diff options
| author | Lai Jiangshan | 2020-05-29 23:27:32 +0200 |
|---|---|---|
| committer | Thomas Gleixner | 2020-06-11 15:15:21 +0200 |
| commit | fdef24dfccb7be06e6ebe11d6c6c56987421870f (patch) | |
| tree | 1f3f6923203775c98c9c1913676e0f8f4afb5d89 | |
| parent | f9fe0b89f05441c6e4034e024c2c75a0d93024c1 (diff) | |
x86/hw_breakpoint: Prevent data breakpoints on user_pcid_flush_mask
The per-CPU user_pcid_flush_mask is used in the low level entry code. A
data breakpoint can cause #DB recursion.
Protect the full cpu_tlbstate structure for simplicity.
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/20200526014221.2119-5-laijs@linux.alibaba.com
Link: https://lkml.kernel.org/r/20200529213320.955117574@infradead.org
| -rw-r--r-- | arch/x86/kernel/hw_breakpoint.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index f311bbfda1ba..fc1743a2b0e9 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -33,6 +33,7 @@ #include <asm/debugreg.h> #include <asm/user.h> #include <asm/desc.h> +#include <asm/tlbflush.h> /* Per cpu debug control register value */ DEFINE_PER_CPU(unsigned long, cpu_dr7); @@ -264,6 +265,16 @@ static inline bool within_cpu_entry(unsigned long addr, unsigned long end) (unsigned long)&per_cpu(cpu_tss_rw, cpu), sizeof(struct tss_struct))) return true; + + /* + * cpu_tlbstate.user_pcid_flush_mask is used for CPU entry. + * If a data breakpoint on it, it will cause an unwanted #DB. + * Protect the full cpu_tlbstate structure to be sure. + */ + if (within_area(addr, end, + (unsigned long)&per_cpu(cpu_tlbstate, cpu), + sizeof(struct tlb_state))) + return true; } return false; |