From mboxrd@z Thu Jan 1 00:00:00 1970 From: mpa@pengutronix.de (Markus Pargmann) Date: Thu, 27 Aug 2015 07:49:25 +0200 Subject: [PATCH] regmap: Fix the null function of format_val on regmap_bulk_read. In-Reply-To: <20150826173812.GA28760@sirena.org.uk> References: <1440589396-696-1-git-send-email-henryc.chen@mediatek.com> <20150826123556.GB2977@sirena.org.uk> <20150826132246.GR706@pengutronix.de> <20150826173812.GA28760@sirena.org.uk> Message-ID: <20150827054925.GK706@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Aug 26, 2015 at 06:38:12PM +0100, Mark Brown wrote: > On Wed, Aug 26, 2015 at 03:22:46PM +0200, Markus Pargmann wrote: > > On Wed, Aug 26, 2015 at 01:35:56PM +0100, Mark Brown wrote: > > > On Wed, Aug 26, 2015 at 07:43:16PM +0800, Henry Chen wrote: > > > > Why are these format functions sensible? Converting a null pointer > > > dereference into data corruption wouldn't be ideal. The commit message > > > should really cover this. > > > The regmap_bulk_read() function worked before the following patch: > > 15b8d2c41fe5 (regmap: Fix regmap_bulk_read in BE mode) > > Define "worked" here. "worked" means here that it did not run into a null pointer and returned something that the user expected. I am not sure if someone actually complained about the previous use of memcpy? I also don't know how the behavior of regmap_bulk_read with reg_read() is defined. Best Regards, Markus > > > As far as I can see this patch fixes this issue by using simple format > > functions. Before the above mentioned patch, the code used memcpy. Now > > regmap_format_*_native is used which should result in the same behaviour > > but fixes the null pointer. > > Again, this sort of analysis needs to be in the commit message (and > really ought to explain why the resulting API makes sense). > > > I am not sure if there are other locations in the code where format_val > > is used in this setup so I don't know if this would change behavior in a > > different codepath. > > Which is another part of the concern, being able to format values is a > more general concept. -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: