3d63affmr12244830plg.3.1710729982860; Sun, 17 Mar 2024 19:46:22 -0700 (PDT) Received: from [192.168.1.150] ([198.8.77.194]) by smtp.gmail.com with ESMTPSA id jj18-20020a170903049200b001dffa017c5esm3594937plb.22.2024.03.17.19.46.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 17 Mar 2024 19:46:22 -0700 (PDT) Message-ID: <704be04f-ef96-4e24-a968-753bf483bc30@kernel.dk> Date: Sun, 17 Mar 2024 20:46:21 -0600 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 02/14] io_uring/cmd: fix tw <-> issue_flags conversion Content-Language: en-US To: Pavel Begunkov , Ming Lei Cc: io-uring@vger.kernel.org, linux-block@vger.kernel.org, Kanchan Joshi References: <6291a6f9-61e0-4e3f-b070-b61e8764fb63@kernel.dk> <33800cbe-f87b-42e6-93ca-d1d1840deecf@gmail.com> From: Jens Axboe In-Reply-To: <33800cbe-f87b-42e6-93ca-d1d1840deecf@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/17/24 8:43 PM, Pavel Begunkov wrote: >>>>>> diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c >>>>>> index f197e8c22965..ec38a8d4836d 100644 >>>>>> --- a/io_uring/uring_cmd.c >>>>>> +++ b/io_uring/uring_cmd.c >>>>>> @@ -56,7 +56,11 @@ EXPORT_SYMBOL_GPL(io_uring_cmd_mark_cancelable); >>>>>> static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts) >>>>>> { >>>>>> struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); >>>>>> - unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED; >>>>>> + unsigned issue_flags = IO_URING_F_UNLOCKED; >>>>>> + >>>>>> + /* locked task_work executor checks the deffered list completion */ >>>>>> + if (ts->locked) >>>>>> + issue_flags = IO_URING_F_COMPLETE_DEFER; >>>>>> ioucmd->task_work_cb(ioucmd, issue_flags); >>>>>> } >>>>>> @@ -100,7 +104,9 @@ void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2, >>>>>> if (req->ctx->flags & IORING_SETUP_IOPOLL) { >>>>>> /* order with io_iopoll_req_issued() checking ->iopoll_complete */ >>>>>> smp_store_release(&req->iopoll_completed, 1); >>>>>> - } else if (!(issue_flags & IO_URING_F_UNLOCKED)) { >>>>>> + } else if (issue_flags & IO_URING_F_COMPLETE_DEFER) { >>>>>> + if (WARN_ON_ONCE(issue_flags & IO_URING_F_UNLOCKED)) >>>>>> + return; >>>>>> io_req_complete_defer(req); >>>>>> } else { >>>>>> req->io_task_work.func = io_req_task_complete; >>>>> >>>>> 'git-bisect' shows the reported warning starts from this patch. >>> >>> Thanks Ming >>> >>>> >>>> That does make sense, as probably: >>>> >>>> + /* locked task_work executor checks the deffered list completion */ >>>> + if (ts->locked) >>>> + issue_flags = IO_URING_F_COMPLETE_DEFER; >>>> >>>> this assumption isn't true, and that would mess with the task management >>>> (which is in your oops). >>> >>> I'm missing it, how it's not true? >>> >>> >>> static void ctx_flush_and_put(struct io_ring_ctx *ctx, struct io_tw_state *ts) >>> { >>> ... >>> if (ts->locked) { >>> io_submit_flush_completions(ctx); >>> ... >>> } >>> } >>> >>> static __cold void io_fallback_req_func(struct work_struct *work) >>> { >>> ... >>> mutex_lock(&ctx->uring_lock); >>> llist_for_each_entry_safe(req, tmp, node, io_task_work.node) >>> req->io_task_work.func(req, &ts); >>> io_submit_flush_completions(ctx); >>> mutex_unlock(&ctx->uring_lock); >>> ... >>> } >> >> I took a look too, and don't immediately see it. Those are also the two >> only cases I found, and before the patches, looks fine too. >> >> So no immediate answer there... But I can confirm that before this >> patch, test passes fine. With the patch, it goes boom pretty quick. > > Which test is that? ublk generic/004? Yep, it won't make it through one run of: sudo make test T=generic/004 with it. >> Either directly off putting the task, or an unrelated memory crash >> instead. > > If tw locks it should be checking for deferred completions, > that's the rule. Maybe there is some rouge conversion and locked > came not from task work executor... I'll need to stare more > closely Yeah not sure what it is, but I hope you can reproduce with the above. -- Jens Axboe