Re: [kbuild-all] Re: kernel/trace/trace_events_synth.c:436:68: sparse: sparse: incorrect type in argument 2 (different address spaces)

[Chen, Rong A]

On 10/19/2022 9:34 PM, Steven Rostedt wrote:
> On Wed, 19 Oct 2022 11:43:54 +0800
> kernel test robot <lkp@xxxxxxxxx> wrote:
>
> > sparse warnings: (new ones prefixed by >>)
> > > > kernel/trace/trace_events_synth.c:436:68: sparse: sparse: incorrect type in argument 2 (different address spaces) @@     expected void const [noderef] __user *unsafe_addr @@     got char *str_val @@
> >     kernel/trace/trace_events_synth.c:436:68: sparse:     expected void const [noderef] __user *unsafe_addr
> >     kernel/trace/trace_events_synth.c:436:68: sparse:     got char *str_val
> >
> > vim +436 kernel/trace/trace_events_synth.c
> >
> >     404	
> >     405	static unsigned int trace_string(struct synth_trace_event *entry,
> >     406					 struct synth_event *event,
> >     407					 char *str_val,
> >     408					 bool is_dynamic,
> >     409					 unsigned int data_size,
> >     410					 unsigned int *n_u64)
> >     411	{
> >     412		unsigned int len = 0;
> >     413		char *str_field;
> >     414		int ret;
> >     415	
> >     416		if (is_dynamic) {
> >     417			u32 data_offset;
> >     418	
> >     419			data_offset = offsetof(typeof(*entry), fields);
> >     420			data_offset += event->n_u64 * sizeof(u64);
> >     421			data_offset += data_size;
> >     422	
> >     423			len = kern_fetch_store_strlen((unsigned long)str_val);
> >     424	
> >     425			data_offset |= len << 16;
> >     426			*(u32 *)&entry->fields[*n_u64] = data_offset;
> >     427	
> >     428			ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
> >     429	
> >     430			(*n_u64)++;
> >     431		} else {
> >     432			str_field = (char *)&entry->fields[*n_u64];
> >     433	
> >     434	#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> >     435			if ((unsigned long)str_val < TASK_SIZE)
> >   > 436				ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX);
> >     437			else
> >     438	#endif
> >     439				ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
> >     440	
>
>
> Does this fix it?

Hi Steve,

I tried the below patch, it can fix the issue.

Best Regards,
Rong Chen

> -- Steve
>
> diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
> index e310052dc83c..2562d7522999 100644
> --- a/kernel/trace/trace_events_synth.c
> +++ b/kernel/trace/trace_events_synth.c
> @@ -433,7 +433,8 @@ static unsigned int trace_string(struct synth_trace_event *entry,
>   
>   #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>   		if ((unsigned long)str_val < TASK_SIZE)
> -			ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX);
> +			ret = strncpy_from_user_nofault(str_field,
> +				(__force const void __user *)str_val, STR_VAR_LEN_MAX);
>   		else
>   #endif
>   			ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
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