Patch "perf intel-pt: Fix unassigned instruction op (discovered by MemorySanitizer)" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    perf intel-pt: Fix unassigned instruction op (discovered by MemorySanitizer)

to the 5.15-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-intel-pt-fix-unassigned-instruction-op-discover.patch
and it can be found in the queue-5.15 subdirectory.

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



commit ecad851e518d9aa4eeb34a3f676c8d3f2123117d
Author: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Date:   Tue Mar 26 10:32:23 2024 +0200

    perf intel-pt: Fix unassigned instruction op (discovered by MemorySanitizer)
    
    [ Upstream commit e101a05f79fd4ee3e89d2f3fb716493c33a33708 ]
    
    MemorySanitizer discovered instances where the instruction op value was
    not assigned.:
    
      WARNING: MemorySanitizer: use-of-uninitialized-value
        #0 0x5581c00a76b3 in intel_pt_sample_flags tools/perf/util/intel-pt.c:1527:17
      Uninitialized value was stored to memory at
        #0 0x5581c005ddf8 in intel_pt_walk_insn tools/perf/util/intel-pt-decoder/intel-pt-decoder.c:1256:25
    
    The op value is used to set branch flags for branch instructions
    encountered when walking the code, so fix by setting op to
    INTEL_PT_OP_OTHER in other cases.
    
    Fixes: 4c761d805bb2d2ea ("perf intel-pt: Fix intel_pt_fup_event() assumptions about setting state type")
    Reported-by: Ian Rogers <irogers@xxxxxxxxxx>
    Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
    Tested-by: Ian Rogers <irogers@xxxxxxxxxx>
    Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
    Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
    Closes: https://lore.kernel.org/linux-perf-users/20240320162619.1272015-1-irogers@xxxxxxxxxx/
    Link: https://lore.kernel.org/r/20240326083223.10883-1-adrian.hunter@xxxxxxxxx
    Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
index b9f94f198a3eb..3530551b82819 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -1215,6 +1215,8 @@ static bool intel_pt_fup_event(struct intel_pt_decoder *decoder)
 	bool ret = false;
 
 	decoder->state.type &= ~INTEL_PT_BRANCH;
+	decoder->state.insn_op = INTEL_PT_OP_OTHER;
+	decoder->state.insn_len = 0;
 
 	if (decoder->set_fup_tx_flags) {
 		decoder->set_fup_tx_flags = false;
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 805bad9364e94..b00776c65c186 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -721,6 +721,7 @@ static int intel_pt_walk_next_insn(struct intel_pt_insn *intel_pt_insn,
 	bool nr;
 
 	intel_pt_insn->length = 0;
+	intel_pt_insn->op = INTEL_PT_OP_OTHER;
 
 	if (to_ip && *ip == to_ip)
 		goto out_no_cache;
@@ -816,6 +817,7 @@ static int intel_pt_walk_next_insn(struct intel_pt_insn *intel_pt_insn,
 
 			if (to_ip && *ip == to_ip) {
 				intel_pt_insn->length = 0;
+				intel_pt_insn->op = INTEL_PT_OP_OTHER;
 				goto out_no_cache;
 			}