* [PATCH bpf-next v2 1/2] libbpf: Extend BPF_KSYSCALL documentation
2022-07-26 13:40 [PATCH bpf-next v2 0/2] Fix test_probe_user on s390x Ilya Leoshkevich
@ 2022-07-26 13:40 ` Ilya Leoshkevich
2022-07-26 13:40 ` [PATCH bpf-next v2 2/2] selftests/bpf: Attach to socketcall() in test_probe_user Ilya Leoshkevich
2022-07-26 14:14 ` [PATCH bpf-next v2 0/2] Fix test_probe_user on s390x Jiri Olsa
2 siblings, 0 replies; 5+ messages in thread
From: Ilya Leoshkevich @ 2022-07-26 13:40 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
Cc: bpf, Heiko Carstens, Vasily Gorbik, Jiri Olsa, Ilya Leoshkevich
Explicitly list known quirks.
Mention that socket-related syscalls can be invoked via socketcall().
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
tools/lib/bpf/bpf_tracing.h | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index f4d3e1e2abe2..43ca3aff2292 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -523,10 +523,17 @@ static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args)
* Original struct pt_regs * context is preserved as 'ctx' argument. This might
* be necessary when using BPF helpers like bpf_perf_event_output().
*
- * At the moment BPF_KSYSCALL does not handle all the calling convention
- * quirks for mmap(), clone() and compat syscalls transparrently. This may or
- * may not change in the future. User needs to take extra measures to handle
- * such quirks explicitly, if necessary.
+ * At the moment BPF_KSYSCALL does not transparently handle all the calling
+ * convention quirks for the following syscalls:
+ *
+ * - mmap(): __ARCH_WANT_SYS_OLD_MMAP.
+ * - clone(): CONFIG_CLONE_BACKWARDS, CONFIG_CLONE_BACKWARDS2 and
+ * CONFIG_CLONE_BACKWARDS3.
+ * - socket-related syscalls: __ARCH_WANT_SYS_SOCKETCALL.
+ * - compat syscalls.
+ *
+ * This may or may not change in the future. User needs to take extra measures
+ * to handle such quirks explicitly, if necessary.
*
* This macro relies on BPF CO-RE support and virtual __kconfig externs.
*/
--
2.35.3
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH bpf-next v2 2/2] selftests/bpf: Attach to socketcall() in test_probe_user
2022-07-26 13:40 [PATCH bpf-next v2 0/2] Fix test_probe_user on s390x Ilya Leoshkevich
2022-07-26 13:40 ` [PATCH bpf-next v2 1/2] libbpf: Extend BPF_KSYSCALL documentation Ilya Leoshkevich
@ 2022-07-26 13:40 ` Ilya Leoshkevich
2022-07-26 14:14 ` [PATCH bpf-next v2 0/2] Fix test_probe_user on s390x Jiri Olsa
2 siblings, 0 replies; 5+ messages in thread
From: Ilya Leoshkevich @ 2022-07-26 13:40 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
Cc: bpf, Heiko Carstens, Vasily Gorbik, Jiri Olsa, Ilya Leoshkevich
test_probe_user fails on architectures where libc uses
socketcall(SYS_CONNECT) instead of connect(). Fix by attaching to
socketcall as well.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
.../selftests/bpf/prog_tests/probe_user.c | 35 +++++++++++++------
.../selftests/bpf/progs/test_probe_user.c | 32 +++++++++++++++--
2 files changed, 54 insertions(+), 13 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/probe_user.c b/tools/testing/selftests/bpf/prog_tests/probe_user.c
index abf890d066eb..34dbd2adc157 100644
--- a/tools/testing/selftests/bpf/prog_tests/probe_user.c
+++ b/tools/testing/selftests/bpf/prog_tests/probe_user.c
@@ -4,25 +4,35 @@
/* TODO: corrupts other tests uses connect() */
void serial_test_probe_user(void)
{
- const char *prog_name = "handle_sys_connect";
+ static const char *const prog_names[] = {
+ "handle_sys_connect",
+#if defined(__s390x__)
+ "handle_sys_socketcall",
+#endif
+ };
+ enum { prog_count = ARRAY_SIZE(prog_names) };
const char *obj_file = "./test_probe_user.o";
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, );
int err, results_map_fd, sock_fd, duration = 0;
struct sockaddr curr, orig, tmp;
struct sockaddr_in *in = (struct sockaddr_in *)&curr;
- struct bpf_link *kprobe_link = NULL;
- struct bpf_program *kprobe_prog;
+ struct bpf_link *kprobe_links[prog_count] = {};
+ struct bpf_program *kprobe_progs[prog_count];
struct bpf_object *obj;
static const int zero = 0;
+ size_t i;
obj = bpf_object__open_file(obj_file, &opts);
if (!ASSERT_OK_PTR(obj, "obj_open_file"))
return;
- kprobe_prog = bpf_object__find_program_by_name(obj, prog_name);
