Re: [PATCH 01/27] perf session: Add minimum event size and alignment validation

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Thu, May 21, 2026 at 01:59:19AM +0000, sashiko-bot@kernel.org wrote:
> Pre-existing issues:
> - [High] `perf_session__process_event` returns `event->header.size` for unknown event types, causing the stream reader to skip double the event size.

> >  
> >  	if (event->header.type >= PERF_RECORD_HEADER_MAX) {
> >  		/* This perf is outdated and does not support the latest event type. */
> >  		ui__warning("Unsupported header type %u, please consider updating perf.\n",
> >  			    event->header.type);
> > -		return -EINVAL;
> > -
> > +		/* Skip unsupported event by returning its size. */
> > +		return event->header.size;
> >  	}
 
> [Severity: High]
> This is a pre-existing issue, but does returning event->header.size for
> unknown event types cause the stream reader to skip too far?
 
> When the caller reader__read_event() initializes size = event->header.size
> and adds the positive return value (skip), it causes the reader to advance
> by 2 * event->header.size.
 
> Could this misalign the stream and break parsing for the rest of the file?

Will be addressed in v2.

- Arnaldo