Re: [PATCH] perf unwind: Set userdata for all __report_module paths

[Dave Rigby <d.rigby@me.com>]

I missed adding a link to the bugzilla issue: https://bugzilla.kernel.org/show_bug.cgi?id=211801

Note sure what the recommended way of tagging that in the patch is…


DaveR

> On 18 Feb 2021, at 16:56, d.rigby@me.com wrote:
> 
> From: Dave Rigby <d.rigby@me.com>
> 
> When locating the dwarf module for a given address, __find_debuginfo()
> requires a 'struct dso' passed via the userdata argument.
> 
> However, this field is only set in __report_module() if the module is
> found in via dwfl_addrmodule(), not if it is found later via dwfl_report_elf().
> 
> Set userdata irrespective of how the dwarf module was found, as long
> as we found a module.
> 
> Fixes: bf53fc6b5f41 ("perf unwind: Fix separate debug info files when using elfutils' libdw's unwinder")
> Cc: linux-perf-users@vger.kernel.org
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
> Cc: Jiri Olsa <jolsa@redhat.com>
> ---
> tools/perf/util/unwind-libdw.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
> index 0ada907..a74b517 100644
> --- a/tools/perf/util/unwind-libdw.c
> +++ b/tools/perf/util/unwind-libdw.c
> @@ -60,10 +60,8 @@ static int __report_module(struct addr_location *al, u64 ip,
> 	mod = dwfl_addrmodule(ui->dwfl, ip);
> 	if (mod) {
> 		Dwarf_Addr s;
> -		void **userdatap;
> 
> -		dwfl_module_info(mod, &userdatap, &s, NULL, NULL, NULL, NULL, NULL);
> -		*userdatap = dso;
> +		dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL);
> 		if (s != al->map->start - al->map->pgoff)
> 			mod = 0;
> 	}
> @@ -79,6 +77,13 @@ static int __report_module(struct addr_location *al, u64 ip,
> 					      al->map->start - al->map->pgoff, false);
> 	}
> 
> +	if (mod) {
> +		void **userdatap;
> +
> +		dwfl_module_info(mod, &userdatap, NULL, NULL, NULL, NULL, NULL, NULL);
> +		*userdatap = dso;
> +	}
> +
> 	return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
> }
> 
> -- 
> 1.8.3.1