path: root/arch
diff options
authorLai Jiangshan <laijs@linux.alibaba.com>2020-05-29 23:27:31 +0200
committerThomas Gleixner <tglx@linutronix.de>2020-06-11 15:15:21 +0200
commitf9fe0b89f05441c6e4034e024c2c75a0d93024c1 (patch)
treed14ad2e4e30c00b46a2c1c51aaa99e9d587c4bc4 /arch
parent97417cb9ad4ed052d7a4c5c0d75db1ff1b0981fb (diff)
x86/hw_breakpoint: Prevent data breakpoints on per_cpu cpu_tss_rw
cpu_tss_rw is not directly referenced by hardware, but cpu_tss_rw is accessed in CPU entry code, especially when #DB shifts its stacks. If a data breakpoint would be set on cpu_tss_rw.x86_tss.ist[IST_INDEX_DB], it would cause recursive #DB ending up in a double fault. Add it to the list of protected items. Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200526014221.2119-4-laijs@linux.alibaba.com Link: https://lkml.kernel.org/r/20200529213320.897976479@infradead.org
Diffstat (limited to 'arch')
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index f859095c1b6c..f311bbfda1ba 100644
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -255,6 +255,15 @@ static inline bool within_cpu_entry(unsigned long addr, unsigned long end)
if (within_area(addr, end, (unsigned long)get_cpu_gdt_rw(cpu),
return true;
+ /*
+ * cpu_tss_rw is not directly referenced by hardware, but
+ * cpu_tss_rw is also used in CPU entry code,
+ */
+ if (within_area(addr, end,
+ (unsigned long)&per_cpu(cpu_tss_rw, cpu),
+ sizeof(struct tss_struct)))
+ return true;
return false;

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