Re: [PATCH 5/5] perf dso: Replace assert with runtime check in dso__read_symbol()

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

On Thu, Aug 13, 2026 at 03:26:29PM +0000, sashiko-bot@kernel.org wrote:
> > +++ b/tools/perf/util/dso.c
> > @@ -2038,7 +2038,12 @@ const u8 *dso__read_symbol(struct dso *dso, const char *symfs_filename,
> >  			errno = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
> >  			return NULL;
> >  		}
> > -		assert(len <= info_linear->info.jited_prog_len);
> > +		if (len > info_linear->info.jited_prog_len) {
> > +			pr_debug("BPF symbol length %zu exceeds jited_prog_len %u\n",
> > +				 len, info_linear->info.jited_prog_len);
> > +			errno = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
 
> [Severity: Medium]
> Since this is a bounds check failure in dso__read_symbol() triggered by a
> corrupted perf.data file, reusing SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF might
> cause tools to incorrectly report that the BPF file is missing its BTF section
> instead of indicating a length mismatch.
 
> Could this regression result in a confusing message for the user?

Some other cases near here are returning this error as well, we need to
add more errors and update the associated symbol__strerror_disassemble
to print the more precise error messages, probably
SYMBOL_ANNOTATE_ERRNO__BPF_INVALID_BTF.

I will add this to a TODO file for a new patch series improving this
situation.

- Arnaldo