Re: [PATCH 3.10 12/27] x86-64, espfix: Dont leak bits 31:16 of %esp returning to 16-bit stack

From: Luis Henriques
Date: Wed Aug 06 2014 - 11:16:31 EST


On Tue, Aug 05, 2014 at 11:14:04AM -0700, Greg Kroah-Hartman wrote:
<...>
> @@ -188,17 +193,21 @@ static void note_page(struct seq_file *m
> /*
> * Now print the actual finished series
> */
> - seq_printf(m, "0x%0*lx-0x%0*lx ",
> - width, st->start_address,
> - width, st->current_address);
> -
> - delta = (st->current_address - st->start_address) >> 10;
> - while (!(delta & 1023) && unit[1]) {
> - delta >>= 10;
> - unit++;
> + if (!st->marker->max_lines ||
> + st->lines < st->marker->max_lines) {
> + seq_printf(m, "0x%0*lx-0x%0*lx ",
> + width, st->start_address,
> + width, st->current_address);
> +
> + delta = (st->current_address - st->start_address) >> 10;
> + while (!(delta & 1023) && unit[1]) {
> + delta >>= 10;
> + unit++;
> + }
> + seq_printf(m, "%9lu%c ", delta, *unit);
> + printk_prot(m, st->current_prot, st->level);
> }
> - seq_printf(m, "%9lu%c ", delta, *unit);
> - printk_prot(m, st->current_prot, st->level);
> + st->lines++;
>
> /*
> * We print markers for special areas of address space,

Hmm... the original commit has a 2nd hunk here that does seem to be
applicable to 3.10. Was this dropped accidentally or on purpose?

Cheers,
--
Luís

> --- a/init/main.c
> +++ b/init/main.c
> @@ -606,6 +606,10 @@ asmlinkage void __init start_kernel(void
> if (efi_enabled(EFI_RUNTIME_SERVICES))
> efi_enter_virtual_mode();
> #endif
> +#ifdef CONFIG_X86_64
> + /* Should be run before the first non-init thread is created */
> + init_espfix_bsp();
> +#endif
> thread_info_cache_init();
> cred_init();
> fork_init(totalram_pages);
>
>
> --
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