arm64: Mark __stack_chk_guard as __ro_after_init

[ Upstream commit 9fcb2e93f41c07a400885325e7dbdfceba6efaec ]

__stack_chk_guard is setup once while init stage and never changed
after that.

Although the modification of this variable at runtime will usually
cause the kernel to crash (so does the attacker), it should be marked
as __ro_after_init, and it should not affect performance if it is
placed in the ro_after_init section.

Signed-off-by: Dan Li <ashimida@linux.alibaba.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/1631612642-102881-1-git-send-email-ashimida@linux.alibaba.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index d6a49bb07a5f5fec853c41d4077a2dd3cb1401e3..1945b8096a06a0b898b2d761ea7068bda9dbbb44 100644 (file)
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -61,7 +61,7 @@
 
 #ifdef CONFIG_STACKPROTECTOR
 #include <linux/stackprotector.h>
-unsigned long __stack_chk_guard __read_mostly;
+unsigned long __stack_chk_guard __ro_after_init;
 EXPORT_SYMBOL(__stack_chk_guard);
 #endif