6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Namhyung Kim <namhyung@xxxxxxxxxx>
commit 9af2efee41b27a0f386fb5aa95d8d0b4b5d9fede upstream.
The fields in the hist_entry are filled on-demand which means they only
have meaningful values when relevant sort keys are used.
So if neither of 'dso' nor 'sym' sort keys are used, the map/symbols in
the hist entry can be garbage. So it shouldn't access it
unconditionally.
I got a segfault, when I wanted to see cgroup profiles.
$ sudo perf record -a --all-cgroups --synth=cgroup true
$ sudo perf report -s cgroup
Program received signal SIGSEGV, Segmentation fault.
0x00005555557a8d90 in map__dso (map=0x0) at util/map.h:48
48 return RC_CHK_ACCESS(map)->dso;
(gdb) bt
#0 0x00005555557a8d90 in map__dso (map=0x0) at util/map.h:48
#1 0x00005555557aa39b in map__load (map=0x0) at util/map.c:344
#2 0x00005555557aa592 in map__find_symbol (map=0x0, addr=140736115941088) at util/map.c:385
#3 0x00005555557ef000 in hists__findnew_entry (hists=0x555556039d60, entry=0x7fffffffa4c0, al=0x7fffffffa8c0, sample_self=true)
at util/hist.c:644
#4 0x00005555557ef61c in __hists__add_entry (hists=0x555556039d60, al=0x7fffffffa8c0, sym_parent=0x0, bi=0x0, mi=0x0, ki=0x0,
block_info=0x0, sample=0x7fffffffaa90, sample_self=true, ops=0x0) at util/hist.c:761
#5 0x00005555557ef71f in hists__add_entry (hists=0x555556039d60, al=0x7fffffffa8c0, sym_parent=0x0, bi=0x0, mi=0x0, ki=0x0,
sample=0x7fffffffaa90, sample_self=true) at util/hist.c:779
#6 0x00005555557f00fb in iter_add_single_normal_entry (iter=0x7fffffffa900, al=0x7fffffffa8c0) at util/hist.c:1015
#7 0x00005555557f09a7 in hist_entry_iter__add (iter=0x7fffffffa900, al=0x7fffffffa8c0, max_stack_depth=127, arg=0x7fffffffbce0)
at util/hist.c:1260
#8 0x00005555555ba7ce in process_sample_event (tool=0x7fffffffbce0, event=0x7ffff7c14128, sample=0x7fffffffaa90, evsel=0x555556039ad0,
machine=0x5555560388e8) at builtin-report.c:334
#9 0x00005555557b30c8 in evlist__deliver_sample (evlist=0x555556039010, tool=0x7fffffffbce0, event=0x7ffff7c14128,
sample=0x7fffffffaa90, evsel=0x555556039ad0, machine=0x5555560388e8) at util/session.c:1232
#10 0x00005555557b32bc in machines__deliver_event (machines=0x5555560388e8, evlist=0x555556039010, event=0x7ffff7c14128,
sample=0x7fffffffaa90, tool=0x7fffffffbce0, file_offset=110888, file_path=0x555556038ff0 "perf.data") at util/session.c:1271
#11 0x00005555557b3848 in perf_session__deliver_event (session=0x5555560386d0, event=0x7ffff7c14128, tool=0x7fffffffbce0,
file_offset=110888, file_path=0x555556038ff0 "perf.data") at util/session.c:1354
#12 0x00005555557affaf in ordered_events__deliver_event (oe=0x555556038e60, event=0x555556135aa0) at util/session.c:132
#13 0x00005555557bb605 in do_flush (oe=0x555556038e60, show_progress=false) at util/ordered-events.c:245
#14 0x00005555557bb95c in __ordered_events__flush (oe=0x555556038e60, how=OE_FLUSH__ROUND, timestamp=0) at util/ordered-events.c:324
#15 0x00005555557bba46 in ordered_events__flush (oe=0x555556038e60, how=OE_FLUSH__ROUND) at util/ordered-events.c:342
#16 0x00005555557b1b3b in perf_event__process_finished_round (tool=0x7fffffffbce0, event=0x7ffff7c15bb8, oe=0x555556038e60)
at util/session.c:780
#17 0x00005555557b3b27 in perf_session__process_user_event (session=0x5555560386d0, event=0x7ffff7c15bb8, file_offset=117688,
file_path=0x555556038ff0 "perf.data") at util/session.c:1406
As you can see the entry->ms.map was NULL even if he->ms.map has a
value. This is because 'sym' sort key is not given, so it cannot assume
whether he->ms.sym and entry->ms.sym is the same. I only checked the
'sym' sort key here as it implies 'dso' behavior (so maps are the same).
Fixes: ac01c8c4246546fd ("perf hist: Update hist symbol when updating maps")
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240826221045.1202305-2-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/util/hist.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -633,7 +633,7 @@ static struct hist_entry *hists__findnew
* mis-adjust symbol addresses when computing
* the history counter to increment.
*/
- if (he->ms.map != entry->ms.map) {
+ if (hists__has(hists, sym) && he->ms.map != entry->ms.map) {
if (he->ms.sym) {
u64 addr = he->ms.sym->start;
he->ms.sym = map__find_symbol(entry->ms.map, addr);
