[PATCH v3 1/2] ftrace: disable preemption between ftrace_test_recursion_trylock/unlock()
mbenes at suse.cz
Thu Oct 14 02:13:13 PDT 2021
> diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
> index e8029ae..b8d75fb 100644
> --- a/kernel/livepatch/patch.c
> +++ b/kernel/livepatch/patch.c
> @@ -49,14 +49,16 @@ static void notrace klp_ftrace_handler(unsigned long ip,
> ops = container_of(fops, struct klp_ops, fops);
> + /*
> + *
This empty line is not useful.
> + * The ftrace_test_recursion_trylock() will disable preemption,
> + * which is required for the variant of synchronize_rcu() that is
> + * used to allow patching functions where RCU is not watching.
> + * See klp_synchronize_transition() for more details.
> + */
> bit = ftrace_test_recursion_trylock(ip, parent_ip);
> if (WARN_ON_ONCE(bit < 0))
> - /*
> - * A variant of synchronize_rcu() is used to allow patching functions
> - * where RCU is not watching, see klp_synchronize_transition().
> - */
> - preempt_disable_notrace();
> func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
> @@ -120,7 +122,6 @@ static void notrace klp_ftrace_handler(unsigned long ip,
> klp_arch_set_pc(fregs, (unsigned long)func->new_func);
> - preempt_enable_notrace();
Acked-by: Miroslav Benes <mbenes at suse.cz>
for the livepatch part of the patch.
I would also ask you not to submit new versions so often, so that the
other reviewers have time to actually review the patch set.
Quoting from Documentation/process/submitting-patches.rst:
"Wait for a minimum of one week before resubmitting or pinging reviewers -
possibly longer during busy times like merge windows."
More information about the linux-riscv