From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f177.google.com (mail-oi1-f177.google.com [209.85.167.177]) (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 7B5CEC2D0 for ; Thu, 14 Mar 2024 03:04:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710385481; cv=none; b=aE0wo63stp7EUgs2nzi+VOgGVfbKe8AFQCXJNeb5l4CwpA5Zx5jiFMczxxuAU7aEnUv/JKsP1hrIc3hafRV7eMtL3kA4xbajxgezLJL9JNXn+DDcpJ/H8vdil4CpuOblXFSV6pd1l4b36mujZFyryDIQ/vhrafL9f/cPREE5Qh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710385481; c=relaxed/simple; bh=bJjBwjuhEPyH1J1zFhdFWl6hJIg2k+e5LEAbP8QrZVw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bHgnyBZmRTPSZBOAQfoBhfFY+9hXfWuJkTGhAFe+ICW1OhipOlALUwFiODg4FJEFoBuqwzcX74g2leOb4o5KcvY6hSRTup6qVLt+3vpIlIddtsenRQoFWl3tWSzkaBEmjSzlSEKv+C1Fjustrt165a943EvJhjVua9gnkGrThZ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=VFHE9Ulf; arc=none smtp.client-ip=209.85.167.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="VFHE9Ulf" Received: by mail-oi1-f177.google.com with SMTP id 5614622812f47-3c1e992f069so269899b6e.3 for ; Wed, 13 Mar 2024 20:04:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1710385478; x=1710990278; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=7M92JDTBKJBnzq2c5WZ2iPAaVSzm7Qg8SLrpTCfSZTE=; b=VFHE9UlfrI4SWRGUmDdXLzy0IUnnrDDfGnSo/2JniGXAXU1NR3G1k0IpW7O7zu5Etu 1nvVq7RyjH52cH7wo3wQYinrQNrJHOWhm0rs0lPayPuZgqB24m8pafzDFwha1T9etv8c Gbiy0eZluBo22TJ14OVQkirt0N4k2/oM8B8rc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710385478; x=1710990278; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=7M92JDTBKJBnzq2c5WZ2iPAaVSzm7Qg8SLrpTCfSZTE=; b=KjgXa6awmHYDl4srMXUMdIsrx0zliOXorQDML1Yjc98BJKHAwSTgIQjzO6YwYAP5t7 6mhIvs/nmeMd+bTV/Q8+xWVQ1gmmhADN/NAfHuGTq9Ml3c/EKZJAU4xDkC/Zr+6J8gF0 gPR8UoA8aLNzml9A52R5MR4NeRSEvY6Q9QQmtKeFtODuGN5SfWqFOeFuYxdiU/IkO3xm YmAFj1oyj8Ks+cppMdS30SXaJzh1L4I/gWUVceI1Ine2fOgca8J6RYx8n216PZKdJM/3 FZK0j6CA2I+HrUbI5HBPddjwIub7H7FEJ71EV0QEInvOlkgk0SBmLT7N4BozFkshROU7 H6LQ== X-Forwarded-Encrypted: i=1; AJvYcCW6JwHPnYokdn+cV9O6x3lYW/5IqsPh4Px8Hck7wGuI0nhcAdOOnO2SNLBoQ83ipc4WlZnk4TUczSXpd77ZiobNOk75QQqr X-Gm-Message-State: AOJu0YxeFOuZ94qRfy9jzK+flY3fOrPhRHcqGvFUqdFddD5J41RKqmoG rXqh0c3c4ebZB44HjRynF5J83IVd1z1sIrfj/2CwCaD0Cw73OeV22LuzfeYdjg== X-Google-Smtp-Source: AGHT+IGX78gwvPQsRfMbGbqRKOXXJL6wFsOcabHKtVC9b8pu0uClVKBZQQGqmmU0LqjpbUu+LXJxlA== X-Received: by 2002:a05:6808:11ca:b0:3c1:cb6c:8ae5 with SMTP id p10-20020a05680811ca00b003c1cb6c8ae5mr540662oiv.25.1710385478594; Wed, 13 Mar 2024 20:04:38 -0700 (PDT) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id z25-20020aa785d9000000b006e5359e621csm329271pfn.182.2024.03.13.20.04.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 Mar 2024 20:04:37 -0700 (PDT) Date: Wed, 13 Mar 2024 20:04:36 -0700 From: Kees Cook To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Peter Zijlstra Subject: Re: [PATCH 5.15 64/76] proc: Use task_is_running() for wchan in /proc/$pid/stat Message-ID: <202403132003.BF9AF5CA@keescook> References: <20240313164223.615640-1-sashal@kernel.org> <20240313164223.615640-65-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240313164223.615640-65-sashal@kernel.org> On Wed, Mar 13, 2024 at 12:42:11PM -0400, Sasha Levin wrote: > From: Kees Cook > > [ Upstream commit 4e046156792c26bef8a4e30be711777fc8578257 ] > > The implementations of get_wchan() can be expensive. The only information > imparted here is whether or not a process is currently blocked in the > scheduler (and even this doesn't need to be exact). Avoid doing the > heavy lifting of stack walking and just report that information by using > task_is_running(). > > Signed-off-by: Kees Cook > Signed-off-by: Peter Zijlstra (Intel) > Link: https://lkml.kernel.org/r/20211008111626.211281780@infradead.org > Stable-dep-of: 60f92acb60a9 ("fs/proc: do_task_stat: move thread_group_cputime_adjusted() outside of lock_task_sighand()") > Signed-off-by: Sasha Levin Looks fine to me. Can you double-check that commit 54354c6a9f7f ("Revert "proc/wchan: use printk format instead of lookup_symbol_name()"") is already backported too? -- Kees Cook