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perf trace: Fix wrong size to bpf_map__update_elem call

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In linux-next
commit c760174401 ("perf cpumap: Reduce cpu size from int to int16_t")
causes the perf tests 100 126 to fail on s390:

Output before:
 # ./perf test 100
 100: perf trace BTF general tests         : FAILED!
 #

The root cause is the change from int to int16_t for the
cpu maps. The size of the CPU key value pair changes from
four bytes to two bytes. However a two byte key size is
not supported for bpf_map__update_elem().
Note: validate_map_op() in libbpf.c emits warning
 libbpf: map '__augmented_syscalls__': \
	 unexpected key size 2 provided, expected 4
when key size is set to int16_t.

Therefore change to variable size back to 4 bytes for
invocation of bpf_map__update_elem().

Output after:
 # ./perf test 100
 100: perf trace BTF general tests         : Ok
 #

Fixes: c760174401 ("perf cpumap: Reduce cpu size from int to int16_t")
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Acked-by: Howard Chu <howardchu95@gmail.com>
Cc: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250324152756.3879571-1-tmricht@linux.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
Thomas Richter
2025-03-24 16:27:56 +01:00
committed by Namhyung Kim
parent 9a352a90e8
commit 216d567610
1 changed files with 4 additions and 2 deletions
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6
tools/perf/builtin-trace.c
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@@ -4476,10 +4476,12 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
* CPU the bpf-output event's file descriptor.
*/
perf_cpu_map__for_each_cpu(cpu, i, trace->syscalls.events.bpf_output->core.cpus) {
int mycpu = cpu.cpu;
bpf_map__update_elem(trace->skel->maps.__augmented_syscalls__,
&cpu.cpu, sizeof(int),
&mycpu, sizeof(mycpu),
xyarray__entry(trace->syscalls.events.bpf_output->core.fd,
cpu.cpu, 0),
mycpu, 0),
sizeof(__u32), BPF_ANY);
}
}