Re: [PATCH linux-5.15.y v2] perf machine: Use path__join() to compose a path instead of snprintf(dir, '/', filename)

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Sep 12, 2022 at 04:15:22PM +0800, Jisheng Zhang wrote:
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> commit 9d5f0c36438eeae7566ca383b2b673179e3cc613 upstream.
> 
> Its more intention revealing, and if we're interested in the odd cases
> where this may end up truncating we can do debug checks at one
> centralized place.
> 
> Motivation, of all the container builds, fedora rawhide started
> complaining of:
> 
>   util/machine.c: In function ‘machine__create_modules’:
>   util/machine.c:1419:50: error: ‘%s’ directive output may be truncated writing up to 255 bytes into a region of size between 0 and 4095 [-Werror=format-truncation=]
>    1419 |                 snprintf(path, sizeof(path), "%s/%s", dir_name, dent->d_name);
>         |                                                  ^~
>   In file included from /usr/include/stdio.h:894,
>                    from util/branch.h:9,
>                    from util/callchain.h:8,
>                    from util/machine.c:7:
>   In function ‘snprintf’,
>       inlined from ‘maps__set_modules_path_dir’ at util/machine.c:1419:3,
>       inlined from ‘machine__set_modules_path’ at util/machine.c:1473:9,
>       inlined from ‘machine__create_modules’ at util/machine.c:1519:7:
>   /usr/include/bits/stdio2.h:71:10: note: ‘__builtin___snprintf_chk’ output between 2 and 4352 bytes into a destination of size 4096
> 
> There are other places where we should use path__join(), but lets get rid of
> this one first.
> 
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Acked-by: Ian Rogers <irogers@google.com>
> Link: Link: https://lore.kernel.org/r/YebZKjwgfdOz0lAs@kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

As you are forwarding on this commit, you too need to sign-off on it.

> ---
> 
> Since v1:
>  - add commit id in upstream.
>  - add linux-5.15.y, maybe we also need this for other long term stable
>    tree.

Why is this needed in 5.15?

thanks,

greg k-h