Adding reattach tests for uprobe syscall tests to make sure
we can re-attach and optimize same uprobe multiple times.

The reason is that optimized uprobe does not restore original
nop10 after detach, but instead it uses 'jmp 8' instruction.

Making sure we can still install and optimize uprobe on top
of the 'jmp 8' instruction.

Signed-off-by: Jiri Olsa <[email protected]>
---
 .../selftests/bpf/prog_tests/uprobe_syscall.c | 115 ++++++++++++++++--
 1 file changed, 105 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c 
b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index c2e9e549c737..82b3c0ce9253 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
@@ -431,21 +431,27 @@ static void *check_attach(struct uprobe_syscall_executed 
*skel, trigger_t trigge
        return tramp;
 }
 
-static void check_detach(void *addr, void *tramp)
+static bool check_detach(void *addr, void *tramp)
 {
+       bool ok = true;
+
        /* [uprobes_trampoline] stays after detach */
-       ASSERT_OK(find_uprobes_trampoline(tramp), "uprobes_trampoline");
-       ASSERT_OK(memcmp(addr, jmp2B, 2), "jmp2B");
+       if (!ASSERT_OK(find_uprobes_trampoline(tramp), "uprobes_trampoline"))
+               ok = false;
+       if (!ASSERT_OK(memcmp(addr, jmp2B, 2), "jmp2B"))
+               ok = false;
+       return ok;
 }
 
-static void check(struct uprobe_syscall_executed *skel, struct bpf_link *link,
-                 trigger_t trigger, void *addr, int executed)
+static void *check(struct uprobe_syscall_executed *skel, struct bpf_link *link,
+                  trigger_t trigger, void *addr, int executed)
 {
        void *tramp;
 
        tramp = check_attach(skel, trigger, addr, executed);
        bpf_link__destroy(link);
        check_detach(addr, tramp);
+       return tramp;
 }
 
 static void test_uprobe_legacy(void)
@@ -456,6 +462,7 @@ static void test_uprobe_legacy(void)
        );
        struct bpf_link *link;
        unsigned long offset;
+       void *tramp;
 
        offset = get_uprobe_offset(&uprobe_test);
        if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
@@ -473,7 +480,28 @@ static void test_uprobe_legacy(void)
        if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts"))
                goto cleanup;
 
-       check(skel, link, uprobe_test, uprobe_test, 2);
+       tramp = check(skel, link, uprobe_test, uprobe_test, 2);
+
+       /* reattach and detach without triggering optimization */
+       link = bpf_program__attach_uprobe_opts(skel->progs.test_uprobe,
+                                              0, "/proc/self/exe", offset, 
NULL);
+       if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts"))
+               goto cleanup;
+
+       bpf_link__destroy(link);
+       if (!check_detach(uprobe_test, tramp))
+               goto cleanup;
+
+       uprobe_test();
+       ASSERT_EQ(skel->bss->executed, 2, "executed_no_probe");
+
+       /* reattach with triggering optimization */
+       link = bpf_program__attach_uprobe_opts(skel->progs.test_uprobe,
+                               0, "/proc/self/exe", offset, NULL);
+       if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts"))
+               goto cleanup;
+
+       check(skel, link, uprobe_test, uprobe_test, 4);
 
        /* uretprobe */
        skel->bss->executed = 0;
@@ -495,6 +523,7 @@ static void test_uprobe_multi(void)
        LIBBPF_OPTS(bpf_uprobe_multi_opts, opts);
        struct bpf_link *link;
        unsigned long offset;
+       void *tramp;
 
        offset = get_uprobe_offset(&uprobe_test);
        if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
@@ -515,7 +544,28 @@ static void test_uprobe_multi(void)
        if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
                goto cleanup;
 
