From: Jiri Kosina jkosina@suse.cz
commit 074376ac0e1d1fcd4fafebca86ee6158e7c20680 upstream.
ftrace_arch_code_modify_prepare() is acquiring text_mutex, while the corresponding release is happening in ftrace_arch_code_modify_post_process().
This has already been documented in the code, but let's also make the fact that this is intentional clear to the semantic analysis tools such as sparse.
Link: http://lkml.kernel.org/r/nycvar.YFH.7.76.1906292321170.27227@cbobk.fhfr.pm
Fixes: 39611265edc1a ("ftrace/x86: Add a comment to why we take text_mutex in ftrace_arch_code_modify_prepare()") Fixes: d5b844a2cf507 ("ftrace/x86: Remove possible deadlock between register_kprobe() and ftrace_run_update_code()") Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Cc: Guenter Roeck linux@roeck-us.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/ftrace.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -36,6 +36,7 @@ #ifdef CONFIG_DYNAMIC_FTRACE
int ftrace_arch_code_modify_prepare(void) + __acquires(&text_mutex) { mutex_lock(&text_mutex); set_kernel_text_rw(); @@ -44,6 +45,7 @@ int ftrace_arch_code_modify_prepare(void }
int ftrace_arch_code_modify_post_process(void) + __releases(&text_mutex) { set_all_modules_text_ro(); set_kernel_text_ro();