kernel: add another missing KASAN symbol

Enabling KERNEL_KASAN exposes yet another missing symbol. This did not
appear on bcm27xx but is appearing now on x86/64. Add a new kernel build
option for KASAN_VMALLOC to fix build on x86/64 with KERNEL_KASAN
enabled.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
This commit is contained in:
Stijn Tintel 2021-11-07 18:33:35 +02:00
parent da9a8fcbc3
commit cbeab2cd99

View File

@ -170,6 +170,22 @@ config KERNEL_KASAN_EXTRA
compile time.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
CONFIG KERNEL_KASAN_VMALLOC
bool "Back mappings in vmalloc space with real shadow memory"
depends on KERNEL_KASAN
By default, the shadow region for vmalloc space is the read-only
zero page. This means that KASAN cannot detect errors involving
vmalloc space.
Enabling this option will hook in to vmap/vmalloc and back those
mappings with real shadow memory allocated on demand. This allows
for KASAN to detect more sorts of errors (and to support vmapped
stacks), but at the cost of higher memory usage.
This option depends on HAVE_ARCH_KASAN_VMALLOC, but we can't
depend on that in here, so it is possible that enabling this
will have no effect.
if KERNEL_KASAN
config KERNEL_KASAN_GENERIC
def_bool y