Patch "perf dwarf-aux: Handle bitfield members from pointer access" has been added to the 6.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    perf dwarf-aux: Handle bitfield members from pointer access

to the 6.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-dwarf-aux-handle-bitfield-members-from-pointer-.patch
and it can be found in the queue-6.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 88af328ccb862d7065a262fe4225195284c03459
Author: Namhyung Kim <namhyung@xxxxxxxxxx>
Date:   Wed Aug 21 16:26:25 2024 -0700

    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@xxxxxxxxxx>
    Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
    Cc: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
    Cc: Ian Rogers <irogers@xxxxxxxxxx>
    Cc: Ingo Molnar <mingo@xxxxxxxxxx>
    Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
    Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
    Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
    Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
    Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240821232628.353177-2-namhyung@xxxxxxxxxx
    Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

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;