[PATCH 1/1] Revert "perf record: Reduce memory for recording PERF_RECORD_LOST_SAMPLES event"

From: Arnaldo Carvalho de Melo
Date: Tue Jun 04 2024 - 10:00:22 EST


This reverts commit 7d1405c71df21f6c394b8a885aa8a133f749fa22.

This causes segfaults in some cases, as reported by Milian:

```
sudo /usr/bin/perf record -z --call-graph dwarf -e cycles -e
raw_syscalls:sys_enter ls
...
[ perf record: Woken up 3 times to write data ]
malloc(): invalid next size (unsorted)
Aborted
```

Backtrace with GDB + debuginfod:

```
malloc(): invalid next size (unsorted)

Thread 1 "perf" received signal SIGABRT, Aborted.
__pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6,
no_tid=no_tid@entry=0) at pthread_kill.c:44
Downloading source file /usr/src/debug/glibc/glibc/nptl/pthread_kill.c
44 return INTERNAL_SYSCALL_ERROR_P (ret) ? INTERNAL_SYSCALL_ERRNO
(ret) : 0;
(gdb) bt
#0 __pthread_kill_implementation (threadid=<optimized out>,
signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
#1 0x00007ffff6ea8eb3 in __pthread_kill_internal (threadid=<optimized out>,
signo=6) at pthread_kill.c:78
#2 0x00007ffff6e50a30 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/
raise.c:26
#3 0x00007ffff6e384c3 in __GI_abort () at abort.c:79
#4 0x00007ffff6e39354 in __libc_message_impl (fmt=fmt@entry=0x7ffff6fc22ea
"%s\n") at ../sysdeps/posix/libc_fatal.c:132
#5 0x00007ffff6eb3085 in malloc_printerr (str=str@entry=0x7ffff6fc5850
"malloc(): invalid next size (unsorted)") at malloc.c:5772
#6 0x00007ffff6eb657c in _int_malloc (av=av@entry=0x7ffff6ff6ac0
<main_arena>, bytes=bytes@entry=368) at malloc.c:4081
#7 0x00007ffff6eb877e in __libc_calloc (n=<optimized out>,
elem_size=<optimized out>) at malloc.c:3754
#8 0x000055555569bdb6 in perf_session.do_write_header ()
#9 0x00005555555a373a in __cmd_record.constprop.0 ()
#10 0x00005555555a6846 in cmd_record ()
#11 0x000055555564db7f in run_builtin ()
#12 0x000055555558ed77 in main ()
```

Valgrind memcheck:
```
==45136== Invalid write of size 8
==45136== at 0x2B38A5: perf_event__synthesize_id_sample (in /usr/bin/perf)
==45136== by 0x157069: __cmd_record.constprop.0 (in /usr/bin/perf)
==45136== by 0x15A845: cmd_record (in /usr/bin/perf)
==45136== by 0x201B7E: run_builtin (in /usr/bin/perf)
==45136== by 0x142D76: main (in /usr/bin/perf)
==45136== Address 0x6a866a8 is 0 bytes after a block of size 40 alloc'd
==45136== at 0x4849BF3: calloc (vg_replace_malloc.c:1675)
==45136== by 0x3574AB: zalloc (in /usr/bin/perf)
==45136== by 0x1570E0: __cmd_record.constprop.0 (in /usr/bin/perf)
==45136== by 0x15A845: cmd_record (in /usr/bin/perf)
==45136== by 0x201B7E: run_builtin (in /usr/bin/perf)
==45136== by 0x142D76: main (in /usr/bin/perf)
==45136==
==45136== Syscall param write(buf) points to unaddressable byte(s)
==45136== at 0x575953D: __libc_write (write.c:26)
==45136== by 0x575953D: write (write.c:24)
==45136== by 0x35761F: ion (in /usr/bin/perf)
==45136== by 0x357778: writen (in /usr/bin/perf)
==45136== by 0x1548F7: record__write (in /usr/bin/perf)
==45136== by 0x15708A: __cmd_record.constprop.0 (in /usr/bin/perf)
==45136== by 0x15A845: cmd_record (in /usr/bin/perf)
==45136== by 0x201B7E: run_builtin (in /usr/bin/perf)
==45136== by 0x142D76: main (in /usr/bin/perf)
==45136== Address 0x6a866a8 is 0 bytes after a block of size 40 alloc'd
==45136== at 0x4849BF3: calloc (vg_replace_malloc.c:1675)
==45136== by 0x3574AB: zalloc (in /usr/bin/perf)
==45136== by 0x1570E0: __cmd_record.constprop.0 (in /usr/bin/perf)
==45136== by 0x15A845: cmd_record (in /usr/bin/perf)
==45136== by 0x201B7E: run_builtin (in /usr/bin/perf)
==45136== by 0x142D76: main (in /usr/bin/perf)
==45136==
-----

Closes: https://lore.kernel.org/linux-perf-users/23879991.0LEYPuXRzz@milian-workstation/
Reported-by: Milian Wolff <milian.wolff@xxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: stable@xxxxxxxxxx # 6.8+
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-record.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 66a3de8ac66186b0..0a8ba1323d64be6b 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1956,8 +1956,7 @@ static void record__read_lost_samples(struct record *rec)

if (count.lost) {
if (!lost) {
- lost = zalloc(sizeof(*lost) +
- session->machines.host.id_hdr_size);
+ lost = zalloc(PERF_SAMPLE_MAX_SIZE);
if (!lost) {
pr_debug("Memory allocation failed\n");
return;
@@ -1973,8 +1972,7 @@ static void record__read_lost_samples(struct record *rec)
lost_count = perf_bpf_filter__lost_count(evsel);
if (lost_count) {
if (!lost) {
- lost = zalloc(sizeof(*lost) +
- session->machines.host.id_hdr_size);
+ lost = zalloc(PERF_SAMPLE_MAX_SIZE);
if (!lost) {
pr_debug("Memory allocation failed\n");
return;
--
2.45.1