Re: [PATCH v2 01/10] perf dwarf-aux: Use signed variable types in match_var_offset

[Namhyung Kim <namhyung@kernel.org>]

On Wed, Sep 03, 2025 at 07:05:23PM -0300, Arnaldo Carvalho de Melo wrote:
> On Wed, Sep 03, 2025 at 12:49:49PM -0300, Arnaldo Carvalho de Melo wrote:
> > On Wed, Aug 27, 2025 at 11:52:02PM -0700, Namhyung Kim wrote:
> > > On Mon, Aug 25, 2025 at 07:54:03PM +0000, Zecheng Li wrote:
> > > > match_var_offset compares address offsets to determine if an access
> > > > falls within a variable's bounds. The offsets involved for those
> > > > relative to base registers from DW_OP_breg can be negative.
>  
> > > > The current implementation uses unsigned types (u64) for these offsets,
> > > > which rejects almost all negative values.
>   
> > > Right, I thought it cannot get negative offsets except for stack access
> > > (e.g. fbreg).  But it turns out that container_of() trick can generate
> > > them with optimizing compilers.
>   
> > > > Change the signature of match_var_offset to use signed types (s64). This
> > > > ensures correct behavior when addr_offset or addr_type are negative.
>  
> > > > Signed-off-by: Zecheng Li <zecheng@google.com>
>   
> > > I've confirmed it produced slightly better results on my test sets.
>   
> > > Reviewed-by: Namhyung Kim <namhyung@kernel.org>
>  
> > Cherry picked this first patch to make a bit of progress in the
> > perf-tools-next front.
> 
> It is in perf-tools-next/perf-tools-next now (this first reviewed one):
> 
> https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/log/?h=perf-tools-next

Thanks for doing that.  Please pick up the patch 2 and 3 as well.
Namhyung