From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) (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 E17BB22301 for ; Mon, 30 Sep 2024 01:58:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727661493; cv=none; b=eMtu29zO0L7GRu+QdFA04TQnGMQ+PJroDjCESWxxGh/FqYIDOFs88XUyqbe5JFM0ehx6zOUrnnrflKlyMLLCTAA0/Xe6O7U82QTVoSYfdj5BJxXItlmmvD/eMGyX2lDgsHrP+tCfGDCOyyoSu8sVchJBICj28eSupjygBUgfjes= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727661493; c=relaxed/simple; bh=w2KFwUgJePA7vZ/vv00BGqELtnoErd+lDSVXcSEJBn8=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=L4gjBjSfL2kg8pG/CNCiM3ptpBqZPrzL8Qq5+8XH2E3AQQAGU6Hrl6mg45hYsQG05v6vme32o1nogKw0nVnpBo9DvLiz2zi3dCBO7/ekdFhN8KIpsNOfImg2lNuwoaPkC/5KclZIkxzp0iYsWiLs1eWEx/V5BkBb7qpHFRbOuKw= 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=2N2/pkO4; arc=none smtp.client-ip=209.85.214.169 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="2N2/pkO4" Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-20b0b2528d8so41944105ad.2 for ; Sun, 29 Sep 2024 18:58:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1727661489; x=1728266289; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id:from :to:cc:subject:date:message-id:reply-to; bh=LhZMubrKj24mwM8lOh1PoffYDPqPpfavh55XpysKQsg=; b=2N2/pkO4EurnXCk+fpweNmQevLZtrhKHgojrM7lPVMwJDDuUKGToz48He3j7YhEcoZ 2VfkTAyi6R3p9QBEK5V0Hn0aAUnSha48NruD/trM5nQxGrSFPfajlii87XSj9Nx+kk/D asOtb8qoqSEWWcWrVAEhDnO7OELBOEOHG6+gIIXjok4zEcJSPYxJtP6h/F6Y6sOliVW4 HFD+j0zzYA1a7g5olczRIrqI7UUL+skscllYeC8vmdU6bvKtPn1h9vM9sb1HgD/ePDdD Ule96as2B6WLXj3I1rKCMYQluuOJM1MEqBjcifF8pHoAEzpapYUz85Nfyn1fQuHPpzqc 2amQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727661489; x=1728266289; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=LhZMubrKj24mwM8lOh1PoffYDPqPpfavh55XpysKQsg=; b=J71mfFzCJR+7+xuAA4WShXZ+Y+pDopcsLnqqxZDmBKNp2/OdLQ6c/QaMJDalOdO2oB RMqg50vvpNnqVIvfmH38t09llWHgsXLRhram7vcMg5rckNHvv3jdRd5NkJtZM0M2a7Vw 5p4heFXOd85COJLyDjl5DGGZKntjRGlZENJ66Bp+eTz5DTRHxS9dufWhitn5H/Da6GWt plY4cZhKIjrLZQx5EAHaTJQTbpJeYLMnpjOZ8uhZA8PK1XBn7ILr6If68itShxrJndI7 fD0RtGomQsKll01FSJPnoh5wwin4HKAFyCq7mq4fuQVpeHL6C0Yny2xUL+SpQBFj4zUE 5okQ== X-Forwarded-Encrypted: i=1; AJvYcCUzyb7pdhE4DnfIUnb48q4dkStSAoJQKKkMiFYWyzj2a5/ocbd9TGUge+sKFv7iFn5vdLqXp6VUNw==@vger.kernel.org X-Gm-Message-State: AOJu0YwWVKXlddHvB3l1yG8uHNk5IEcVVbXnQlPEiC+nNbA7I1wJJfjv 5upBqAP7IJDyXL24885AzWG8y85eACpzjHrtW97STRE7ByRNoSppGn0tpN9COro= X-Google-Smtp-Source: AGHT+IFqtNWV0JcbXD9xeAq0dKdNc949KYclzYOaIevcMR0yQ9FN7pfVl0dXCpVprfLIPcKFlvivtw== X-Received: by 2002:a17:902:d50c:b0:20b:8341:d547 with SMTP id d9443c01a7336-20b8341d7fbmr37394925ad.26.1727661488745; Sun, 29 Sep 2024 18:58:08 -0700 (PDT) Received: from [192.168.1.150] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-20b37e0dd6bsm44803055ad.120.2024.09.29.18.58.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 29 Sep 2024 18:58:07 -0700 (PDT) Message-ID: <8457d4bf-e7ee-4cc8-a69c-c82212c85f5b@kernel.dk> Date: Sun, 29 Sep 2024 19:58:06 -0600 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] io_uring/net: fix a multishot termination case for recv To: Pavel Begunkov , io-uring References: <2ddaef0b-0def-4886-ade6-8fedd7a0965f@kernel.dk> <0542e045-e5ee-41d3-b44f-5b6f9657f90a@gmail.com> Content-Language: en-US From: Jens Axboe In-Reply-To: <0542e045-e5ee-41d3-b44f-5b6f9657f90a@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/29/24 1:25 PM, Pavel Begunkov wrote: > On 9/28/24 13:40, Jens Axboe wrote: >> On 9/28/24 6:18 AM, Jens Axboe wrote: >>> diff --git a/io_uring/net.c b/io_uring/net.c >>> index f10f5a22d66a..18507658a921 100644 >>> --- a/io_uring/net.c >>> +++ b/io_uring/net.c >>> @@ -1133,6 +1133,7 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) >>> int ret, min_ret = 0; >>> bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; >>> size_t len = sr->len; >>> + bool mshot_finished; >>> if (!(req->flags & REQ_F_POLLED) && >>> (sr->flags & IORING_RECVSEND_POLL_FIRST)) >>> @@ -1187,6 +1188,7 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) >>> req_set_fail(req); >>> } >>> + mshot_finished = ret <= 0; >>> if (ret > 0) >>> ret += sr->done_io; >>> else if (sr->done_io) >>> @@ -1194,7 +1196,7 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) >>> else >>> io_kbuf_recycle(req, issue_flags); >>> - if (!io_recv_finish(req, &ret, kmsg, ret <= 0, issue_flags)) >>> + if (!io_recv_finish(req, &ret, kmsg, mshot_finished, issue_flags)) >>> goto retry_multishot; >>> return ret; >> >> On second thought, I don't think we can get into this situation - >> sr->done_io is only ever used for recv if we had to retry after getting >> some data. And that only happens if MSG_WAITALL is set, which is not >> legal for multishot and will result in -EINVAL. So don't quite see how >> we can run into this issue. But I could be missing something... >> >> Comments? > > I noticed the chunk months ago, it's definitely a sloppy one, but I > deemed it not to be an actual problem after trying to exploit it at > the moment. Yes, might not be a bad idea to still do the tweak. Not because we can _currently_ hit it, but because it could be possible in the future and just get overlooked. Thanks for confirming :-) -- Jens Axboe