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[115.64.236.36]) by smtp.gmail.com with ESMTPSA id g22-20020a625216000000b0057ef155103asm1289438pfb.155.2022.12.16.03.59.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Dec 2022 03:59:45 -0800 (PST) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH 4/4] powerpc: Skip stack validation checking alternate stacks if they are not allocated Date: Fri, 16 Dec 2022 21:59:30 +1000 Message-Id: <20221216115930.2667772-5-npiggin@gmail.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20221216115930.2667772-1-npiggin@gmail.com> References: <20221216115930.2667772-1-npiggin@gmail.com> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 --- 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;