Re: [PATCH] dpkg-base: cope with race around check/creation of .git-downloads symlink

[Cedric Hombourger <Cedric_Hombourger@mentor.com>]

On Wed, 2022-02-02 at 08:05 +0100, Jan Kiszka wrote:
> On 01.02.22 14:41, Cedric Hombourger wrote:
> > There is a race condition between the check for the .git-downloads
> > symbolic
> > link existing and its creation. Ignore the FileExistsError
> > exception when
> > hitting this race.
> > 
> > Signed-off-by: Cedric Hombourger <Cedric_Hombourger@mentor.com>
> > ---
> >  meta/classes/dpkg-base.bbclass | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/meta/classes/dpkg-base.bbclass b/meta/classes/dpkg-
> > base.bbclass
> > index 2add0b2..3aa52b1 100644
> > --- a/meta/classes/dpkg-base.bbclass
> > +++ b/meta/classes/dpkg-base.bbclass
> > @@ -23,7 +23,10 @@ python do_adjust_git() {
> >      git_dl = os.path.join(d.getVar("DL_DIR"), "git")
> >  
> >      if not os.path.exists(git_link) or os.path.realpath(git_link)
> > != git_dl:
> > -        os.symlink(git_dl, git_link)
> > +        try:
> > +            os.symlink(git_dl, git_link)
> > +        except FileExistsError:
> > +            pass
> >  
> >      for src_uri in (d.getVar("SRC_URI", True) or "").split():
> >          try:
> 
> do_adjust_git is run under global ${DL_DIR}/git/isar.lock - how do
> you
> trigger this race then?

good catch. I had not noticed this lock. I have been getting this
exception while building on a machine with many CPUs (32 IIRC). I have
no idea how this could happen with this lock held. Going to debug
further. Thanks for the pointer

> 
> Jan
>