diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/Makefile | 10 | ||||
| -rw-r--r-- | arch/x86/include/asm/kmsan.h | 17 |
2 files changed, 21 insertions, 6 deletions
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 1a068de12a56..2264db14a25d 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -112,13 +112,13 @@ ifeq ($(CONFIG_X86_32),y) # temporary until string.h is fixed KBUILD_CFLAGS += -ffreestanding - ifeq ($(CONFIG_STACKPROTECTOR),y) - ifeq ($(CONFIG_SMP),y) + ifeq ($(CONFIG_STACKPROTECTOR),y) + ifeq ($(CONFIG_SMP),y) KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard - else + else KBUILD_CFLAGS += -mstack-protector-guard=global - endif - endif + endif + endif else BITS := 64 UTS_MACHINE := x86_64 diff --git a/arch/x86/include/asm/kmsan.h b/arch/x86/include/asm/kmsan.h index 8fa6ac0e2d76..d91b37f5b4bb 100644 --- a/arch/x86/include/asm/kmsan.h +++ b/arch/x86/include/asm/kmsan.h @@ -64,6 +64,7 @@ static inline bool kmsan_virt_addr_valid(void *addr) { unsigned long x = (unsigned long)addr; unsigned long y = x - __START_KERNEL_map; + bool ret; /* use the carry flag to determine if x was < __START_KERNEL_map */ if (unlikely(x > y)) { @@ -79,7 +80,21 @@ static inline bool kmsan_virt_addr_valid(void *addr) return false; } - return pfn_valid(x >> PAGE_SHIFT); + /* + * pfn_valid() relies on RCU, and may call into the scheduler on exiting + * the critical section. However, this would result in recursion with + * KMSAN. Therefore, disable preemption here, and re-enable preemption + * below while suppressing reschedules to avoid recursion. + * + * Note, this sacrifices occasionally breaking scheduling guarantees. + * Although, a kernel compiled with KMSAN has already given up on any + * performance guarantees due to being heavily instrumented. + */ + preempt_disable(); + ret = pfn_valid(x >> PAGE_SHIFT); + preempt_enable_no_resched(); + + return ret; } #endif /* !MODULE */ |