From: Namhyung Kim <namhyung@kernel.org>
Date: Wed, 21 Aug 2024 23:26:25 +0000 (-0700)
Subject: perf dwarf-aux: Handle bitfield members from pointer access
X-Git-Tag: v6.10.13~334
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=22f725544b262c5a4d81aace6307ae1ec642d006;p=thirdparty%2Fkernel%2Fstable.git

perf dwarf-aux: Handle bitfield members from pointer access

[ Upstream commit a11b4222bb579dcf9646f3c4ecd2212ae762a2c8 ]

The __die_find_member_offset_cb() missed to handle bitfield members
which don't have DW_AT_data_member_location.  Like in adding member
types in __add_member_cb() it should fallback to check the bit offset
when it resolves the member type for an offset.

Fixes: 437683a9941891c1 ("perf dwarf-aux: Handle type transfer for memory access")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240821232628.353177-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 0e7d2060740df..1b0e59f4d8e93 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -1977,8 +1977,15 @@ static int __die_find_member_offset_cb(Dwarf_Die *die_mem, void *arg)
 		return DIE_FIND_CB_SIBLING;
 
 	/* Unions might not have location */
-	if (die_get_data_member_location(die_mem, &loc) < 0)
-		loc = 0;
+	if (die_get_data_member_location(die_mem, &loc) < 0) {
+		Dwarf_Attribute attr;
+
+		if (dwarf_attr_integrate(die_mem, DW_AT_data_bit_offset, &attr) &&
+		    dwarf_formudata(&attr, &loc) == 0)
+			loc /= 8;
+		else
+			loc = 0;
+	}
 
 	if (offset == loc)
 		return DIE_FIND_CB_END;