[PATCH stable 6.0 0/8] bpf: Fix kprobe_multi link attachment to kernel modules

[PATCH stable 6.0 0/8] bpf: Fix kprobe_multi link attachment to kernel modules

[Jiri Olsa]

hi,
sending fixes for attaching bpf kprobe_multi link to kernel
modules for stable 6.0. It all applies cleanly. 

thanks,
jirka


---
Jiri Olsa (8):
      kallsyms: Make module_kallsyms_on_each_symbol generally available
      ftrace: Add support to resolve module symbols in ftrace_lookup_symbols
      bpf: Rename __bpf_kprobe_multi_cookie_cmp to bpf_kprobe_multi_addrs_cmp
      bpf: Take module reference on kprobe_multi link
      selftests/bpf: Add load_kallsyms_refresh function
      selftests/bpf: Add bpf_testmod_fentry_* functions
      selftests/bpf: Add kprobe_multi check to module attach test
      selftests/bpf: Add kprobe_multi kmod attach api tests

 include/linux/module.h                                             |  9 ++++++++
 kernel/module/kallsyms.c                                           |  2 --
 kernel/trace/bpf_trace.c                                           | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 kernel/trace/ftrace.c                                              | 16 +++++++++-----
 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c              | 24 +++++++++++++++++++++
 tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tools/testing/selftests/bpf/prog_tests/module_attach.c             |  7 +++++++
 tools/testing/selftests/bpf/progs/kprobe_multi.c                   | 50 +++++++++++++++++++++++++++++++++++++++++++
 tools/testing/selftests/bpf/progs/test_module_attach.c             |  6 ++++++
 tools/testing/selftests/bpf/trace_helpers.c                        | 20 +++++++++++-------
 tools/testing/selftests/bpf/trace_helpers.h                        |  2 ++
 11 files changed, 306 insertions(+), 17 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c

[PATCH stable 6.0 1/8] kallsyms: Make module_kallsyms_on_each_symbol generally available

[Jiri Olsa]

commit 73feb8d5fa3b755bb51077c0aabfb6aa556fd498 upstream.

Making module_kallsyms_on_each_symbol generally available, so it
can be used outside CONFIG_LIVEPATCH option in following changes.

Rather than adding another ifdef option let's make the function
generally available (when CONFIG_KALLSYMS and CONFIG_MODULES
options are defined).

Cc: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 include/linux/module.h   | 9 +++++++++
 kernel/module/kallsyms.c | 2 --
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 518296ea7f73..e72db35fbf75 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -879,8 +879,17 @@ static inline bool module_sig_ok(struct module *module)
 }
 #endif	/* CONFIG_MODULE_SIG */
 
+#if defined(CONFIG_MODULES) && defined(CONFIG_KALLSYMS)
 int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 					     struct module *, unsigned long),
 				   void *data);
+#else
+static inline int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
+						 struct module *, unsigned long),
+						 void *data)
+{
+	return -EOPNOTSUPP;
+}
+#endif  /* CONFIG_MODULES && CONFIG_KALLSYMS */
 
 #endif /* _LINUX_MODULE_H */
diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c
index f5c5c9175333..4523f99b0358 100644
--- a/kernel/module/kallsyms.c
+++ b/kernel/module/kallsyms.c
@@ -494,7 +494,6 @@ unsigned long module_kallsyms_lookup_name(const char *name)
 	return ret;
 }
 
-#ifdef CONFIG_LIVEPATCH
 int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 					     struct module *, unsigned long),
 				   void *data)
@@ -531,4 +530,3 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	mutex_unlock(&module_mutex);
 	return ret;
 }
-#endif /* CONFIG_LIVEPATCH */
-- 
2.38.1

[PATCH stable 6.0 2/8] ftrace: Add support to resolve module symbols in ftrace_lookup_symbols

[Jiri Olsa]

commit 3640bf8584f4ab0f5eed6285f09213954acd8b62 upstream.

Currently ftrace_lookup_symbols iterates only over core symbols,
adding module_kallsyms_on_each_symbol call to check on modules
symbols as well.

Also removing 'args.found == args.cnt' condition, because it's
already checked in kallsyms_callback function.

Also removing 'err < 0' check, because both *kallsyms_on_each_symbol
functions do not return error.

