LTS perf unwind fix

LTS perf unwind fix

[Rantala, Tommi T. (Nokia - FI/Espoo)]

Hi Greg,

Can you please cherry-pick this to LTS:

commit bf53fc6b5f415cddc7118091cb8fd6a211b2320d
Author: Jan Kratochvil <jan.kratochvil@redhat.com>
Date:   Fri Dec 4 09:17:02 2020 -0300

    perf unwind: Fix separate debug info files when using elfutils' libdw's unwinder


-Tommi

Re: LTS perf unwind fix

[Jan Kratochvil]

On Tue, 25 May 2021 14:41:15 +0200, Rantala, Tommi T. (Nokia - FI/Espoo) wrote:
> Can you please cherry-pick this to LTS:
> 
> commit bf53fc6b5f415cddc7118091cb8fd6a211b2320d
> Author: Jan Kratochvil <jan.kratochvil@redhat.com>
> Date:   Fri Dec 4 09:17:02 2020 -0300
> 
>     perf unwind: Fix separate debug info files when using elfutils' libdw's unwinder

It needs to be cherry-picked together with this commit as my commit did cause
a regression:

commit 4e1481445407b86a483616c4542ffdc810efb680
Author: Dave Rigby <d.rigby@me.com>
Date:   Thu Feb 18 16:56:54 2021 +0000

    perf unwind: Set userdata for all __report_module() paths


Jan Kratochvil

Re: LTS perf unwind fix

[gregkh]

On Tue, May 25, 2021 at 12:41:15PM +0000, Rantala, Tommi T. (Nokia - FI/Espoo) wrote:
> Hi Greg,
> 
> Can you please cherry-pick this to LTS:
> 
> commit bf53fc6b5f415cddc7118091cb8fd6a211b2320d
> Author: Jan Kratochvil <jan.kratochvil@redhat.com>
> Date:   Fri Dec 4 09:17:02 2020 -0300
> 
>     perf unwind: Fix separate debug info files when using elfutils' libdw's unwinder

What exact kernel(s) do you want it backported to?

thanks,

greg k-h

Re: LTS perf unwind fix

[Rantala, Tommi T. (Nokia - FI/Espoo)]

2021-05-25 15:06 +0200, gregkh@linuxfoundation.org:
> On Tue, May 25, 2021 at 12:41:15PM +0000, Rantala, Tommi T. (Nokia -
> FI/Espoo) wrote:
> > Can you please cherry-pick this to LTS:
> > 
> > commit bf53fc6b5f415cddc7118091cb8fd6a211b2320d
> > Author: Jan Kratochvil <jan.kratochvil@redhat.com>
> > Date:   Fri Dec 4 09:17:02 2020 -0300
> > 
> >     perf unwind: Fix separate debug info files when using elfutils'
> > libdw's unwinder
> 
> What exact kernel(s) do you want it backported to?

5.4.y please, tested Jan's and Dave's patches with it, and they cure
some broken backtraces.


  commit 4e1481445407b86a483616c4542ffdc810efb680
  Author: Dave Rigby <d.rigby@me.com>
  Date:   Thu Feb 18 16:56:54 2021 +0000

    perf unwind: Set userdata for all __report_module() paths

Re: LTS perf unwind fix

[gregkh]

On Wed, May 26, 2021 at 07:21:15AM +0000, Rantala, Tommi T. (Nokia - FI/Espoo) wrote:
> 2021-05-25 15:06 +0200, gregkh@linuxfoundation.org:
> > On Tue, May 25, 2021 at 12:41:15PM +0000, Rantala, Tommi T. (Nokia -
> > FI/Espoo) wrote:
> > > Can you please cherry-pick this to LTS:
> > > 
> > > commit bf53fc6b5f415cddc7118091cb8fd6a211b2320d
> > > Author: Jan Kratochvil <jan.kratochvil@redhat.com>
> > > Date:   Fri Dec 4 09:17:02 2020 -0300
> > > 
> > >     perf unwind: Fix separate debug info files when using elfutils'
> > > libdw's unwinder
> > 
> > What exact kernel(s) do you want it backported to?
> 
> 5.4.y please, tested Jan's and Dave's patches with it, and they cure
> some broken backtraces.
> 
> 
>   commit 4e1481445407b86a483616c4542ffdc810efb680
>   Author: Dave Rigby <d.rigby@me.com>
>   Date:   Thu Feb 18 16:56:54 2021 +0000
> 
>     perf unwind: Set userdata for all __report_module() paths
> 
> 

What does this commit here have to do with the above?

confused as to what exactly you are asking for here, sorry, can you be
more specific?  Like "please apply commits X, Y, and Z, in that order,
to the X.y kernel?"

thanks,

greg k-h

Re: LTS perf unwind fix

[Rantala, Tommi T. (Nokia - FI/Espoo)]

Hi Greg,

Please apply these two commits to 5.4.y
(other LTSes are probably fine too, but I didn't test):


commit bf53fc6b5f415cddc7118091cb8fd6a211b2320d
Author: Jan Kratochvil <jan.kratochvil@redhat.com>
Date:   Fri Dec 4 09:17:02 2020 -0300

    perf unwind: Fix separate debug info files when using elfutils'
libdw's unwinder


commit 4e1481445407b86a483616c4542ffdc810efb680
Author: Dave Rigby <d.rigby@me.com>
Date:   Thu Feb 18 16:56:54 2021 +0000

    perf unwind: Set userdata for all __report_module() paths

    [...]

    Fixes: bf53fc6b5f41 ("perf unwind: Fix separate debug info files
when using elfutils' libdw's unwinder")


These commits fix some broken backtraces when using the perf tool.

Thanks!
-Tommi

Re: LTS perf unwind fix

[gregkh]

On Thu, May 27, 2021 at 10:04:51AM +0000, Rantala, Tommi T. (Nokia - FI/Espoo) wrote:
> Hi Greg,
> 
> Please apply these two commits to 5.4.y
> (other LTSes are probably fine too, but I didn't test):
> 
> 
> commit bf53fc6b5f415cddc7118091cb8fd6a211b2320d
> Author: Jan Kratochvil <jan.kratochvil@redhat.com>
> Date:   Fri Dec 4 09:17:02 2020 -0300
> 
>     perf unwind: Fix separate debug info files when using elfutils'
> libdw's unwinder
> 
> 
> commit 4e1481445407b86a483616c4542ffdc810efb680
> Author: Dave Rigby <d.rigby@me.com>
> Date:   Thu Feb 18 16:56:54 2021 +0000
> 
>     perf unwind: Set userdata for all __report_module() paths
> 
>     [...]
> 
>     Fixes: bf53fc6b5f41 ("perf unwind: Fix separate debug info files
> when using elfutils' libdw's unwinder")
> 
> 
> These commits fix some broken backtraces when using the perf tool.

Also queued up for the 5.10.y tree as you do not want to move to a newer
kernel and have a regression.

thanks,

greg k-h