Re: [PATCH -next] x86: Prevent KASAN false positive warnings in __show_regs()

[Tengda Wu]

On 2025/8/29 3:16, Josh Poimboeuf wrote:
> On Thu, Aug 28, 2025 at 08:06:17PM +0800, Tengda Wu wrote:
>> +++ b/arch/x86/kernel/dumpstack.c
>> @@ -189,9 +189,15 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
>>         unsigned long visit_mask = 0;
>>         int graph_idx = 0;
>>         bool partial = false;
>> +       bool kasan_disabled = false;
>>  
>>         printk("%sCall Trace:\n", log_lvl);
>>  
>> +       if (task != current) {
>> +               kasan_disable_current();
>> +               kasan_disabled = true;
>> +       }
> 
> Looks reasonable to me, though note that some callers pass a NULL @task
> to indicate 'current'.
> 
> (No idea why, that subtlety should probably be removed...)
> 
> So this might need to be
> 
> 	if (task && task != current) {
> 		...
> 

Dave mentioned that there's an object_is_on_stack available, which is
essentially on_current_stack. I will try using it and send out v2.

Thanks,
Tengda