[PATCH 1/2] perf record: Fix cpu mask bit setting for mixed mmaps

From: Adrian Hunter
Date: Thu Sep 15 2022 - 08:26:42 EST


With mixed per-thread and (system-wide) per-cpu maps, the "any cpu" value
-1 must be skipped when setting CPU mask bits.

Prior to commit cbd7bfc7fd99 ("tools/perf: Fix out of bound access to cpu
mask array") the invalid setting went unnoticed, but since then it causes
perf record to fail with an error.

Example:

Before:

$ perf record -e intel_pt// --per-thread uname
Failed to initialize parallel data streaming masks

After:

$ perf record -e intel_pt// --per-thread uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.068 MB perf.data ]

Fixes: ae4f8ae16a07 ("libperf evlist: Allow mixing per-thread and per-cpu mmaps")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/perf/builtin-record.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 5b808ac7a281..b76637ed2462 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -3535,6 +3535,8 @@ static int record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_cp
return 0;

perf_cpu_map__for_each_cpu(cpu, idx, cpus) {
+ if (cpu.cpu == -1)
+ continue;
/* Return ENODEV is input cpu is greater than max cpu */
if ((unsigned long)cpu.cpu > mask->nbits)
return -ENODEV;
--
2.25.1