[PATCH 5.4 6/7] perf unwind: Set userdata for all __report_module() paths

[Greg Kroah-Hartman]

From: Dave Rigby <d.rigby@xxxxxx>

commit 4e1481445407b86a483616c4542ffdc810efb680 upstream.

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")
Signed-off-by: Dave Rigby <d.rigby@xxxxxx>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211801
Acked-by: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: https://lore.kernel.org/linux-perf-users/20210218165654.36604-1-d.rigby@xxxxxx/
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: "Tommi Rantala" <tommi.t.rantala@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 tools/perf/util/unwind-libdw.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/tools/perf/util/unwind-libdw.c
+++ b/tools/perf/util/unwind-libdw.c
@@ -60,10 +60,8 @@ static int __report_module(struct addr_l
 	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_l
 					      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;
 }