On Mon, Oct 1, 2018 at 7:31 AM, Jann Horn <jannh@xxxxxxxxxx> wrote:
> commit 5dd0b16cdaff ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED
> available even on UP") made the availability of the NR_TLB_REMOTE_FLUSH*
> counters inside the kernel unconditional to reduce #ifdef soup, but
> (either to avoid showing dummy zero counters to userspace, or because that
> code was missed) didn't update the vmstat_array, meaning that all following
> counters would be shown with incorrect values.
>
> This only affects kernel builds with
> CONFIG_VM_EVENT_COUNTERS=y && CONFIG_DEBUG_TLBFLUSH=y && CONFIG_SMP=n.
>
> Fixes: 5dd0b16cdaff ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even on UP")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
-Kees
> ---
> mm/vmstat.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 4cea7b8f519d..7878da76abf2 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1275,6 +1275,9 @@ const char * const vmstat_text[] = {
> #ifdef CONFIG_SMP
> "nr_tlb_remote_flush",
> "nr_tlb_remote_flush_received",
> +#else
> + "", /* nr_tlb_remote_flush */
> + "", /* nr_tlb_remote_flush_received */
> #endif /* CONFIG_SMP */
> "nr_tlb_local_flush_all",
> "nr_tlb_local_flush_one",
> --
> 2.19.0.605.g01d371f741-goog
>
--
Kees Cook
Pixel Security
