On Thu, Jun 18, 2020 at 08:43:06AM +0200, Christoph Hellwig wrote:
> Use PAGE_KERNEL_ROX directly instead of allocating RWX and setting the
> page read-only just after the allocation.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> arch/arm64/kernel/probes/kprobes.c | 12 +++---------
> 1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
> index d1c95dcf1d7833..cbe49cd117cfec 100644
> --- a/arch/arm64/kernel/probes/kprobes.c
> +++ b/arch/arm64/kernel/probes/kprobes.c
> @@ -120,15 +120,9 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
>
> void *alloc_insn_page(void)
> {
> - void *page;
> -
> - page = vmalloc_exec(PAGE_SIZE);
> - if (page) {
> - set_memory_ro((unsigned long)page, 1);
> - set_vm_flush_reset_perms(page);
> - }
> -
> - return page;
> + return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
> + GFP_KERNEL, PAGE_KERNEL_ROX, VM_FLUSH_RESET_PERMS,
> + NUMA_NO_NODE, __func__);
> }
I think this has the exact same range issue as the x86 user. But it
might be less fatal if their PLT magic can cover the full range.
