On Tue, May 22, 2018 at 09:37:39AM +0000, Fabrizio Castro wrote: > Hello Greg, > > Thank you for your feedback. > > > Subject: Re: [PATCH] dmaengine: ensure dmaengine helpers check valid callback > > > > On Mon, May 21, 2018 at 05:56:55PM +0100, Fabrizio Castro wrote: > > > From: Vinod Koul <vinod.koul@xxxxxxxxx> > > > > > > commit 757d12e5849be549076901b0d33c60d5f360269c upstream. > > > > > > dmaengine has various device callbacks and exposes helper > > > functions to invoke these. These helpers should check if channel, > > > device and callback is valid or not before invoking them. > > > > > > Reported-by: Jon Hunter <jonathanh@xxxxxxxxxx> > > > Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx> > > > [fabrizio: cherry-pick to 4.4] > > > Signed-off-by: Fabrizio Castro <fabrizio.castro@xxxxxxxxxxxxxx> > > > Signed-off-by: Jianming Qiao <jianming.qiao@xxxxxxxxxxxxxx> > > > --- > > > Hello Greg, > > > > > > while backporting commit 757d12e5849be549076901b0d33c60d5f360269c > > > to the CIP kernel Ben recommended to send the same patch to you > > > for 4.4 stable. > > > I hope the format of the commit is the one you expect (reference to > > > the upstream commit, version to cherry-pick the patch to, and > > > Signed-off-by tags). > > > > Format is fine, but why is this needed in the 4.4.y kernel tree? > > We work with the CIP kernel (v4.4), and from time to time we come across bug fixes we feel like stable could benefit from. > Also, since Ben merges the CIP branch with stable, the fixes we make to stable will appear in the CIP kernel too at some point. > If you feel like the patch is not worth considering for stable, it can still be applied to the CIP kernel if required. > Ben has already taken this patch (for v4.4.126-cip22) therefore it's not on our critical path, but it would be nice to have in the stable kernel too. > > > What bug does it solve? > > Without this patch we managed to get the kernel to try and dereference > a NULL pointer while playing around with ttys (basically by having the > wrong tty with /etc/securetty). Really? What tty caused this problem? > Are you happy to take this patch? It does not seem to fix a problem in the tree today, but it feels "safe enough", so I guess I'll queue it up. thanks, greg k-h
