Stack validation in early boot can just bail out of checking alternate
stacks if they are not validated yet. Checking against a NULL stack
could cause NULLish pointer values to be considered valid.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/kernel/process.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index edb46d0806ef..95d605bdff85 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -2118,6 +2118,9 @@ static inline int valid_irq_stack(unsigned long sp,
struct task_struct *p,
unsigned long stack_page;
unsigned long cpu = task_cpu(p);
+ if (!hardirq_ctx[cpu] || !softirq_ctx[cpu])
+ return 0;
+
stack_page = (unsigned long)hardirq_ctx[cpu];
if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
@@ -2139,6 +2142,14 @@ static inline int valid_emergency_stack(unsigned long
sp, struct task_struct *p,
if (!paca_ptrs)
return 0;
+ if (!paca_ptrs[cpu]->emergency_sp)
+ return 0;
+
+# ifdef CONFIG_PPC_BOOK3S_64
+ if (!paca_ptrs[cpu]->nmi_emergency_sp ||
!paca_ptrs[cpu]->mc_emergency_sp)
+ return 0;
+#endif
+
stack_page = (unsigned long)paca_ptrs[cpu]->emergency_sp - THREAD_SIZE;
if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
--
2.37.2
