perf build-id: Fix caching files with a wrong build ID
authorAdrian Hunter <adrian.hunter@intel.com>
Tue, 21 Jun 2022 12:51:44 +0000 (15:51 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 29 Jun 2022 07:03:31 +0000 (09:03 +0200)
commita8bbb4c26460cf5b6cda080c58c49faf10e9bcda
treeeaac7322a2f2a741cc3cafe8f3cbed1411bd5de2
parent46a78d1413350571eeffc5a8b2ff1eceeb9e305b
perf build-id: Fix caching files with a wrong build ID

commit ab66fdace8581ef3b4e7cf5381a168ed4058d779 upstream.

Build ID events associate a file name with a build ID.  However, when
using perf inject, there is no guarantee that the file on the current
machine at the current time has that build ID. Fix by comparing the
build IDs and skip adding to the cache if they are different.

Example:

  $ echo "int main() {return 0;}" > prog.c
  $ gcc -o prog prog.c
  $ perf record --buildid-all ./prog
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.019 MB perf.data ]
  $ file-buildid() { file $1 | awk -F= '{print $2}' | awk -F, '{print $1}' ; }
  $ file-buildid prog
  444ad9be165d8058a48ce2ffb4e9f55854a3293e
  $ file-buildid ~/.debug/$(pwd)/prog/444ad9be165d8058a48ce2ffb4e9f55854a3293e/elf
  444ad9be165d8058a48ce2ffb4e9f55854a3293e
  $ echo "int main() {return 1;}" > prog.c
  $ gcc -o prog prog.c
  $ file-buildid prog
  885524d5aaa24008a3e2b06caa3ea95d013c0fc5

Before:

  $ perf buildid-cache --purge $(pwd)/prog
  $ perf inject -i perf.data -o junk
  $ file-buildid ~/.debug/$(pwd)/prog/444ad9be165d8058a48ce2ffb4e9f55854a3293e/elf
  885524d5aaa24008a3e2b06caa3ea95d013c0fc5
  $

After:

  $ perf buildid-cache --purge $(pwd)/prog
  $ perf inject -i perf.data -o junk
  $ file-buildid ~/.debug/$(pwd)/prog/444ad9be165d8058a48ce2ffb4e9f55854a3293e/elf

  $

Fixes: 454c407ec17a0c63 ("perf: add perf-inject builtin")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Link: https://lore.kernel.org/r/20220621125144.5623-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tools/perf/util/build-id.c