This problem reported by Clement LE GOFFIC manifest when using CONFIG_KASAN_IN_VMALLOC and VMAP_STACK: https://lore.kernel.org/linux-arm-kernel/a1a1d062-f3a2-4d05-9836-3b098de9db6d@xxxxxxxxxxx/ After some analysis it seems we are missing to sync the VMALLOC shadow memory in top level PGD to all CPUs. Add some code to perform this sync, and the bug appears to go away. As suggested by Ard, also perform a dummy read from the shadow memory of the new VMAP_STACK in the low level assembly. Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> --- Linus Walleij (2): ARM: ioremap: Flush PGDs for VMALLOC shadow ARM: entry: Do a dummy read from VMAP shadow arch/arm/kernel/entry-armv.S | 8 ++++++++ arch/arm/mm/ioremap.c | 7 +++++++ 2 files changed, 15 insertions(+) --- base-commit: 9852d85ec9d492ebef56dc5f229416c925758edc change-id: 20241015-arm-kasan-vmalloc-crash-fcbd51416457 Best regards, -- Linus Walleij <linus.walleij@xxxxxxxxxx>
