Re: [RFC V2] mm: Generalize notify_page_fault()

Peter Zijlstra
2019-06-04T06:54:01Z

On Tue, Jun 04, 2019 at 12:04:06PM +0530, Anshuman Khandual wrote:
> diff --git a/mm/memory.c b/mm/memory.c
> index ddf20bd..b6bae8f 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -52,6 +52,7 @@
> #include <linux/pagemap.h>
> #include <linux/memremap.h>
> #include <linux/ksm.h>
> +#include <linux/kprobes.h>
> #include <linux/rmap.h>
> #include <linux/export.h>
> #include <linux/delayacct.h>
> @@ -141,6 +142,21 @@ static int __init init_zero_pfn(void)
> core_initcall(init_zero_pfn);
>
>
> +int __kprobes notify_page_fault(struct pt_regs *regs, unsigned int trap)
> +{
> + int ret = 0;
> +
> + /*
> + * To be potentially processing a kprobe fault and to be allowed
> + * to call kprobe_running(), we have to be non-preemptible.
> + */
> + if (kprobes_built_in() && !preemptible() && !user_mode(regs)) {
> + if (kprobe_running() && kprobe_fault_handler(regs, trap))
> + ret = 1;
> + }
> + return ret;
> +}

That thing should be called kprobe_page_fault() or something,
notify_page_fault() is a horribly crap name for this function.