Reported-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 kernel/trace/ftrace.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 9e6231f4a04f..768306ec3c94 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -8261,6 +8261,10 @@ struct kallsyms_data {
 	size_t found;
 };
 
+/* This function gets called for all kernel and module symbols
+ * and returns 1 in case we resolved all the requested symbols,
+ * 0 otherwise.
+ */
 static int kallsyms_callback(void *data, const char *name,
 			     struct module *mod, unsigned long addr)
 {
@@ -8304,17 +8308,19 @@ static int kallsyms_callback(void *data, const char *name,
 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
 {
 	struct kallsyms_data args;
-	int err;
+	int found_all;
 
 	memset(addrs, 0, sizeof(*addrs) * cnt);
 	args.addrs = addrs;
 	args.syms = sorted_syms;
 	args.cnt = cnt;
 	args.found = 0;
-	err = kallsyms_on_each_symbol(kallsyms_callback, &args);
-	if (err < 0)
-		return err;
-	return args.found == args.cnt ? 0 : -ESRCH;
+
+	found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
+	if (found_all)
+		return 0;
+	found_all = module_kallsyms_on_each_symbol(kallsyms_callback, &args);
+	return found_all ? 0 : -ESRCH;
 }
 
 #ifdef CONFIG_SYSCTL
-- 
2.38.1

[PATCH stable 6.0 3/8] bpf: Rename __bpf_kprobe_multi_cookie_cmp to bpf_kprobe_multi_addrs_cmp

[Jiri Olsa]

commit 1a1b0716d36d21f8448bd7d3f1c0ade7230bb294 upstream.

Renaming __bpf_kprobe_multi_cookie_cmp to bpf_kprobe_multi_addrs_cmp,
because it's more suitable to current and upcoming code.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 kernel/trace/bpf_trace.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index ec4b81007796..5f3a65ab6ba3 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2362,7 +2362,7 @@ static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void
 	swap(*cookie_a, *cookie_b);
 }
 
-static int __bpf_kprobe_multi_cookie_cmp(const void *a, const void *b)
+static int bpf_kprobe_multi_addrs_cmp(const void *a, const void *b)
 {
 	const unsigned long *addr_a = a, *addr_b = b;
 
@@ -2373,7 +2373,7 @@ static int __bpf_kprobe_multi_cookie_cmp(const void *a, const void *b)
 
 static int bpf_kprobe_multi_cookie_cmp(const void *a, const void *b, const void *priv)
 {
-	return __bpf_kprobe_multi_cookie_cmp(a, b);
+	return bpf_kprobe_multi_addrs_cmp(a, b);
 }
 
 static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx)
@@ -2391,7 +2391,7 @@ static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx)
 		return 0;
 	entry_ip = run_ctx->entry_ip;
 	addr = bsearch(&entry_ip, link->addrs, link->cnt, sizeof(entry_ip),
-		       __bpf_kprobe_multi_cookie_cmp);
+		       bpf_kprobe_multi_addrs_cmp);
 	if (!addr)
 		return 0;
 	cookie = link->cookies + (addr - link->addrs);
-- 
2.38.1

[PATCH stable 6.0 4/8] bpf: Take module reference on kprobe_multi link

[Jiri Olsa]

commit e22061b2d3095c12f90336479f24bf5eeb70e1bd upstream.

Currently we allow to create kprobe multi link on function from kernel
module, but we don't take the module reference to ensure it's not
unloaded while we are tracing it.

The multi kprobe link is based on fprobe/ftrace layer which takes
different approach and releases ftrace hooks when module is unloaded
even if there's tracer registered on top of it.

Adding code that gathers all the related modules for the link and takes
their references before it's attached. All kernel module references are
released after link is unregistered.

Note that we do it the same way already for trampoline probes
(but for single address).

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 kernel/trace/bpf_trace.c | 92 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 5f3a65ab6ba3..da8e7b695179 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2264,6 +2264,8 @@ struct bpf_kprobe_multi_link {
 	unsigned long *addrs;
 	u64 *cookies;
 	u32 cnt;
+	u32 mods_cnt;
+	struct module **mods;
 };
 
 struct bpf_kprobe_multi_run_ctx {
@@ -2319,6 +2321,14 @@ static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32
 	return err;
 }
 
