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 E5BA41F61C for ; Wed, 19 Mar 2025 02:09:59 +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=1742350200; cv=none; b=jZoPJl+CaaI8yNUuVTGny5Rqpk3fGsYlerel4OGijPr2gGA6yaYI7Epwg1aOzbaU0KQ6zglHJ8LXREGSDge/QPMz/jsAawJNYTdj3zMgjYHK3wnApA04sCFQlr9XyL2OX7XYyAt51ft/rDVW2cWMtIf1Hr4iMDun9dq2Bv+Co/Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742350200; c=relaxed/simple; bh=BMKXVsjs9d5C7HIMhy6mbIS5Bj0G9CYS/LAqg8DGC1A=; h=Content-Type:MIME-Version:Subject:From:Message-Id:Date:References: In-Reply-To:To:Cc; b=sb35xFF/KjwlsSnzPwjfTC+q3JUvD0s9/yzloV8dtrMFLCmDGiVPrEitn3TosrsGC6rRKSebGZ+rgGO2q8FAnwF9XaKpxw6Tr4iaV4uiQupMvFnSJB3tk+EnnhhdOnFwGfy1SRfQb3vhQXLPXqeuLsiR5sNnCGCXaGEi5c88e4w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JQ95hWc3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JQ95hWc3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 69577C4CEDD; Wed, 19 Mar 2025 02:09:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742350199; bh=BMKXVsjs9d5C7HIMhy6mbIS5Bj0G9CYS/LAqg8DGC1A=; h=Subject:From:Date:References:In-Reply-To:To:Cc:From; b=JQ95hWc37Sf9XRTT4K/IjWsT+pBttgjWdXjXt3Q8G0OhjF32mepnV56viLB2RBrJf ZXqIUvtM9BRf+WRrGdxDEDTHDRErY3X4FTObv5Dhq9IV55kSw5RfHrUMUns0rg2KPN pryj+9XT2gWnMUGvtFFnnfXaT4Mfzj3W+v+GMOe+/hqs9pB4W9W9uMmXctUFT5rAf+ VE/8TA+3l5EMp0oVsRcEl5KTK2KCnprkiPJSq3dfB4FGqPc2AnL70pqNezlQayX2YU 1hHS03z5pvqtKlyCMXlncKdu5k88MK4rPFyAciT3Nv2/+hxs/tWHxOP2hiyTGZzY/T O9FD/y6fDUiYQ== Received: from [10.30.226.235] (localhost [IPv6:::1]) by aws-us-west-2-korg-oddjob-rhel9-1.codeaurora.org (Postfix) with ESMTP id 34A75380DBEE; Wed, 19 Mar 2025 02:10:36 +0000 (UTC) Content-Type: text/plain; charset="utf-8" Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH bpf-next] bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage From: patchwork-bot+netdevbpf@kernel.org Message-Id: <174235023475.536550.5782919972344813926.git-patchwork-notify@kernel.org> Date: Wed, 19 Mar 2025 02:10:34 +0000 References: <20250318182759.3676094-1-martin.lau@linux.dev> In-Reply-To: <20250318182759.3676094-1-martin.lau@linux.dev> To: Martin KaFai Lau Cc: bpf@vger.kernel.org, ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, kernel-team@meta.com Hello: This patch was applied to bpf/bpf-next.git (master) by Alexei Starovoitov : On Tue, 18 Mar 2025 11:27:59 -0700 you wrote: > From: Martin KaFai Lau > > The current cgrp storage has a percpu counter, bpf_cgrp_storage_busy, > to detect potential deadlock at a spin_lock that the local storage > acquires during new storage creation. > > There are false positives. It turns out to be too noisy in > production. For example, a bpf prog may be doing a > bpf_cgrp_storage_get on map_a. An IRQ comes in and triggers > another bpf_cgrp_storage_get on a different map_b. It will then > trigger the false positive deadlock check in the percpu counter. > On top of that, both are doing lookup only and no need to create > new storage, so practically it does not need to acquire > the spin_lock. > > [...] Here is the summary with links: - [bpf-next] bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage https://git.kernel.org/bpf/bpf-next/c/f4edc66e48a6 You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html