2022-11-25 12:02:12

by Vincent Whitchurch

Subject: [PATCH] perf annotate: Work with vmlinux outside symfs

It is currently possible to use --symfs along with a vmlinux which lies
outside of the symfs by passing an absolute path to --vmlinux, thanks to
the check in dso__load_vmlinux() which handles this explicitly.

However, the annotate code lacks this check and thus perf annotate does
not work ("Internal error: Invalid -1 error code") for kernel functions
with this combination. Add the missing handling.

Signed-off-by: Vincent Whitchurch <[email protected]>
---
tools/perf/util/annotate.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index db475e44f42f..52bdec764545 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1695,7 +1695,11 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
* cache, or is just a kallsyms file, well, lets hope that this
* DSO is the same as when 'perf record' ran.
*/
- __symbol__join_symfs(filename, filename_size, dso->long_name);
+ if (dso->kernel && dso->long_name[0] == '/')
+ snprintf(filename, filename_size,
+ "%s", dso->long_name);
+ else
+ __symbol__join_symfs(filename, filename_size, dso->long_name);

mutex_lock(&dso->lock);
if (access(filename, R_OK) && errno == ENOENT && dso->nsinfo) {
--
2.34.1

2023-06-16 11:37:22

by Vincent Whitchurch

Subject: Re: [PATCH] perf annotate: Work with vmlinux outside symfs

On Fri, 2022-11-25 at 12:42 +0100, Vincent Whitchurch wrote:
> It is currently possible to use --symfs along with a vmlinux which lies
> outside of the symfs by passing an absolute path to --vmlinux, thanks to
> the check in dso__load_vmlinux() which handles this explicitly.
>
> However, the annotate code lacks this check and thus perf annotate does
> not work ("Internal error: Invalid -1 error code") for kernel functions
> with this combination. Add the missing handling.
>
> Signed-off-by: Vincent Whitchurch <[email protected]>

This patch was not merged and I did not receive any comments on it
either. Should I resend it? It still applies cleanly to current
mainline. Thanks.

2023-06-16 13:18:15

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH] perf annotate: Work with vmlinux outside symfs

Em Fri, Jun 16, 2023 at 10:21:52AM +0000, Vincent Whitchurch escreveu:
> On Fri, 2022-11-25 at 12:42 +0100, Vincent Whitchurch wrote:
> > It is currently possible to use --symfs along with a vmlinux which lies
> > outside of the symfs by passing an absolute path to --vmlinux, thanks to
> > the check in dso__load_vmlinux() which handles this explicitly.
> >
> > However, the annotate code lacks this check and thus perf annotate does
> > not work ("Internal error: Invalid -1 error code") for kernel functions
> > with this combination. Add the missing handling.
> >
> > Signed-off-by: Vincent Whitchurch <[email protected]>
>
> This patch was not merged and I did not receive any comments on it
> either. Should I resend it? It still applies cleanly to current
> mainline. Thanks.

Thanks for the ping, I checked dso__load_vmlinux() and it has:

if (vmlinux[0] == '/')
snprintf(symfs_vmlinux, sizeof(symfs_vmlinux), "%s", vmlinux);
else
symbol__join_symfs(symfs_vmlinux, vmlinux)

Exactly as you pointed out, applied.

- Arnaldo