From: Jisheng Zhang Jisheng.Zhang@synaptics.com
commit e69012400b0cb42b2070748322cb72f9effec00f upstream.
When we added KFENCE support for arm64, we intended that it would force the entire linear map to be mapped at page granularity, but we only enforced this in arch_add_memory() and not in map_mem(), so memory mapped at boot time can be mapped at a larger granularity.
When booting a kernel with KFENCE=y and RODATA_FULL=n, this results in the following WARNING at boot:
[ 0.000000] ------------[ cut here ]------------ [ 0.000000] WARNING: CPU: 0 PID: 0 at mm/memory.c:2462 apply_to_pmd_range+0xec/0x190 [ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc1+ #10 [ 0.000000] Hardware name: linux,dummy-virt (DT) [ 0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO BTYPE=--) [ 0.000000] pc : apply_to_pmd_range+0xec/0x190 [ 0.000000] lr : __apply_to_page_range+0x94/0x170 [ 0.000000] sp : ffffffc010573e20 [ 0.000000] x29: ffffffc010573e20 x28: ffffff801f400000 x27: ffffff801f401000 [ 0.000000] x26: 0000000000000001 x25: ffffff801f400fff x24: ffffffc010573f28 [ 0.000000] x23: ffffffc01002b710 x22: ffffffc0105fa450 x21: ffffffc010573ee4 [ 0.000000] x20: ffffff801fffb7d0 x19: ffffff801f401000 x18: 00000000fffffffe [ 0.000000] x17: 000000000000003f x16: 000000000000000a x15: ffffffc01060b940 [ 0.000000] x14: 0000000000000000 x13: 0098968000000000 x12: 0000000098968000 [ 0.000000] x11: 0000000000000000 x10: 0000000098968000 x9 : 0000000000000001 [ 0.000000] x8 : 0000000000000000 x7 : ffffffc010573ee4 x6 : 0000000000000001 [ 0.000000] x5 : ffffffc010573f28 x4 : ffffffc01002b710 x3 : 0000000040000000 [ 0.000000] x2 : ffffff801f5fffff x1 : 0000000000000001 x0 : 007800005f400705 [ 0.000000] Call trace: [ 0.000000] apply_to_pmd_range+0xec/0x190 [ 0.000000] __apply_to_page_range+0x94/0x170 [ 0.000000] apply_to_page_range+0x10/0x20 [ 0.000000] __change_memory_common+0x50/0xdc [ 0.000000] set_memory_valid+0x30/0x40 [ 0.000000] kfence_init_pool+0x9c/0x16c [ 0.000000] kfence_init+0x20/0x98 [ 0.000000] start_kernel+0x284/0x3f8
Fixes: 840b23986344 ("arm64, kfence: enable KFENCE for ARM64") Cc: stable@vger.kernel.org # 5.12.x Signed-off-by: Jisheng Zhang Jisheng.Zhang@synaptics.com Acked-by: Mark Rutland mark.rutland@arm.com Acked-by: Marco Elver elver@google.com Tested-by: Marco Elver elver@google.com Link: https://lore.kernel.org/r/20210525104551.2ec37f77@xhacker.debian Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/mm/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -492,7 +492,8 @@ static void __init map_mem(pgd_t *pgdp) int flags = 0; u64 i;
- if (rodata_full || crash_mem_map || debug_pagealloc_enabled()) + if (rodata_full || crash_mem_map || debug_pagealloc_enabled() || + IS_ENABLED(CONFIG_KFENCE)) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
/*