From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f45.google.com (mail-io1-f45.google.com [209.85.166.45]) (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 C12B213C67E for ; Fri, 24 Jan 2025 20:47:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737751637; cv=none; b=m0RAmaa+shqU5BSxEzUaJwfJ9/EPBaisMfuNUtxgeyEdpXca1k316ogkC8wCw913cOE4VTWp0fODL1uFMnfZl93Nd0KZh508kqQSfQxTzHdMWFcHOFY38H51LKmWGKcYsKc5p8rjsiNdXlN9nnfUuHF1Cr5hmnb8nNnllePIUL4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737751637; c=relaxed/simple; bh=tpL/TsUXCd7sfV5n5avBkyJe0b5ilPtT/vNnXnDgFp8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QDx8A5P+Wk487DYr5xK/uMkx8qdYB/VdAvEIFwesr7xvAFaxRfIeiRyzl68p59z/6fzKlojfA2ddwQcKj87rDp5Qmj8vSA/iY/266XR3X+GZs4q+TRoY6gu6l7biGhxUtxMlchIA399YJy8V/cfRJcUNiIobZAosFoC46YAVQz8= 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=JphXKevz; arc=none smtp.client-ip=209.85.166.45 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="JphXKevz" Received: by mail-io1-f45.google.com with SMTP id ca18e2360f4ac-844e39439abso68662239f.1 for ; Fri, 24 Jan 2025 12:47:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1737751634; x=1738356434; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=DaJqWcsK9tZSSa1bedlEwird8dsdxNAvQOMECXsQVDM=; b=JphXKevzDnvBkm6EeIp8rLMZxC+mTYbXsbjpDPz5An0hzpGiXLWxcfF9cISQ1a05PT nTouR7unYQm7Ew3uu7mml3gytB0fTlqfKfIgEEe0U5MzE1YB+oLhdrZZBWkTctM1OsjH Ly+nH9cXJFLdLFu6xsZlCklvsjAhgfIKf48ZDCW81C0Gvyhv7m4dAW9MLFdU5+CsHzqq MM4ZNA96t9bqMN2/Blt5ndj3fmuJz3hv3bBitkiG+x/xHq2ewBw804f0Kq3ubo9PygBl TEDklNvi7i+Mnk2En1Nfi+Yd0fMl7auFMWjFl9VThfYmEqZ+tDPlDr1nV88ca5BMLtTL 2rGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1737751634; x=1738356434; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=DaJqWcsK9tZSSa1bedlEwird8dsdxNAvQOMECXsQVDM=; b=arz1lD/4WO1oDoR9m8KBkvMdJLuAcr5UzvxlefJXzbXcNcI1xY1r5TKc1T2ZDR+Rhc MgIlbE5XcorW7eVwauYIYGk7vJ/PeGKOpqGMxbMFWQhSWoHtr5K4zydst66mJ5dqEw5H +FNmd9nPTjc61s35w2TWweaTGlEN/H+GudO46ujfPWGhszVNDudWyj09qLeNJLEOkErt RsKBoRmbirwOBoNCkYaMxDYDmjc7V3ZsTCm7/19ULO7YyumwgYBS4XAbpMZ1z0BspMHQ Ex5sDdQN+soGiV24WrKiOi227kFQJsn6A42nahBmqZ+3HeQNj/1z7eb0x17E0YLQU4BZ N47Q== X-Forwarded-Encrypted: i=1; AJvYcCX0u8DJ7kLevOa3lVYgs1iHO4nvgLlWaASlW+5LHnTrXJdN0pz+gC1W5UYlJ1DfACnLVe2OUQO9fg==@vger.kernel.org X-Gm-Message-State: AOJu0Yy9Wq17GzWmMFa+zsaTDH2k23tnKubiBshSsmZKcQXH82a3r9l4 bqXwx0NQHMQmF/xNlzsxlp00ethsdul8D4pef6ws1vTCZlZukDcD2/6A9nTbBZE= X-Gm-Gg: ASbGnctJ1eWn34VmNYKDzvWxaflW8Izb9bn0bqcWGi6zFY7mMLKFPj0XpbVHbhpOHgM eh5dNArwHFSv/ZyPe/wEM7eLbrLZlBAy3Q36i23LhesJf5Mkc0nAchEYPuTEQDMiYlKOk2xg9Yu BIPeeI7mf0OyfjfkNUW31NmFXGacXA4o6wovBY1qTqRYRLwxIF2xefW1AYf9lsmOzwaLZjTGHPG g29PC2bf9H8ezr9NKwN3Sr3GSuWq2OPCJWlIgPwwZiqmGhRJ90U9XISCIkVPePmMWmTSQuis42i xA== X-Google-Smtp-Source: AGHT+IGa85kSO/T2HDmDdm/vU4Hoj1ggyeLKawatGyavTHXo/cgFo8f8QAYHdaFPxfLDH5S6Q+Hu0Q== X-Received: by 2002:a05:6602:6b12:b0:84a:5133:9cd8 with SMTP id ca18e2360f4ac-851b62835afmr2228437839f.10.1737751633707; Fri, 24 Jan 2025 12:47:13 -0800 (PST) Received: from [192.168.1.150] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id ca18e2360f4ac-8521df2ce32sm89978739f.18.2025.01.24.12.47.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Jan 2025 12:47:12 -0800 (PST) Message-ID: <721da692-bd23-4a73-94df-1170e3d379be@kernel.dk> Date: Fri, 24 Jan 2025 13:47:12 -0700 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 stable-6.1 1/1] io_uring: fix waiters missing wake ups To: Pavel Begunkov , io-uring@vger.kernel.org, stable@vger.kernel.org Cc: Xan Charbonnet , Salvatore Bonaccorso References: <760086647776a5aebfa77cfff728837d476a4fd8.1737718881.git.asml.silence@gmail.com> Content-Language: en-US From: Jens Axboe In-Reply-To: <760086647776a5aebfa77cfff728837d476a4fd8.1737718881.git.asml.silence@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/24/25 11:53 AM, Pavel Begunkov wrote: > [ upstream commit 3181e22fb79910c7071e84a43af93ac89e8a7106 ] > > There are reports of mariadb hangs, which is caused by a missing > barrier in the waking code resulting in waiters losing events. > > The problem was introduced in a backport > 3ab9326f93ec4 ("io_uring: wake up optimisations"), > and the change restores the barrier present in the original commit > 3ab9326f93ec4 ("io_uring: wake up optimisations") > > Reported by: Xan Charbonnet > Fixes: 3ab9326f93ec4 ("io_uring: wake up optimisations") > Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1093243#99 > Signed-off-by: Pavel Begunkov > --- > io_uring/io_uring.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c > index 9b58ba4616d40..e5a8ee944ef59 100644 > --- a/io_uring/io_uring.c > +++ b/io_uring/io_uring.c > @@ -592,8 +592,10 @@ static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) > io_commit_cqring(ctx); > spin_unlock(&ctx->completion_lock); > io_commit_cqring_flush(ctx); > - if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) > + if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) { > + smp_mb(); > __io_cqring_wake(ctx); > + } > } We could probably just s/__io_cqring_wake/io_cqring_wake here to get the same effect. Not that it really matters, it's just simpler. -- Jens Axboe