Re: [PATCH 4.14 29/72] locking/qspinlock, x86: Provide liveness guarantee

[Sebastian Andrzej Siewior]

On 2018-12-20 18:49:41 [+0000], Sudip Mukherjee wrote:
> On Thu, Dec 20, 2018 at 04:40:30PM +0100, Greg Kroah-Hartman wrote:
> > On Thu, Dec 20, 2018 at 12:14:00PM +0000, Sudip Mukherjee wrote:
> > > Hi Greg,
> > > 
> > > On Thu, Dec 20, 2018 at 9:28 AM Greg Kroah-Hartman
> > > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > > >
> > > > 4.14-stable review patch.  If anyone has any objections, please let me know.
> > > >
> > > > ------------------
> > > >
> > > > commit 7aa54be2976550f17c11a1c3e3630002dea39303 upstream.
> > > 
> > > Another upstream commit fixes this.
> > > b987ffc18fb3 ("x86/qspinlock: Fix compile error")
> > 
> > Maybe, but that commit doesn't apply to any of these stable trees :(
> > 
> > Care to provide a backport?
> 
> Attached now.

Are you sure that it fails to compile without that patch? I have here
Debian's gcc version 8.2.0 which probably isn't affected and I can
compile kernel/locking/ in v4.19 + 4.14.

I'm asking because in my backport the GEN_BINARY_RMWcc macro is used
like in all the other functions which use it - unlike like in the
original commit where the macro is used directly in the if condition. So
it  might not be affected by the problem.

Therefore I would prefer not to try to patch something that isn't
required.

> --
> Regards
> Sudip

Sebastian