On Mon, 1 Jun 2020 19:45:51 +0100 Jules Irenge <[email protected]> wrote:
> Sparse reports warnings > > warning: context imbalance in ftrace_arch_code_modify_prepare() > - wrong count at exit > warning: context imbalance in ftrace_arch_code_modify_post_process() > - wrong count at exit > > The root cause is that even if > the annotations on the function are correct, > mutex do not support annotation > This makes Sparse to complain. > To fix this, > __acquire(&text_mutex) and > __release(&text_mutex) annotations are added > inside ftrace_arch_code_modify_prepare() > and ftrace_arch_code_modify_post_process() > respectively. Wait what? This looks like either a bug in sparse, or we just remove the annotations. This just makes the code ugly, and looks silly. Nack! -- Steve > > Signed-off-by: Jules Irenge <[email protected]> > --- > arch/x86/kernel/ftrace.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c > index 37a0aeaf89e7..737c07ab2e07 100644 > --- a/arch/x86/kernel/ftrace.c > +++ b/arch/x86/kernel/ftrace.c > @@ -46,6 +46,7 @@ int ftrace_arch_code_modify_prepare(void) > * ftrace has it set to "read/write". > */ > mutex_lock(&text_mutex); > + __acquire(&text_mutex); > ftrace_poke_late = 1; > return 0; > } > @@ -61,6 +62,7 @@ int ftrace_arch_code_modify_post_process(void) > text_poke_finish(); > ftrace_poke_late = 0; > mutex_unlock(&text_mutex); > + __release(&text_mutex); > return 0; > } >