+static void kprobe_multi_put_modules(struct module **mods, u32 cnt)
+{
+	u32 i;
+
+	for (i = 0; i < cnt; i++)
+		module_put(mods[i]);
+}
+
 static void free_user_syms(struct user_syms *us)
 {
 	kvfree(us->syms);
@@ -2331,6 +2341,7 @@ static void bpf_kprobe_multi_link_release(struct bpf_link *link)
 
 	kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
 	unregister_fprobe(&kmulti_link->fp);
+	kprobe_multi_put_modules(kmulti_link->mods, kmulti_link->mods_cnt);
 }
 
 static void bpf_kprobe_multi_link_dealloc(struct bpf_link *link)
@@ -2340,6 +2351,7 @@ static void bpf_kprobe_multi_link_dealloc(struct bpf_link *link)
 	kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
 	kvfree(kmulti_link->addrs);
 	kvfree(kmulti_link->cookies);
+	kfree(kmulti_link->mods);
 	kfree(kmulti_link);
 }
 
@@ -2475,6 +2487,71 @@ static void symbols_swap_r(void *a, void *b, int size, const void *priv)
 	}
 }
 
+struct module_addr_args {
+	unsigned long *addrs;
+	u32 addrs_cnt;
+	struct module **mods;
+	int mods_cnt;
+	int mods_cap;
+};
+
+static int module_callback(void *data, const char *name,
+			   struct module *mod, unsigned long addr)
+{
+	struct module_addr_args *args = data;
+	struct module **mods;
+
+	/* We iterate all modules symbols and for each we:
+	 * - search for it in provided addresses array
+	 * - if found we check if we already have the module pointer stored
+	 *   (we iterate modules sequentially, so we can check just the last
+	 *   module pointer)
+	 * - take module reference and store it
+	 */
+	if (!bsearch(&addr, args->addrs, args->addrs_cnt, sizeof(addr),
+		       bpf_kprobe_multi_addrs_cmp))
+		return 0;
+
+	if (args->mods && args->mods[args->mods_cnt - 1] == mod)
+		return 0;
+
+	if (args->mods_cnt == args->mods_cap) {
+		args->mods_cap = max(16, args->mods_cap * 3 / 2);
+		mods = krealloc_array(args->mods, args->mods_cap, sizeof(*mods), GFP_KERNEL);
+		if (!mods)
+			return -ENOMEM;
+		args->mods = mods;
+	}
+
+	if (!try_module_get(mod))
+		return -EINVAL;
+
+	args->mods[args->mods_cnt] = mod;
+	args->mods_cnt++;
+	return 0;
+}
+
+static int get_modules_for_addrs(struct module ***mods, unsigned long *addrs, u32 addrs_cnt)
+{
+	struct module_addr_args args = {
+		.addrs     = addrs,
+		.addrs_cnt = addrs_cnt,
+	};
+	int err;
+
+	/* We return either err < 0 in case of error, ... */
+	err = module_kallsyms_on_each_symbol(module_callback, &args);
+	if (err) {
+		kprobe_multi_put_modules(args.mods, args.mods_cnt);
+		kfree(args.mods);
+		return err;
+	}
+
+	/* or number of modules found if everything is ok. */
+	*mods = args.mods;
+	return args.mods_cnt;
+}
+
 int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 {
 	struct bpf_kprobe_multi_link *link = NULL;
@@ -2585,10 +2662,25 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 		       bpf_kprobe_multi_cookie_cmp,
 		       bpf_kprobe_multi_cookie_swap,
 		       link);
+	} else {
+		/*
+		 * We need to sort addrs array even if there are no cookies
+		 * provided, to allow bsearch in get_modules_for_addrs.
+		 */
+		sort(addrs, cnt, sizeof(*addrs),
+		       bpf_kprobe_multi_addrs_cmp, NULL);
+	}
+
+	err = get_modules_for_addrs(&link->mods, addrs, cnt);
+	if (err < 0) {
+		bpf_link_cleanup(&link_primer);
+		return err;
 	}
+	link->mods_cnt = err;
 
 	err = register_fprobe_ips(&link->fp, addrs, cnt);
 	if (err) {
+		kprobe_multi_put_modules(link->mods, link->mods_cnt);
 		bpf_link_cleanup(&link_primer);
 		return err;
 	}
-- 
2.38.1

[PATCH stable 6.0 5/8] selftests/bpf: Add load_kallsyms_refresh function

[Jiri Olsa]

commit 10705b2b7a8e4eb46ab5bf1b9ee354cb9a929428 upstream.

Adding load_kallsyms_refresh function to re-read symbols from
/proc/kallsyms file.

