6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Linus Walleij linus.walleij@linaro.org
commit 44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 upstream.
When switching task, in addition to a dummy read from the new VMAP stack, also do a dummy read from the VMAP stack's corresponding KASAN shadow memory to sync things up in the new MM context.
Cc: stable@vger.kernel.org Fixes: a1c510d0adc6 ("ARM: implement support for vmap'ed stacks") Link: https://lore.kernel.org/linux-arm-kernel/a1a1d062-f3a2-4d05-9836-3b098de9db6... Reported-by: Clement LE GOFFIC clement.legoffic@foss.st.com Suggested-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Russell King (Oracle) rmk+kernel@armlinux.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm/kernel/entry-armv.S | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -25,6 +25,7 @@ #include <asm/tls.h> #include <asm/system_info.h> #include <asm/uaccess-asm.h> +#include <asm/kasan_def.h>
#include "entry-header.S" #include <asm/probes.h> @@ -555,6 +556,13 @@ ENTRY(__switch_to) @ entries covering the vmalloc region. @ ldr r2, [ip] +#ifdef CONFIG_KASAN_VMALLOC + @ Also dummy read from the KASAN shadow memory for the new stack if we + @ are using KASAN + mov_l r2, KASAN_SHADOW_OFFSET + add r2, r2, ip, lsr #KASAN_SHADOW_SCALE_SHIFT + ldr r2, [r2] +#endif #endif
@ When CONFIG_THREAD_INFO_IN_TASK=n, the update of SP itself is what