On Tue, Feb 14, 2023 at 3:12 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote:
>
> eBPF selftests produce a few false positives with MSan. 3 of them have
> to do with sending uninitalized data via a socket. Another one is
> PERF_EVENT_IOC_QUERY_BPF, which is not known to MSan. Silence all of
> them using libbpf_mark_mem_written().
>
> Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
> ---
> tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c | 3 +++
> tools/testing/selftests/bpf/prog_tests/send_signal.c | 2 ++
> tools/testing/selftests/bpf/prog_tests/tp_attach_query.c | 4 ++++
> tools/testing/selftests/bpf/prog_tests/xdp_bonding.c | 3 +++
> 4 files changed, 12 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> index e980188d4124..c75a3357cd06 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> @@ -4,6 +4,7 @@
> #include <linux/err.h>
> #include <netinet/tcp.h>
> #include <test_progs.h>
> +#include <bpf/libbpf_internal.h>
> #include "network_helpers.h"
> #include "bpf_dctcp.skel.h"
> #include "bpf_cubic.skel.h"
> @@ -39,6 +40,8 @@ static void *server(void *arg)
> ssize_t nr_sent = 0, bytes = 0;
> char batch[1500];
>
> + libbpf_mark_mem_written(batch, sizeof(batch));
> +
> fd = accept(lfd, NULL, NULL);
> while (fd == -1) {
> if (errno == EINTR)
> diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c
> index d63a20fbed33..11e91fc7a67f 100644
> --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c
> +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c
> @@ -1,5 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0
> #include <test_progs.h>
> +#include <bpf/libbpf_internal.h>
> #include <sys/time.h>
> #include <sys/resource.h>
> #include "test_send_signal_kern.skel.h"
> @@ -58,6 +59,7 @@ static void test_send_signal_common(struct perf_event_attr *attr,
> ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority");
>
> /* notify parent signal handler is installed */
> + libbpf_mark_mem_written(buf, 1);
> ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write");
>
> /* make sure parent enabled bpf program to send_signal */
> diff --git a/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c b/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c
> index 770fcc3bb1ba..727898e905fe 100644
> --- a/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c
> +++ b/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c
> @@ -1,5 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0
> #include <test_progs.h>
> +#include <bpf/libbpf_internal.h>
libbpf doesn't install this header system-wide, so we should use ""
syntax, like all the other places in selftests do
>
> void serial_test_tp_attach_query(void)
> {
> @@ -66,6 +67,7 @@ void serial_test_tp_attach_query(void)
> if (i == 0) {
> /* check NULL prog array query */
> query->ids_len = num_progs;
> + libbpf_mark_var_written(query->prog_cnt);
> err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, query);
> if (CHECK(err || query->prog_cnt != 0,
> "perf_event_ioc_query_bpf",
> @@ -115,6 +117,8 @@ void serial_test_tp_attach_query(void)
> "err %d errno %d query->prog_cnt %u\n",
> err, errno, query->prog_cnt))
> goto cleanup3;
> + libbpf_mark_mem_written(query->ids,
> + query->ids_len * sizeof(__u32));
> for (j = 0; j < i + 1; j++)
> if (CHECK(saved_prog_ids[j] != query->ids[j],
> "perf_event_ioc_query_bpf",
> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c b/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c
> index 5e3a26b15ec6..e6334f254675 100644
> --- a/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c
> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c
> @@ -14,6 +14,7 @@
> #include <net/if.h>
> #include <linux/if_link.h>
> #include "test_progs.h"
> +#include "bpf/libbpf_internal.h"
> #include "network_helpers.h"
> #include <linux/if_bonding.h>
> #include <linux/limits.h>
> @@ -224,6 +225,8 @@ static int send_udp_packets(int vary_dst_ip)
> int i, s = -1;
> int ifindex;
>
> + libbpf_mark_mem_written(buf, sizeof(buf));
> +
> s = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
> if (!ASSERT_GE(s, 0, "socket"))
> goto err;
> --
> 2.39.1
>
