Re: [PATCH v1 0/3] perf probe: Support long symbol

[Google]

On Wed, 9 Oct 2024 18:12:52 -0700
Namhyung Kim <namhyung@xxxxxxxxxx> wrote:

> Hello Leo,
> 
> On Mon, Oct 07, 2024 at 03:11:13PM +0100, Leo Yan wrote:
> > Currently, a probe supports event name maximum to a 64-byte length. The
> > event name comes from the probed symbol name, otherwise, user can
> > specify an event name.
> > 
> > In the case when user tries to inject a probe for a long symbol, e.g.
> > mangled symbol name in a C++ program, the kernel buffer cannot
> > accommodate it if the symbol name is longer than 64 bytes.
> > 
> > On the other hand, this series relies on the perf tool to resolve the
> > issue. When the tool detects user doesn't specify event name and the
> > probed symbol is longer than 64 bytes, it will generate a hashed event
> > name with 64-byte length to avoid failure.
> 
> Please CC Masami for probe related changes in the future.

Thanks Namhyung,

Let me find the patches.

> 
> Thanks,
> Namhyung
> 
> > 
> > 
> > Leo Yan (3):
> >   perf: Dynamically allocate buffer for event string
> >   perf probe: Check group string length
> >   perf probe: Generate hash event for long symbol
> > 
> >  tools/perf/util/probe-event.c | 71 ++++++++++++++++++++++++++++++++---
> >  1 file changed, 65 insertions(+), 6 deletions(-)
> > 
> > -- 
> > 2.34.1
> > 


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>