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 AD9E12F39C7 for ; Wed, 13 Aug 2025 22:01:56 +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=1755122516; cv=none; b=bnDN93ND8ea/Z4eV6vvw5SDfOWXkvJIWASxRjbOQwTY2ACvaenyMx6YqUev+JPTBCiMPsfXsRa+VR0RCbwSNfjvWzVLae9LKTRb5grCaIul0EYrbJ1Of1V5zrq6aBbC5C7ev/2u9ZwxmWSg7/ewuAbDp69wKopD2qsLIwaUcniw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755122516; c=relaxed/simple; bh=yPLTIGHkAU48mMe7a/YMASqRcP4ZP+4xEDN+XqrQ+Tk=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=UyUix8oGtWDnZjOP5KNupACwnZ9b71+4tKvlmJZ4p65p310+rWuH04M42I747EE0EqDxlaWiLU2DXoVScwQN4f3u4WL4mb5k9n56lvvXxOd7WBycnlwUNN+2DKGOwpEbjWKEZfr20Baszneb6zIVGBNvyMfiPbzi0MniHWsvqac= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=VORMbbAl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="VORMbbAl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09A4DC4CEEB; Wed, 13 Aug 2025 22:01:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1755122516; bh=yPLTIGHkAU48mMe7a/YMASqRcP4ZP+4xEDN+XqrQ+Tk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=VORMbbAl+fY/DGJKEtsNj3CarhAjUkUxQLManmah3KztYjAPI5UkeL+rZxVD4VWyN n/8UdnrzALINZ5B2PWcCQilOujvVG71jcFZ5WuBrDKrp1ZG5ttRBqwONoGBide7xQf yDlQhqPHByCBoP5cYfSsXGaCkSyTXxndfuN7WopE= Date: Wed, 13 Aug 2025 15:01:55 -0700 From: Andrew Morton To: "Nanji Parmar (he/him)" Cc: lance.yang@linux.dev, mhiramat@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] hung_task: Skip hung task detection during core dump operations Message-Id: <20250813150155.81680178704c4652fd454a80@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 13 Aug 2025 11:30:36 -0700 "Nanji Parmar (he/him)" wrote: > Tasks involved in core dump operations can legitimately block for > extended periods, especially for large memory processes. The hung > task detector should skip tasks with PF_DUMPCORE (main dumping > thread) or PF_POSTCOREDUMP (other threads in the group) flags to > avoid false positive warnings. > > This prevents incorrect hung task reports during legitimate core > dump generation that can take xx minutes for large processes. It isn't pleasing to be putting coredump special cases into the core of the hung-task detector. Perhaps the hung task detector should get an equivalent to touch_softlockup_watchdog(). I'm surprised it doesn't already have such a thing. Maybe it does and I've forgotten where it is. Please provide a full description of the problem, mainly the relevant dmesg output. Please always provide this full description when addressing kernel issues, thanks.