-       check(skel, link, uprobe_test, uprobe_test, 2);
+       tramp = check(skel, link, uprobe_test, uprobe_test, 2);
+
+       /* reattach and detach without triggering optimization */
+       link = bpf_program__attach_uprobe_multi(skel->progs.test_uprobe_multi,
+                               0, "/proc/self/exe", NULL, &opts);
+       if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
+               goto cleanup;
+
+       bpf_link__destroy(link);
+       if (!check_detach(uprobe_test, tramp))
+               goto cleanup;
+
+       uprobe_test();
+       ASSERT_EQ(skel->bss->executed, 2, "executed_no_probe");
+
+       /* reattach with triggering optimization */
+       link = bpf_program__attach_uprobe_multi(skel->progs.test_uprobe_multi,
+                               0, "/proc/self/exe", NULL, &opts);
+       if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
+               goto cleanup;
+
+       check(skel, link, uprobe_test, uprobe_test, 4);
 
        /* uretprobe.multi */
        skel->bss->executed = 0;
@@ -539,6 +589,7 @@ static void test_uprobe_session(void)
        );
        struct bpf_link *link;
        unsigned long offset;
+       void *tramp;
 
        offset = get_uprobe_offset(&uprobe_test);
        if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
@@ -558,7 +609,28 @@ static void test_uprobe_session(void)
        if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
                goto cleanup;
 
-       check(skel, link, uprobe_test, uprobe_test, 4);
+       tramp = check(skel, link, uprobe_test, uprobe_test, 4);
+
+       /* reattach and detach without triggering optimization */
+       link = bpf_program__attach_uprobe_multi(skel->progs.test_uprobe_session,
+                               0, "/proc/self/exe", NULL, &opts);
+       if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
+               goto cleanup;
+
+       bpf_link__destroy(link);
+       if (!check_detach(uprobe_test, tramp))
+               goto cleanup;
+
+       uprobe_test();
+       ASSERT_EQ(skel->bss->executed, 4, "executed_no_probe");
+
+       /* reattach with triggering optimization */
+       link = bpf_program__attach_uprobe_multi(skel->progs.test_uprobe_session,
+                               0, "/proc/self/exe", NULL, &opts);
+       if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
+               goto cleanup;
+
+       check(skel, link, uprobe_test, uprobe_test, 8);
 
 cleanup:
        uprobe_syscall_executed__destroy(skel);
@@ -568,7 +640,7 @@ static void test_uprobe_usdt(void)
 {
        struct uprobe_syscall_executed *skel;
        struct bpf_link *link;
-       void *addr;
+       void *addr, *tramp;
 
        errno = 0;
        addr = find_nop10(usdt_test);
@@ -587,7 +659,30 @@ static void test_uprobe_usdt(void)
        if (!ASSERT_OK_PTR(link, "bpf_program__attach_usdt"))
                goto cleanup;
 
-       check(skel, link, usdt_test, addr, 2);
+       tramp = check(skel, link, usdt_test, addr, 2);
+
+       /* reattach and detach without triggering optimization */
+       link = bpf_program__attach_usdt(skel->progs.test_usdt,
+                               -1 /* all PIDs */, "/proc/self/exe",
+                               "optimized_uprobe", "usdt", NULL);
+       if (!ASSERT_OK_PTR(link, "bpf_program__attach_usdt"))
+               goto cleanup;
+
+       bpf_link__destroy(link);
+       if (!check_detach(addr, tramp))
+               goto cleanup;
+
+       usdt_test();
+       ASSERT_EQ(skel->bss->executed, 2, "executed_no_probe");
+
+       /* reattach with triggering optimization */
+       link = bpf_program__attach_usdt(skel->progs.test_usdt,
+                               -1 /* all PIDs */, "/proc/self/exe",
+                               "optimized_uprobe", "usdt", NULL);
+       if (!ASSERT_OK_PTR(link, "bpf_program__attach_usdt"))
+               goto cleanup;
+
+       check(skel, link, usdt_test, addr, 4);
 
 cleanup:
        uprobe_syscall_executed__destroy(skel);
-- 
2.53.0


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