This will be needed to get proper functions addresses from
bpf_testmod.ko module, which is loaded/unloaded several times
during the tests run, so symbols might be already old when
we need to use them.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-6-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 tools/testing/selftests/bpf/trace_helpers.c | 20 +++++++++++++-------
 tools/testing/selftests/bpf/trace_helpers.h |  2 ++
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index 9c4be2cdb21a..09a16a77bae4 100644
--- a/tools/testing/selftests/bpf/trace_helpers.c
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -23,7 +23,7 @@ static int ksym_cmp(const void *p1, const void *p2)
 	return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
 }
 
-int load_kallsyms(void)
+int load_kallsyms_refresh(void)
 {
 	FILE *f;
 	char func[256], buf[256];
@@ -31,12 +31,7 @@ int load_kallsyms(void)
 	void *addr;
 	int i = 0;
 
-	/*
-	 * This is called/used from multiplace places,
-	 * load symbols just once.
-	 */
-	if (sym_cnt)
-		return 0;
+	sym_cnt = 0;
 
 	f = fopen("/proc/kallsyms", "r");
 	if (!f)
@@ -57,6 +52,17 @@ int load_kallsyms(void)
 	return 0;
 }
 
+int load_kallsyms(void)
+{
+	/*
+	 * This is called/used from multiplace places,
+	 * load symbols just once.
+	 */
+	if (sym_cnt)
+		return 0;
+	return load_kallsyms_refresh();
+}
+
 struct ksym *ksym_search(long key)
 {
 	int start = 0, end = sym_cnt;
diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
index 238a9c98cde2..53efde0e2998 100644
--- a/tools/testing/selftests/bpf/trace_helpers.h
+++ b/tools/testing/selftests/bpf/trace_helpers.h
@@ -10,6 +10,8 @@ struct ksym {
 };
 
 int load_kallsyms(void);
+int load_kallsyms_refresh(void);
+
 struct ksym *ksym_search(long key);
 long ksym_get_addr(const char *name);
 
-- 
2.38.1

[PATCH stable 6.0 6/8] selftests/bpf: Add bpf_testmod_fentry_* functions

[Jiri Olsa]

commit fee356ede980b6c2c8db612e18b25738356d6744 upstream.

Adding 3 bpf_testmod_fentry_* functions to have a way to test
kprobe multi link on kernel module. They follow bpf_fentry_test*
functions prototypes/code.

Adding equivalent functions to all bpf_fentry_test* does not
seems necessary at the moment, could be added later.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-7-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 .../selftests/bpf/bpf_testmod/bpf_testmod.c   | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 792cb15bac40..ac5d7c1396fb 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -88,6 +88,23 @@ __weak noinline struct file *bpf_testmod_return_ptr(int arg)
 	}
 }
 
+noinline int bpf_testmod_fentry_test1(int a)
+{
+	return a + 1;
+}
+
+noinline int bpf_testmod_fentry_test2(int a, u64 b)
+{
+	return a + b;
+}
+
+noinline int bpf_testmod_fentry_test3(char a, int b, u64 c)
+{
+	return a + b + c;
+}
+
+int bpf_testmod_fentry_ok;
+
 noinline ssize_t
 bpf_testmod_test_read(struct file *file, struct kobject *kobj,
 		      struct bin_attribute *bin_attr,
@@ -119,6 +136,13 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj,
 			return snprintf(buf, len, "%d\n", writable.val);
 	}
 
+	if (bpf_testmod_fentry_test1(1) != 2 ||
+	    bpf_testmod_fentry_test2(2, 3) != 5 ||
+	    bpf_testmod_fentry_test3(4, 5, 6) != 15)
+		goto out;
+
+	bpf_testmod_fentry_ok = 1;
+out:
 	return -EIO; /* always fail */
 }
 EXPORT_SYMBOL(bpf_testmod_test_read);
-- 
2.38.1

[PATCH stable 6.0 7/8] selftests/bpf: Add kprobe_multi check to module attach test

[Jiri Olsa]

commit e697d8dcebd2f557fa5e5ed57aaf0a9992ce9df8 upstream.

