Merge branch 'bpf: Fixes for kprobe multi on kernel modules'

Jiri Olsa says:

====================

hi,
Martynas reported kprobe _multi link does not resolve symbols
from kernel modules, which attach by address works.

In addition while fixing that I realized we do not take module
reference if the module has kprobe_multi link on top of it and
can be removed.

There's mo crash related to this, it will silently disappear from
ftrace tables, while kprobe_multi link stays up with no data.

This patchset has fixes for both issues.

v3 changes:
  - reorder fields in struct bpf_kprobe_multi_link [Andrii]
  - added ack [Andrii]

v2 changes:
  - added acks (Song)
  - added comment to kallsyms_callback (Song)
  - change module_callback realloc logic (Andrii)
  - get rid of macros in tests (Andrii)

thanks,
jirka
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/module.h b/include/linux/module.h
index ec61fb53979a..35876e89eb93 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 */