- if (CHECK(!kprobe_prog, "find_probe",
- "prog '%s' not found\n", prog_name))
- goto cleanup;
+ for (i = 0; i < prog_count; i++) {
+ kprobe_progs[i] =
+ bpf_object__find_program_by_name(obj, prog_names[i]);
+ if (CHECK(!kprobe_progs[i], "find_probe",
+ "prog '%s' not found\n", prog_names[i]))
+ goto cleanup;
+ }
err = bpf_object__load(obj);
if (CHECK(err, "obj_load", "err %d\n", err))
@@ -33,9 +43,11 @@ void serial_test_probe_user(void)
"err %d\n", results_map_fd))
goto cleanup;
- kprobe_link = bpf_program__attach(kprobe_prog);
- if (!ASSERT_OK_PTR(kprobe_link, "attach_kprobe"))
- goto cleanup;
+ for (i = 0; i < prog_count; i++) {
+ kprobe_links[i] = bpf_program__attach(kprobe_progs[i]);
+ if (!ASSERT_OK_PTR(kprobe_links[i], "attach_kprobe"))
+ goto cleanup;
+ }
memset(&curr, 0, sizeof(curr));
in->sin_family = AF_INET;
@@ -69,6 +81,7 @@ void serial_test_probe_user(void)
inet_ntoa(in->sin_addr), ntohs(in->sin_port)))
goto cleanup;
cleanup:
- bpf_link__destroy(kprobe_link);
+ for (i = 0; i < prog_count; i++)
+ bpf_link__destroy(kprobe_links[i]);
bpf_object__close(obj);
}
diff --git a/tools/testing/selftests/bpf/progs/test_probe_user.c b/tools/testing/selftests/bpf/progs/test_probe_user.c
index 8e1495008e4d..476e310f8a0a 100644
--- a/tools/testing/selftests/bpf/progs/test_probe_user.c
+++ b/tools/testing/selftests/bpf/progs/test_probe_user.c
@@ -7,8 +7,7 @@
static struct sockaddr_in old;
-SEC("ksyscall/connect")
-int BPF_KSYSCALL(handle_sys_connect, int fd, struct sockaddr_in *uservaddr, int addrlen)
+static int handle_sys_connect_common(struct sockaddr_in *uservaddr)
{
struct sockaddr_in new;
@@ -19,4 +18,33 @@ int BPF_KSYSCALL(handle_sys_connect, int fd, struct sockaddr_in *uservaddr, int
return 0;
}
+SEC("ksyscall/connect")
+int BPF_KSYSCALL(handle_sys_connect, int fd, struct sockaddr_in *uservaddr,
+ int addrlen)
+{
+ return handle_sys_connect_common(uservaddr);
+}
+
+#if defined(bpf_target_s390)
+
+#ifndef SYS_CONNECT
+#define SYS_CONNECT 3
+#endif
+
+SEC("ksyscall/socketcall")
+int BPF_KSYSCALL(handle_sys_socketcall, int call, unsigned long *args)
+{
+ if (call == SYS_CONNECT) {
+ struct sockaddr_in *uservaddr;
+
+ bpf_probe_read_user(&uservaddr, sizeof(uservaddr), &args[1]);
+
+ return handle_sys_connect_common(uservaddr);
+ }
+
+ return 0;
+}
+
+#endif
+
char _license[] SEC("license") = "GPL";
--
2.35.3
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH bpf-next v2 0/2] Fix test_probe_user on s390x
2022-07-26 13:40 [PATCH bpf-next v2 0/2] Fix test_probe_user on s390x Ilya Leoshkevich
2022-07-26 13:40 ` [PATCH bpf-next v2 1/2] libbpf: Extend BPF_KSYSCALL documentation Ilya Leoshkevich
2022-07-26 13:40 ` [PATCH bpf-next v2 2/2] selftests/bpf: Attach to socketcall() in test_probe_user Ilya Leoshkevich
@ 2022-07-26 14:14 ` Jiri Olsa
2022-07-26 14:37 ` Daniel Borkmann
2 siblings, 1 reply; 5+ messages in thread
From: Jiri Olsa @ 2022-07-26 14:14 UTC (permalink / raw)
To: Ilya Leoshkevich
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, bpf,
Heiko Carstens, Vasily Gorbik
On Tue, Jul 26, 2022 at 03:40:06PM +0200, Ilya Leoshkevich wrote:
> Hi,
>
> This is a fix for [1]: test_probe_user fails on s390x, because it hooks
> only connect(), but not socketcall(SYS_CONNECT).
>
> Patch 1 adds this quirk to BPF_KSYSCALL documentation.
> Patch 2 fixes the test by attaching a prog to socketcall().
>
> Best regards,
> Ilya
>
> [1] https://lore.kernel.org/bpf/06631b122b9bd6258139a36b971bba3e79543503.camel@linux.ibm.com/
>
> v1: https://lore.kernel.org/bpf/20220723020344.21699-1-iii@linux.ibm.com/
> v1 -> v2: Add CONFIG_ prefix to CLONE_BACKWARDS* symbols (Jiri).
> Change the type of prog_names to make checkpatch happy.
> Use prog_count everywhere (Jiri).
> #ifdef out handle_sys_socketcall() on non-s390x (Jiri).
LGTM
Acked-by: Jiri Olsa <jolsa@kernel.org>
thanks,
jirka
>
> Ilya Leoshkevich (2):
> libbpf: Extend BPF_KSYSCALL documentation
> selftests/bpf: Attach to socketcall() in test_probe_user
>
> tools/lib/bpf/bpf_tracing.h | 15 +++++---
> .../selftests/bpf/prog_tests/probe_user.c | 35 +++++++++++++------
> .../selftests/bpf/progs/test_probe_user.c | 32 +++++++++++++++--
> 3 files changed, 65 insertions(+), 17 deletions(-)
>
> --
> 2.35.3
>
^ permalink raw reply [flat|nested] 5+ messages in thread