From:   Lai Jiangshan <jiangshanlai@gmail.com>
To:     linux-kernel@vger.kernel.org
Cc:     x86@kernel.org, Lai Jiangshan <laijs@linux.alibaba.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH 2/3] x86/hw_breakpoint: Add stack_canary to hw_breakpoints denylist
Date:   Mon, 13 Dec 2021 12:22:14 +0800
Message-Id: <20211213042215.3096-3-jiangshanlai@gmail.com>
In-Reply-To: <20211213042215.3096-1-jiangshanlai@gmail.com>
References: <20211213042215.3096-1-jiangshanlai@gmail.com>
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From: Lai Jiangshan <laijs@linux.alibaba.com>

When stack-protector is enabled, entry functions may access
to the stack_canary.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
 arch/x86/kernel/hw_breakpoint.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index 668a4a6533d9..b2b64afdf9c0 100644
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -315,6 +315,14 @@ static inline bool within_cpu_entry(unsigned long addr, unsigned long end)
 		if (within_area(addr, end, (unsigned long)&per_cpu(cpu_dr7, cpu),
 				sizeof(cpu_dr7)))
 			return true;
+
+		/*
+		 * When stack-protector is enabled, entry functions may access
+		 * to the stack_canary.
+		 */
+		if (within_area(addr, end, (unsigned long)&per_cpu(fixed_percpu_data, cpu),
+				sizeof(struct fixed_percpu_data)))
+			return true;
 	}
 
 	return false;
-- 
2.19.1.6.gb485710b