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libperf evlist: Avoid out-of-bounds access
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[ Upstream commit 1947b92464c3268381604bbe2ac977a3fd78192f ]

Parallel testing appears to show a race between allocating and setting
evsel ids. As there is a bounds check on the xyarray it yields a segv
like:

```
AddressSanitizer:DEADLYSIGNAL

=================================================================

==484408==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000010

==484408==The signal is caused by a WRITE memory access.

==484408==Hint: address points to the zero page.

    #0 0x55cef5d4eff4 in perf_evlist__id_hash tools/lib/perf/evlist.c:256
    compulab-yokneam#1 0x55cef5d4f132 in perf_evlist__id_add tools/lib/perf/evlist.c:274
    compulab-yokneam#2 0x55cef5d4f545 in perf_evlist__id_add_fd tools/lib/perf/evlist.c:315
    compulab-yokneam#3 0x55cef5a1923f in store_evsel_ids util/evsel.c:3130
    compulab-yokneam#4 0x55cef5a19400 in evsel__store_ids util/evsel.c:3147
    compulab-yokneam#5 0x55cef5888204 in __run_perf_stat tools/perf/builtin-stat.c:832
    compulab-yokneam#6 0x55cef5888c06 in run_perf_stat tools/perf/builtin-stat.c:960
    compulab-yokneam#7 0x55cef58932db in cmd_stat tools/perf/builtin-stat.c:2878
...
```

Avoid this crash by early exiting the perf_evlist__id_add_fd and
perf_evlist__id_add is the access is out-of-bounds.

Signed-off-by: Ian Rogers <[email protected]>
Cc: Yang Jihong <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
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captain5050 authored and gregkh committed Apr 13, 2024
1 parent 5dcded2 commit be113e0
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Showing 2 changed files with 14 additions and 8 deletions.
18 changes: 12 additions & 6 deletions tools/lib/perf/evlist.c
Original file line number Diff line number Diff line change
Expand Up @@ -224,10 +224,10 @@ u64 perf_evlist__read_format(struct perf_evlist *evlist)

static void perf_evlist__id_hash(struct perf_evlist *evlist,
struct perf_evsel *evsel,
int cpu, int thread, u64 id)
int cpu_map_idx, int thread, u64 id)
{
int hash;
struct perf_sample_id *sid = SID(evsel, cpu, thread);
struct perf_sample_id *sid = SID(evsel, cpu_map_idx, thread);

sid->id = id;
sid->evsel = evsel;
Expand All @@ -245,21 +245,27 @@ void perf_evlist__reset_id_hash(struct perf_evlist *evlist)

void perf_evlist__id_add(struct perf_evlist *evlist,
struct perf_evsel *evsel,
int cpu, int thread, u64 id)
int cpu_map_idx, int thread, u64 id)
{
perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
if (!SID(evsel, cpu_map_idx, thread))
return;

perf_evlist__id_hash(evlist, evsel, cpu_map_idx, thread, id);
evsel->id[evsel->ids++] = id;
}

int perf_evlist__id_add_fd(struct perf_evlist *evlist,
struct perf_evsel *evsel,
int cpu, int thread, int fd)
int cpu_map_idx, int thread, int fd)
{
u64 read_data[4] = { 0, };
int id_idx = 1; /* The first entry is the counter value */
u64 id;
int ret;

if (!SID(evsel, cpu_map_idx, thread))
return -1;

ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
if (!ret)
goto add;
Expand Down Expand Up @@ -288,7 +294,7 @@ int perf_evlist__id_add_fd(struct perf_evlist *evlist,
id = read_data[id_idx];

add:
perf_evlist__id_add(evlist, evsel, cpu, thread, id);
perf_evlist__id_add(evlist, evsel, cpu_map_idx, thread, id);
return 0;
}

Expand Down
4 changes: 2 additions & 2 deletions tools/lib/perf/include/internal/evlist.h
Original file line number Diff line number Diff line change
Expand Up @@ -119,11 +119,11 @@ u64 perf_evlist__read_format(struct perf_evlist *evlist);

void perf_evlist__id_add(struct perf_evlist *evlist,
struct perf_evsel *evsel,
int cpu, int thread, u64 id);
int cpu_map_idx, int thread, u64 id);

int perf_evlist__id_add_fd(struct perf_evlist *evlist,
struct perf_evsel *evsel,
int cpu, int thread, int fd);
int cpu_map_idx, int thread, int fd);

void perf_evlist__reset_id_hash(struct perf_evlist *evlist);

Expand Down

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