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 D0AE51EB3B for ; Sat, 25 Nov 2023 19:29:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BFVN7MV2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1BA97C433C8; Sat, 25 Nov 2023 19:29:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700940552; bh=T9ybAOqdYbePgwxUcm0MrumA2w7ABJfsHzDYHj7SqKQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BFVN7MV2Y/JG6IVN4YyAmqIrmLQmKorlO5J9sbOtBeOuXALW2jxWNWfO9K7HyyqTV 3AAgjmxIgRS9904e3OM972kEl0kCcX1udmWXP+fIUJE4RAOvztfkoHEn8NB+rztkXH BsaAtZ2RpVxYYTzKs8l2+wmubXYxSSMGUju83la0= Date: Sat, 25 Nov 2023 19:29:10 +0000 From: Greg Kroah-Hartman To: Johannes Berg Cc: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" Subject: Re: [PATCH v2 1/6] debugfs: fix automount d_fsdata usage Message-ID: <2023112555-squabble-ended-6b8d@gregkh> References: <20231124162522.16344-7-johannes@sipsolutions.net> <20231124172522.01928f127e73.I64fe5615568e87f9ae2d7fb2ac4e5fa96924cb50@changeid> <2023112519-reprocess-backtrack-0732@gregkh> Precedence: bulk X-Mailing-List: linux-wireless@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: On Sat, Nov 25, 2023 at 07:31:47PM +0100, Johannes Berg wrote: > On Sat, 2023-11-25 at 14:48 +0000, Greg Kroah-Hartman wrote: > > On Fri, Nov 24, 2023 at 05:25:24PM +0100, Johannes Berg wrote: > > > From: Johannes Berg > > > > > > debugfs_create_automount() stores a function pointer in d_fsdata, > > > but since commit 7c8d469877b1 ("debugfs: add support for more > > > elaborate ->d_fsdata") debugfs_release_dentry() will free it, now > > > conditionally on DEBUGFS_FSDATA_IS_REAL_FOPS_BIT, but that's not > > > set for the function pointer in automount. As a result, removing > > > an automount dentry would attempt to free the function pointer. > > > Luckily, the only user of this (tracing) never removes it. > > > > > > Nevertheless, it's safer if we just handle the fsdata in one way, > > > namely either DEBUGFS_FSDATA_IS_REAL_FOPS_BIT or allocated. Thus, > > > change the automount to allocate it, and use the real_fops in the > > > data to indicate whether or not automount is filled, rather than > > > adding a type tag. At least for now this isn't actually needed, > > > but the next changes will require it. > > > > > > Also check in debugfs_file_get() that it gets only called > > > on regular files, just to make things clearer. > > > > > > Signed-off-by: Johannes Berg > > > --- > > > v2: add missing kfree() pointed out by smatch > > > > Acked-by: Greg Kroah-Hartman > > I have to fix the Kconfig issue in one of the later (wireless) patches, > but does that mean you'd actually prefer the debugfs changes go through > the wireless tree, together with the code using it? I'm all for you taking these through the wireless tree, have fun! greg k-h