Messages in this thread Patch in this message | | | Subject | [PATCH -tip v2 2/3] [BUGFIX] kprobes/x86: Prohibit probing on debug_stack_* | From | Masami Hiramatsu <> | Date | Fri, 01 Nov 2013 11:25:34 +0000 |
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Prohibit probing on debug_stack_reset and debug_stack_set_zero. Since the both functions are called from TRACE_IRQS_ON/OFF_DEBUG macros which run in int3 ist entry, probing it may cause a soft lockup.
This happens when the kernel built with CONFIG_DYNAMIC_FTRACE=y and CONFIG_TRACE_IRQFLAGS=y.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Borislav Petkov <bp@suse.de> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Seiji Aguchi <seiji.aguchi@hds.com> --- arch/x86/kernel/cpu/common.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 1789b06..928a4fd 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1157,7 +1157,7 @@ DEFINE_PER_CPU(struct orig_ist, orig_ist); static DEFINE_PER_CPU(unsigned long, debug_stack_addr); DEFINE_PER_CPU(int, debug_stack_usage); -int is_debug_stack(unsigned long addr) +int nokprobe is_debug_stack(unsigned long addr) { return __get_cpu_var(debug_stack_usage) || (addr <= __get_cpu_var(debug_stack_addr) && @@ -1166,13 +1166,13 @@ int is_debug_stack(unsigned long addr) DEFINE_PER_CPU(u32, debug_idt_ctr); -void debug_stack_set_zero(void) +void nokprobe debug_stack_set_zero(void) { this_cpu_inc(debug_idt_ctr); load_current_idt(); } -void debug_stack_reset(void) +void nokprobe debug_stack_reset(void) { if (WARN_ON(!this_cpu_read(debug_idt_ctr))) return;
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