Re: [PATCH 1/5] radix tree test suite: fix mapshift build target

[Ross Zwisler]

On Sun, Jul 22, 2018 at 09:45:50AM +1000, Dave Chinner wrote:
> On Mon, Jul 16, 2018 at 07:41:32PM -0700, Matthew Wilcox wrote:
> > On Mon, Jul 16, 2018 at 03:08:20PM -0600, Ross Zwisler wrote:
> > > On Mon, Jul 16, 2018 at 12:52:49PM -0700, Matthew Wilcox wrote:
> > > > On Mon, Jul 16, 2018 at 10:07:10AM -0600, Ross Zwisler wrote:
> > > <>
> > > > OK ... what version of make are you using?  Because this works fine for me:
> > > > 
> > > > $ git clone linux clean
> > > > $ cd clean
> > > > $ git checkout v4.17
> > > > $ cd tools/testing/radix-tree/ 
> > > > $ git revert 8d9fa88edd5e360b71765feeadb915d4066c9684
> > > > $ make
> > > > 
> > > > $ make --version
> > > > GNU Make 4.1
> > > > Built for x86_64-pc-linux-gnu
> > > > 
> > > > It's Debian's Version: 4.1-9.1
> > > 
> > > $ make --version
> > > GNU Make 4.2.1
> > > Built for x86_64-redhat-linux-gnu
> > > 
> > > The one from Fedora 27.
> > 
> > Huh.  I just tried 4.2.1-1.1 from Debian unstable and that doesn't
> > produce the problem either.  I'm not sure how to proceed at this point.
> > I'm really not a makefile expert.
> 
> This smells like a problem we just hit with make 4.2.1 in fedora 28
> in fstests - the regex expanstion has been screwed up such that
> things like [a-z] will match [A-Z] and other things as well. Debian
> is unaffected, apparently fedora has a backport of stuff from the
> as-yet-unreleased next version of make/glibc. See this thread:
> 
> https://www.spinics.net/lists/fstests/msg10200.html
> 
> Try setting LANG=C and seeing if the problem goes away....

Hey Dave, we root caused this difference to to be the fact that I had 'make'
aliased to 'make -j32' in my .bashrc.  Matthew was running a singled threaded
build, while I was running a multi-threaded one.  When Matthew ran a
multi-threaded build, he was able to reproduce the issue.

So, essentially I think that the makefile just needs to be enhanced so that
all the dependencies are explicit to allow multi-threaded builds to work
properly.