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authorJessica Yu <jeyu@redhat.com>2016-02-16 17:32:33 -0500
committerJiri Kosina <jkosina@suse.cz>2016-02-17 22:14:06 +0100
commit7dcd182bec271ab341b05b66b6006995795fc0e7 (patch)
treeb2850092d0b57e9c33bb8743ca5053ca6404552d /include
parent383bf44d1a8b18de5c26ec2a48c6822681b50984 (diff)
ftrace/module: remove ftrace module notifier
Remove the ftrace module notifier in favor of directly calling ftrace_module_enable() and ftrace_release_mod() in the module loader. Hard-coding the function calls directly in the module loader removes dependence on the module notifier call chain and provides better visibility and control over what gets called when, which is important to kernel utilities such as livepatch. This fixes a notifier ordering issue in which the ftrace module notifier (and hence ftrace_module_enable()) for coming modules was being called after klp_module_notify(), which caused livepatch modules to initialize incorrectly. This patch removes dependence on the module notifier call chain in favor of hard coding the corresponding function calls in the module loader. This ensures that ftrace and livepatch code get called in the correct order on patch module load and unload. Fixes: 5156dca34a3e ("ftrace: Fix the race between ftrace and insmod") Signed-off-by: Jessica Yu <jeyu@redhat.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Petr Mladek <pmladek@suse.cz> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'include')
-rw-r--r--include/linux/ftrace.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 0639dcc98195..76dc15e171eb 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -604,6 +604,7 @@ extern int ftrace_arch_read_dyn_info(char *buf, int size);
extern int skip_trace(unsigned long ip);
extern void ftrace_module_init(struct module *mod);
+extern void ftrace_module_enable(struct module *mod);
extern void ftrace_release_mod(struct module *mod);
extern void ftrace_disable_daemon(void);
@@ -613,8 +614,9 @@ static inline int skip_trace(unsigned long ip) { return 0; }
static inline int ftrace_force_update(void) { return 0; }
static inline void ftrace_disable_daemon(void) { }
static inline void ftrace_enable_daemon(void) { }
-static inline void ftrace_release_mod(struct module *mod) {}
-static inline void ftrace_module_init(struct module *mod) {}
+static inline void ftrace_module_init(struct module *mod) { }
+static inline void ftrace_module_enable(struct module *mod) { }
+static inline void ftrace_release_mod(struct module *mod) { }
static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
{
return -EINVAL;