Re: [Potential Spoof] [PATCH bpf-next 3/3] selftests/bpf: reset process and thread affinity after each test/sub-test
From: Martin KaFai Lau <hidden>
Date: 2020-03-17 05:36:10
Also in:
bpf
On Fri, Mar 13, 2020 at 06:39:32PM -0700, Andrii Nakryiko wrote:
quoted hunk ↗ jump to hunk
Some tests and sub-tests are setting "custom" thread/process affinity and don't reset it back. Instead of requiring each test to undo all this, ensure that thread affinity is restored by test_progs test runner itself. Signed-off-by: Andrii Nakryiko <redacted> --- tools/testing/selftests/bpf/test_progs.c | 42 +++++++++++++++++++++++- tools/testing/selftests/bpf/test_progs.h | 1 + 2 files changed, 42 insertions(+), 1 deletion(-)diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index c8cb407482c6..b521e0a512b6 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c@@ -1,12 +1,15 @@ // SPDX-License-Identifier: GPL-2.0-only /* Copyright (c) 2017 Facebook */ +#define _GNU_SOURCE #include "test_progs.h" #include "cgroup_helpers.h" #include "bpf_rlimit.h" #include <argp.h> -#include <string.h> +#include <pthread.h> +#include <sched.h> #include <signal.h> +#include <string.h> #include <execinfo.h> /* backtrace */ /* defined in test_progs.h */@@ -90,6 +93,34 @@ static void skip_account(void) } } +static void stdio_restore(void); + +/* A bunch of tests set custom affinity per-thread and/or per-process. Reset + * it after each test/sub-test. + */ +static void reset_affinity() { + + cpu_set_t cpuset; + int i, err; + + CPU_ZERO(&cpuset); + for (i = 0; i < env.nr_cpus; i++) + CPU_SET(i, &cpuset);
In case the user may run "taskset somemask test_progs", is it better to store the inital_cpuset at the beginning of main and then restore to inital_cpuset after each run?
+
+ err = sched_setaffinity(0, sizeof(cpuset), &cpuset);
+ if (err < 0) {
+ stdio_restore();
+ fprintf(stderr, "Failed to reset process affinity: %d!\n", err);
+ exit(-1);
+ }
+ err = pthread_setaffinity_np(pthread_self(), sizeof(cpuset), &cpuset);
+ if (err < 0) {
+ stdio_restore();
+ fprintf(stderr, "Failed to reset thread affinity: %d!\n", err);
+ exit(-1);
+ }
+}