This is a note to let you know that I've just added the patch titled
selftests/bpf: Fix massive output from test_maps
to the 4.19-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:
selftests-bpf-fix-massive-output-from-test_maps.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9475f1df000ed113eea210f2605ed6e0f3fa93b0
Author: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Date: Wed Aug 26 10:17:36 2020 +0200
selftests/bpf: Fix massive output from test_maps
[ Upstream commit fa4505675e093e895b7ec49a76d44f6b5ad9602e ]
When stdout output from the selftests tool 'test_maps' gets redirected
into e.g file or pipe, then the output lines increase a lot (from 21
to 33949 lines). This is caused by the printf that happens before the
fork() call, and there are user-space buffered printf data that seems
to be duplicated into the forked process.
To fix this fflush() stdout before the fork loop in __run_parallel().
Fixes: 1a97cf1fe503 ("selftests/bpf: speedup test_maps")
Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/bpf/159842985651.1050885.2154399297503372406.stgit@firesoul
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c
index 9b552c0fc47db..4e202217fae10 100644
--- a/tools/testing/selftests/bpf/test_maps.c
+++ b/tools/testing/selftests/bpf/test_maps.c
@@ -1017,6 +1017,8 @@ static void __run_parallel(int tasks, void (*fn)(int task, void *data),
pid_t pid[tasks];
int i;
+ fflush(stdout);
+
for (i = 0; i < tasks; i++) {
pid[i] = fork();
if (pid[i] == 0) {
