Patch "perf bench internals inject-build-id: Fix trap divide when collecting just one DSO" has been added to the 6.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    perf bench internals inject-build-id: Fix trap divide when collecting just one DSO

to the 6.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-bench-internals-inject-build-id-fix-trap-divide.patch
and it can be found in the queue-6.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d81b5448e36ba02ea45c1817b465039039fbf71a
Author: He Zhe <zhe.he@xxxxxxxxxxxxx>
Date:   Tue May 7 14:50:26 2024 +0800

    perf bench internals inject-build-id: Fix trap divide when collecting just one DSO
    
    [ Upstream commit d9180e23fbfa3875424d3a6b28b71b072862a52a ]
    
    'perf bench internals inject-build-id' suffers from the following error when
    only one DSO is collected.
    
      # perf bench internals inject-build-id -v
        Collected 1 DSOs
      traps: internals-injec[2305] trap divide error
      ip:557566ba6394 sp:7ffd4de97fe0 error:0 in perf[557566b2a000+23d000]
        Build-id injection benchmark
        Iteration #1
      Floating point exception
    
    This patch removes the unnecessary minus one from the divisor which also
    corrects the randomization range.
    
    Signed-off-by: He Zhe <zhe.he@xxxxxxxxxxxxx>
    Fixes: 0bf02a0d80427f26 ("perf bench: Add build-id injection benchmark")
    Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
    Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
    Cc: Ian Rogers <irogers@xxxxxxxxxx>
    Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
    Cc: Mark Rutland <mark.rutland@xxxxxxx>
    Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240507065026.2652929-1-zhe.he@xxxxxxxxxxxxx
    Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/perf/bench/inject-buildid.c b/tools/perf/bench/inject-buildid.c
index 49331743c7439..a759eb2328bea 100644
--- a/tools/perf/bench/inject-buildid.c
+++ b/tools/perf/bench/inject-buildid.c
@@ -362,7 +362,7 @@ static int inject_build_id(struct bench_data *data, u64 *max_rss)
 		return -1;
 
 	for (i = 0; i < nr_mmaps; i++) {
-		int idx = rand() % (nr_dsos - 1);
+		int idx = rand() % nr_dsos;
 		struct bench_dso *dso = &dsos[idx];
 		u64 timestamp = rand() % 1000000;