From 1ee4e35076e36724a62ba2fa29b722fb53eb68f2 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Fri, 16 Dec 2022 21:59:30 +1000 Subject: powerpc: Skip stack validation checking alternate stacks if they are not allocated 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 Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221216115930.2667772-5-npiggin@gmail.com --- arch/powerpc/kernel/process.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index effe9697905d..4b29ac5ddac6 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2117,6 +2117,9 @@ 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; @@ -2138,6 +2141,14 @@ 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; -- cgit