Re: [bitbake-devel] [PATCH 2/2] fetch2: Fix race condition in latest_revision

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Fri, 2021-11-05 at 14:30 +0100, Jasper Orschulko via lists.openembedded.org
wrote:
> From: Martin Koppehel <martin@mko.dev>
> 
> Setting latest_revision contained a race condition, where it would be
> set to an empty string, if the hash calculation function would take to
> long.
> 
> Signed-off-by: Jasper Orschulko <Jasper.Orschulko@iris-sensing.com>
> ---
>  lib/bb/fetch2/__init__.py | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/bb/fetch2/__init__.py b/lib/bb/fetch2/__init__.py
> index 6a38cb09..9dc23d05 100644
> --- a/lib/bb/fetch2/__init__.py
> +++ b/lib/bb/fetch2/__init__.py
> @@ -1602,7 +1602,9 @@ class FetchMethod(object):
>          try:
>              return revs[key]
>          except KeyError:
> -            revs[key] = rev = self._latest_revision(ud, d, name)
> +            rev = self._latest_revision(ud, d, name)
> +            if rev != '':
> +                revs[key] = rev
>              return rev
>  
>      def sortable_revision(self, ud, d, name):

I'm afraid I don't understand why this is a race condition? Where is the timeout
that stops one being set?

Cheers,

Richard