Re: [PATCH v2 1/3] perf record: Fix multiple PERF_RECORD_COMPRESSED2 records per push

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Missing explicit `#include <string.h>` for `memset` in `builtin-record.c`.
--

commit cb8ac7d313a36a42601f85ffc5fb9a9061002bc0
Author: Dmitry Ilvokhin <d@ilvokhin.com>

perf record: Fix multiple PERF_RECORD_COMPRESSED2 records per push

This commit frames compressed records individually when produced rather
than rewriting a single header for an entire blob. This prevents truncation
of the header.size field when a compressed blob exceeds 64KB.

> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 4a5eba498c025..2562c3177eae1 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c

[ ... ]

> @@ -1590,18 +1577,29 @@ static void record__adjust_affinity(struct record *rec, struct mmap *map)
>  	}
>  }
>  
> -static size_t process_comp_header(void *record, size_t increment)
> +/*
> + * Called once with data_size == 0 to start a record, then once with
> + * data_size == compressed payload size to finalize and 8-byte-pad it
> + * (unaligned records trip ASan in the reader).
> + */
> +static size_t process_comp_header(void *record, size_t data_size)
>  {
>  	struct perf_record_compressed2 *event = record;
>  	size_t size = sizeof(*event);
>  
> -	if (increment) {
> -		event->header.size += increment;
> -		return increment;
> +	if (data_size) {
> +		size_t padding;
> +
> +		event->data_size = data_size;
> +		event->header.size = PERF_ALIGN(size + data_size, sizeof(u64));
> +		padding = event->header.size - size - data_size;
> +		memset(record + size + data_size, 0, padding);

[Severity: Low]
Does this file need an explicit include for <string.h>?

Relying on implicit header inclusion for POSIX libc functions like memset can
cause build failures on systems using musl libc, where implicit header graphs
differ from glibc.

> +		return data_size + padding;
>  	}
>  
>  	event->header.type = PERF_RECORD_COMPRESSED2;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1782743187.git.d@ilvokhin.com?part=1