On 08/08/2016 09:40 PM, Thomas Garnier wrote: > Default implementation expects 6 pages maximum are needed for low page > allocations. If KASLR memory randomization is enabled, the worse case > of e820 layout would require 12 pages (no large pages). It is due to the > PUD level randomization and the variable e820 memory layout. > > This bug was found while doing extensive testing of KASLR memory > randomization on different type of hardware. > > Signed-off-by: Thomas Garnier <thgar...@google.com> > --- > Based on next-20160805 > --- > arch/x86/mm/init.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c > index 6209289..3a27e6a 100644 > --- a/arch/x86/mm/init.c > +++ b/arch/x86/mm/init.c > @@ -130,6 +130,14 @@ void __init early_alloc_pgt_buf(void) > unsigned long tables = INIT_PGT_BUF_SIZE; > phys_addr_t base; > > + /* > + * Depending on the machine e860 memory layout and the PUD alignement. > + * We may need twice more pages when KASLR memoy randomization is > + * enabled. > + */ > + if (IS_ENABLED(CONFIG_RANDOMIZE_MEMORY)) > + tables *= 2; > + > base = __pa(extend_brk(tables, PAGE_SIZE)); > > pgt_buf_start = base >> PAGE_SHIFT; >
You should increase the reserve also : RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE); --Mika
