Re: [PATCH v2 0/3] Support .gnu_debugdata for symbols in perf

[Namhyung Kim]

On Thu, Feb 20, 2025 at 10:55:08AM -0800, Stephen Brennan wrote:
> Hello all,
> 
> This series adds the ability to read symbols from the ".gnu_debugdata" section,
> an LZMA-compressed embedded ELF file which is supposed to contain additional ELF
> symbols. This is something that Fedora implemented (as "MiniDebuginfo" [1]).
> There are more details in v1. I've tested it with binaries that have
> .gnu_debugdata, and I've also ensured that the build & runtime work when LZMA is
> disabled.
> 
> [1]: https://fedoraproject.org/wiki/Features/MiniDebugInfo
> 
> Changes since v1:
> * Reuses the existing LZMA decompression helpers, rather than implementing a
>   new LZMA decompression loop. This does involve creating a temporary file, but
>   I think that actually makes things cleaner, since now the symsrc has a file
>   descriptor to close, rather than adding a new pointer that needs freeing.
> * I did also remove the pr_debug() for the case where there is no
>   ".gnu_debugdata" section. That's not really an error worth logging, that's
>   just normal operation.
> * I added a pr_debug() for the case where we successfully load .gnu_debugdata
>   so that it's easier to determine whether it gets used in tests.

Thanks, it'd be nice if anyone with a Fedora box could test this.

Thanks,
Namhyung

> 
> v1: https://lore.kernel.org/linux-perf-users/20250213190542.3249050-1-stephen.s.brennan@xxxxxxxxxx/
> 
> Stephen Brennan (3):
>   tools: perf: add dummy functions for !HAVE_LZMA_SUPPORT
>   tools: perf: add LZMA decompression from FILE
>   tools: perf: support .gnu_debugdata for symbols
> 
>  tools/perf/util/compress.h   |  20 +++++++
>  tools/perf/util/dso.c        |   2 +
>  tools/perf/util/dso.h        |   1 +
>  tools/perf/util/lzma.c       |  29 ++++++----
>  tools/perf/util/symbol-elf.c | 106 ++++++++++++++++++++++++++++++++++-
>  tools/perf/util/symbol.c     |   2 +
>  6 files changed, 147 insertions(+), 13 deletions(-)
> 
> -- 
> 2.43.5
>