Adding test that makes sure the kernel module won't be removed
if there's kprobe multi link defined on top of it.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-8-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 tools/testing/selftests/bpf/prog_tests/module_attach.c | 7 +++++++
 tools/testing/selftests/bpf/progs/test_module_attach.c | 6 ++++++
 2 files changed, 13 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/module_attach.c b/tools/testing/selftests/bpf/prog_tests/module_attach.c
index 6d0e50dcf47c..7fc01ff490db 100644
--- a/tools/testing/selftests/bpf/prog_tests/module_attach.c
+++ b/tools/testing/selftests/bpf/prog_tests/module_attach.c
@@ -103,6 +103,13 @@ void test_module_attach(void)
 	ASSERT_ERR(delete_module("bpf_testmod", 0), "delete_module");
 	bpf_link__destroy(link);
 
+	link = bpf_program__attach(skel->progs.kprobe_multi);
+	if (!ASSERT_OK_PTR(link, "attach_kprobe_multi"))
+		goto cleanup;
+
+	ASSERT_ERR(delete_module("bpf_testmod", 0), "delete_module");
+	bpf_link__destroy(link);
+
 cleanup:
 	test_module_attach__destroy(skel);
 }
diff --git a/tools/testing/selftests/bpf/progs/test_module_attach.c b/tools/testing/selftests/bpf/progs/test_module_attach.c
index 08628afedb77..8a1b50f3a002 100644
--- a/tools/testing/selftests/bpf/progs/test_module_attach.c
+++ b/tools/testing/selftests/bpf/progs/test_module_attach.c
@@ -110,4 +110,10 @@ int BPF_PROG(handle_fmod_ret,
 	return 0; /* don't override the exit code */
 }
 
+SEC("kprobe.multi/bpf_testmod_test_read")
+int BPF_PROG(kprobe_multi)
+{
+	return 0;
+}
+
 char _license[] SEC("license") = "GPL";
-- 
2.38.1

[PATCH stable 6.0 8/8] selftests/bpf: Add kprobe_multi kmod attach api tests

[Jiri Olsa]

commit be884a22c1c835a146e97c6ab282a2b31b002e1f upstream.

Adding kprobe_multi kmod attach api tests that attach bpf_testmod
functions via bpf_program__attach_kprobe_multi_opts.

Running it as serial test, because we don't want other tests to
reload bpf_testmod while it's running.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-9-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 .../prog_tests/kprobe_multi_testmod_test.c    | 89 +++++++++++++++++++
 .../selftests/bpf/progs/kprobe_multi.c        | 50 +++++++++++
 2 files changed, 139 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c

diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c
new file mode 100644
index 000000000000..1fbe7e4ac00a
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "kprobe_multi.skel.h"
+#include "trace_helpers.h"
+#include "bpf/libbpf_internal.h"
+
+static void kprobe_multi_testmod_check(struct kprobe_multi *skel)
+{
+	ASSERT_EQ(skel->bss->kprobe_testmod_test1_result, 1, "kprobe_test1_result");
+	ASSERT_EQ(skel->bss->kprobe_testmod_test2_result, 1, "kprobe_test2_result");
+	ASSERT_EQ(skel->bss->kprobe_testmod_test3_result, 1, "kprobe_test3_result");
+
+	ASSERT_EQ(skel->bss->kretprobe_testmod_test1_result, 1, "kretprobe_test1_result");
+	ASSERT_EQ(skel->bss->kretprobe_testmod_test2_result, 1, "kretprobe_test2_result");
+	ASSERT_EQ(skel->bss->kretprobe_testmod_test3_result, 1, "kretprobe_test3_result");
+}
+
+static void test_testmod_attach_api(struct bpf_kprobe_multi_opts *opts)
+{
+	struct kprobe_multi *skel = NULL;
+
+	skel = kprobe_multi__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "fentry_raw_skel_load"))
+		return;
+
+	skel->bss->pid = getpid();
+
+	skel->links.test_kprobe_testmod = bpf_program__attach_kprobe_multi_opts(
+						skel->progs.test_kprobe_testmod,
+						NULL, opts);
+	if (!skel->links.test_kprobe_testmod)
+		goto cleanup;
+
+	opts->retprobe = true;
+	skel->links.test_kretprobe_testmod = bpf_program__attach_kprobe_multi_opts(
+						skel->progs.test_kretprobe_testmod,
+						NULL, opts);
+	if (!skel->links.test_kretprobe_testmod)
+		goto cleanup;
+
+	ASSERT_OK(trigger_module_test_read(1), "trigger_read");
+	kprobe_multi_testmod_check(skel);
+
+cleanup:
+	kprobe_multi__destroy(skel);
+}
+
+static void test_testmod_attach_api_addrs(void)
+{
+	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+	unsigned long long addrs[3];
+
+	addrs[0] = ksym_get_addr("bpf_testmod_fentry_test1");
+	ASSERT_NEQ(addrs[0], 0, "ksym_get_addr");
+	addrs[1] = ksym_get_addr("bpf_testmod_fentry_test2");
+	ASSERT_NEQ(addrs[1], 0, "ksym_get_addr");
+	addrs[2] = ksym_get_addr("bpf_testmod_fentry_test3");
+	ASSERT_NEQ(addrs[2], 0, "ksym_get_addr");
+
+	opts.addrs = (const unsigned long *) addrs;
+	opts.cnt = ARRAY_SIZE(addrs);
+
+	test_testmod_attach_api(&opts);
+}
+
+static void test_testmod_attach_api_syms(void)
+{
+	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+	const char *syms[3] = {
+		"bpf_testmod_fentry_test1",
+		"bpf_testmod_fentry_test2",
+		"bpf_testmod_fentry_test3",
+	};
+
+	opts.syms = syms;
+	opts.cnt = ARRAY_SIZE(syms);
+	test_testmod_attach_api(&opts);
+}
+
+void serial_test_kprobe_multi_testmod_test(void)
+{
+	if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
+		return;
+
+	if (test__start_subtest("testmod_attach_api_syms"))
+		test_testmod_attach_api_syms();
+	if (test__start_subtest("testmod_attach_api_addrs"))
+		test_testmod_attach_api_addrs();
+}
diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi.c b/tools/testing/selftests/bpf/progs/kprobe_multi.c
index 98c3399e15c0..9e1ca8e34913 100644
--- a/tools/testing/selftests/bpf/progs/kprobe_multi.c
+++ b/tools/testing/selftests/bpf/progs/kprobe_multi.c
@@ -110,3 +110,53 @@ int test_kretprobe_manual(struct pt_regs *ctx)
 	kprobe_multi_check(ctx, true);
 	return 0;
 }
+
+extern const void bpf_testmod_fentry_test1 __ksym;
+extern const void bpf_testmod_fentry_test2 __ksym;
+extern const void bpf_testmod_fentry_test3 __ksym;
+
+__u64 kprobe_testmod_test1_result = 0;
+__u64 kprobe_testmod_test2_result = 0;
+__u64 kprobe_testmod_test3_result = 0;
+
+__u64 kretprobe_testmod_test1_result = 0;
+__u64 kretprobe_testmod_test2_result = 0;
+__u64 kretprobe_testmod_test3_result = 0;
+
+static void kprobe_multi_testmod_check(void *ctx, bool is_return)
+{
+	if (bpf_get_current_pid_tgid() >> 32 != pid)
+		return;
+
+	__u64 addr = bpf_get_func_ip(ctx);
+
+	if (is_return) {
+		if ((const void *) addr == &bpf_testmod_fentry_test1)
+			kretprobe_testmod_test1_result = 1;
+		if ((const void *) addr == &bpf_testmod_fentry_test2)
+			kretprobe_testmod_test2_result = 1;
+		if ((const void *) addr == &bpf_testmod_fentry_test3)
+			kretprobe_testmod_test3_result = 1;
+	} else {
+		if ((const void *) addr == &bpf_testmod_fentry_test1)
+			kprobe_testmod_test1_result = 1;
+		if ((const void *) addr == &bpf_testmod_fentry_test2)
+			kprobe_testmod_test2_result = 1;
+		if ((const void *) addr == &bpf_testmod_fentry_test3)
+			kprobe_testmod_test3_result = 1;
+	}
+}
+
+SEC("kprobe.multi")
+int test_kprobe_testmod(struct pt_regs *ctx)
+{
+	kprobe_multi_testmod_check(ctx, false);
+	return 0;
+}
+
+SEC("kretprobe.multi")
+int test_kretprobe_testmod(struct pt_regs *ctx)
+{
+	kprobe_multi_testmod_check(ctx, true);
+	return 0;
+}
-- 
2.38.1

Re: [PATCH stable 6.0 0/8] bpf: Fix kprobe_multi link attachment to kernel modules

[Greg KH]

On Fri, Dec 16, 2022 at 01:56:20PM +0100, Jiri Olsa wrote:
> hi,
> sending fixes for attaching bpf kprobe_multi link to kernel
> modules for stable 6.0. It all applies cleanly. 

All now queued up, thanks.

greg k-h