Re: [OE-core][PATCH v5] kernel.bbclass: make do_symlink_kernelsrc reentrant

[Alexandre Belloni <alexandre.belloni@bootlin.com>]

On 27/05/2024 11:45:58+0200, Etienne Cordonnier via lists.openembedded.org wrote:
> Hi Richard,
> 
> I also apologize for replying late. I was busy with other things and
> haven't found time to rework this patch.
> 
> > Firstly, can I ask why you're using a non-default directory for ${S}?
> > Is this as a way of doing a kind of external source usage?
> 
> My use-case is that the BSP I am using includes the source of the kernel as
> source alongside the BSP yocto layer (not in an extra git repository), and
> then points S to the directory containing the sources of the kernel without
> using the externalsrc class (as far as I know the externalsrc class isn't
> meant for this use-case, since there are several recipes provided as source
> in this way, and externalsrc only has one path pointing to the external
> source).
> 

You should rather educate your vendor to provide a proper git repository
for the kernel.

> I agree with you that the complexity of this function is very high, so not
> supporting a non-default S would be a better solution in this case. I'll
> try to rework the patch and test it with externalsrc as well.
> 
> Étienne
> 
> On Fri, Feb 9, 2024 at 6:36 PM Richard Purdie <
> richard.purdie@linuxfoundation.org> wrote:
> 
> > On Thu, 2023-12-21 at 22:49 +0100, Etienne Cordonnier via
> > lists.openembedded.org wrote:
> > > From: Etienne Cordonnier <ecordonnier@snap.com>
> > >
> > > The function do_symlink_kernsrc is not reentrant in the case where S is
> > defined
> > > to a non-default value. This causes build-failures e.g. when building
> > linux-yocto, then updating
> > > poky to a commit which modifies kernel.bbclass, and then building
> > linux-yocto again.
> > >
> > > Bugzilla:
> > https://urldefense.proofpoint.com/v2/url?u=https-3A__bugzilla.yoctoproject.org_show-5Fbug.cgi-3Fid-3D15325&d=DwIFaQ&c=ncDTmphkJTvjIDPh0hpF_4vCHvabgGkICC2epckfdiw&r=AhkbNonVuMIGRfPx_Qj9TsRih1DULJTKUkSGa66m67E&m=e0iYk69Iih3UnIjABITtc6yS38bhv_6P4NMuSpVmmoSHk1-sSuvH3y702O0nTeZj&s=OtiPnSuoZjUXFgz9pxbGOOyjQmKPEq-OhEbhtsAmvZE&e=
> > >
> > > Tested with a recipe "my-custom-linux" which unpacks sources to a custom
> > ${S} directory
> > > and ran symlink_kernsrc several times:
> > > $ bitbake -f -c symlink_kernsrc my-custom-linux
> >
> > Sorry for the delay in getting back to review this patch. I'm extremely
> > worried about adding complexity into this function, particularly as
> > that complexity is now adding in significant overhead.
> >
> > Firstly, can I ask why you're using a non-default directory for ${S}?
> > Is this as a way of doing a kind of external source usage?
> >
> > Having spent time looking at what this code is doing, in normal usage,
> > S gets set to STAGING_KERNEL_DIR, the source is unpacked there and none
> > of this code triggers.
> >
> > For EXTERNALSRC, a symlink is put in place. The code should remove a
> > symlink if present and create it with the current setup. In that sense,
> > this patch isn't doing the right thing.
> >
> > I'm very tempted to say the "using a non default S value" just error
> > out.
> >
> > Whilst I understand how we got to this level of complexity, I think it
> > will just end up causing us pain in the long run and I'd rather just
> > not support it.
> >
> > Cheers,
> >
> > Richard
> >

> 
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Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com