On Fri, 24 Jul 2020 08:05:48 +0300
Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> wrote:
> Add lock_modules() and unlock_modules() wrappers for acquiring module_mutex
> in order to remove the compile time dependency to it.
This subject is a bit confusing. This is just wrapping modules_mutex in
kpprobes. We still have compile time dependency, e.g. module_state, right?
Thank you,
>
> Cc: linux-mm@xxxxxxxxx
> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Suggested-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> ---
> include/linux/module.h | 18 ++++++++++++++++++
> kernel/kprobes.c | 4 ++--
> kernel/trace/trace_kprobe.c | 4 ++--
> 3 files changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/module.h b/include/linux/module.h
> index 2e6670860d27..8850b9692b8f 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -705,6 +705,16 @@ static inline bool is_livepatch_module(struct module *mod)
> bool is_module_sig_enforced(void);
> void set_module_sig_enforced(void);
>
> +static inline void lock_modules(void)
> +{
> + mutex_lock(&module_mutex);
> +}
> +
> +static inline void unlock_modules(void)
> +{
> + mutex_unlock(&module_mutex);
> +}
> +
> #else /* !CONFIG_MODULES... */
>
> static inline struct module *__module_address(unsigned long addr)
> @@ -852,6 +862,14 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr)
> return ptr;
> }
>
> +static inline void lock_modules(void)
> +{
> +}
> +
> +static inline void unlock_modules(void)
> +{
> +}
> +
> #endif /* CONFIG_MODULES */
>
> #ifdef CONFIG_SYSFS
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 2e97febeef77..4e46d96d4e16 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -564,7 +564,7 @@ static void kprobe_optimizer(struct work_struct *work)
> cpus_read_lock();
> mutex_lock(&text_mutex);
> /* Lock modules while optimizing kprobes */
> - mutex_lock(&module_mutex);
> + lock_modules();
>
> /*
> * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
> @@ -589,7 +589,7 @@ static void kprobe_optimizer(struct work_struct *work)
> /* Step 4: Free cleaned kprobes after quiesence period */
> do_free_cleaned_kprobes();
>
> - mutex_unlock(&module_mutex);
> + unlock_modules();
> mutex_unlock(&text_mutex);
> cpus_read_unlock();
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index aefb6065b508..710ec6a6aa8f 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -122,9 +122,9 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
> if (!p)
> return true;
> *p = '\0';
> - mutex_lock(&module_mutex);
> + lock_modules();
> ret = !!find_module(tk->symbol);
> - mutex_unlock(&module_mutex);
> + unlock_modules();
> *p = ':';
>
> return ret;
> --
> 2.25.1
>
--
Masami Hiramatsu <mhiramat@xxxxxxxxxx>
