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 0ACBA14F6C for ; Fri, 9 Feb 2024 22:13:25 +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=1707516806; cv=none; b=RjBhd+X5/RdYO5qRN3jtsMTZ0NS1I0atMzURgXn2R3Csi3Fg8nTgcArXASW4HSCUGoZwSsvT4yWrpblgvI/t4xo9FNuQReh/zPZxsxh2XXk7calXBZz8tPoSbdm4p+ZaULOZ+4oP+T+yX6ruyHPFVDWzOIQuneZFdn4ny4TCHoI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707516806; c=relaxed/simple; bh=xDYbd+DGzLF4NRgDCcI5oy/Gg3q6BXcvRGOTITka09Y=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=s/NvDt/YnETVp98LfHCIyyrbZrlycrMkzwzrWB39eQMsCcDSv7A8i/4xyBCfWI6T5UBzASUBf3u3YB60tHIM7npo9A3Wl+C6IVKc3/CRvTCRj00tc0Fsz45qJhUtb1sx7vAiBVt0YJlY8mRP519vOsl+jlC1QaUGw3inWBiigyk= 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=jZZYKmSZ; 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="jZZYKmSZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A3EFC433C7; Fri, 9 Feb 2024 22:13:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1707516805; bh=xDYbd+DGzLF4NRgDCcI5oy/Gg3q6BXcvRGOTITka09Y=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=jZZYKmSZwEVkeSNrzlDR/rmu9PIg6eib8zzw63E+9YVy0+ptXVUMMNZgN29G3b3tJ dtdMHi8RdCi30sdnA3CJ4rie0jgstN9FqPdcn1oHtARMbtbOMa34GCjjLB6WVKn1mE SXc0T/75Fv/GWI74oE7HEcx5Ll1zfrfnw2+lwMbo= Date: Fri, 9 Feb 2024 14:13:24 -0800 From: Andrew Morton To: Kent Overstreet Cc: linux-kernel@vger.kernel.org, fuyuanli Subject: Re: [PATCH] kernel/hung_task.c: export sysctl_hung_task_timeout_secs Message-Id: <20240209141324.28cae36fe14c909058c1fed7@linux-foundation.org> In-Reply-To: <20240209070935.1529844-1-kent.overstreet@linux.dev> References: <20240209070935.1529844-1-kent.overstreet@linux.dev> 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 Fri, 9 Feb 2024 02:09:35 -0500 Kent Overstreet wrote: > needed for thread_with_file; also rare but not unheard of to need this > in module code, when blocking on user input. I see no bcachefs code in linux-next which uses this. All I have to go with is the above explanation-free assertion. IOW this patch is unreviewable. > one workaround used by some code is wait_event_interruptible() examples? > - but that can be buggy if the outer context isn't expecting unwinding. More explanation of this? > --- a/kernel/hung_task.c > +++ b/kernel/hung_task.c > @@ -43,6 +43,7 @@ static int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT; > * Zero means infinite timeout - no checking done: > */ > unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_TASK_TIMEOUT; > +EXPORT_SYMBOL_GPL(sysctl_hung_task_timeout_secs); It seems strange that a module wouild want this. Makes one wonder what the heck is going on in there.