From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Date: Mon, 20 Nov 2017 10:49:40 +0000 Subject: Re: [PATCH 1/3] backlight: as3711_bl: fix device-tree node lookup Message-Id: <20171120104940.GC3339@localhost> List-Id: References: <20171113102049.9342-1-johan@kernel.org> <94c3debe-17f6-9151-eefe-129f2bd1cfd4@linaro.org> <20171114180514.GA11226@localhost> <20171115134903.GD11226@localhost> <20171115143211.azfduwkxmzrhlcsd@dell> <20171115143909.GF11226@localhost> In-Reply-To: <20171115143909.GF11226@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Lee Jones Cc: Johan Hovold , Daniel Thompson , Jingoo Han , dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable , Guennadi Liakhovetski On Wed, Nov 15, 2017 at 03:39:09PM +0100, Johan Hovold wrote: > On Wed, Nov 15, 2017 at 02:32:11PM +0000, Lee Jones wrote: > > On Wed, 15 Nov 2017, Johan Hovold wrote: > > > > > On Tue, Nov 14, 2017 at 07:48:09PM +0000, Daniel Thompson wrote: > > > > On 14/11/17 18:05, Johan Hovold wrote: > > > > > On Mon, Nov 13, 2017 at 02:16:09PM +0000, Daniel Thompson wrote: > > > > >> On 13/11/17 10:20, Johan Hovold wrote: > > > > >>> Fix child-node lookup during probe, which ended up searching the whole > > > > >>> device tree depth-first starting at the parent rather than just matching > > > > >>> on its children. > > > > >>> > > > > >>> To make things worse, the parent mfd node was also prematurely freed. > > > > >>> > > > > >>> Note that the nodes returned from the two calls to of_parse_phandle() > > > > >>> are also leaking, but fixing that is a bit more involved as pointers to > > > > >>> node fields are being stored for later use. > > > > >> > > > > >> Is using a devm_kstrdup() to remember the full_name sufficient so get > > > > >> each of the FIXMEs cleaned up as well? > > > > > > > > > > Yeah, that may be sufficient, but looking closer at this now, it seems > > > > > the name pointers (su1_fb and su2_fb) are only used as booleans, and the > > > > > fb_name pointer in struct as3711_bl_data is never used at all. > > > > > > > > > > So cleaning that up somehow (e.g. and maybe even dropping non-dt > > > > > probing) would also work. > > > > > > > > > > But since this is a separate, and less critical issue, I think it needs > > > > > to be done as a follow up to this one. > > > > > > > > To be honest it was adding the separate and less critical FIXMEs into > > > > the patches that attracted my attention in the first place. ;-) > > > > > > Heh. Since I was touching those error paths, I at least wanted to record > > > somehow there were further issues to be addressed. But feel free to drop > > > the FIXMEs if you prefer. > > > > In my experience FIXME's tend not to get addressed: > > > > $ git grep -i fixme | wc -l > > 4431 > > > > Submit patches instead. :) > > There may be some truth to that, but I still think it's better to mark > what is broken (especially since a leaked node is no big deal in this > case) than to just ignore and forget about it. I just sent a v2 including a new patch fixing these node leaks instead of just flagging them. The driver really had no business storing those node full_name fields in the first place. Johan