[PATCH 2/3] x86/hw_breakpoint: Add stack_canary to hw_breakpoints denylist

[Lai Jiangshan]

From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>

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

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
---
 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