Re: [PATCH] [PATCH] cxl: trace: Fix macro safety in CXL_EVT_TP_fast_assign

[shaikh kamaluddin <shaikhkamal2012@gmail.com>]

On 4/24/25 03:22, Ira Weiny wrote:
> shaikh.kamal wrote:
>> Fix checkpatch.pl detected error
>> The CXL_EVT_TP_fast_assign macro assigns multiple fields, but does not
>> wrap the body in a `do { ... } while (0)` block. This can lead to
>> unexpected behavior when used in conditional branches.
>>
>> Add checks to ensure cxlmd is valid before accessing its fields.
>>
>> Signed-off-by: shaikh.kamal <shaikhkamal2012@gmail.com>
> Nak
>
> This is not a normal macro.  checkpatch.pl does not apply in this case.
> Also checking cxlmd here is not necessary.  The callers of the tracepoint
> know very well that it needs to be valid.
>
> Ira
> Thanks for your comments.
>> ---
>>   drivers/cxl/core/trace.h | 30 ++++++++++++++++++------------
>>   1 file changed, 18 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
>> index 25ebfbc1616c..a1a1014ee1fe 100644
>> --- a/drivers/cxl/core/trace.h
>> +++ b/drivers/cxl/core/trace.h
>> @@ -249,18 +249,24 @@ TRACE_EVENT(cxl_overflow,
>>   	__field(u8, hdr_maint_op_class)				\
>>   	__field(u8, hdr_maint_op_sub_class)
>>   
>> -#define CXL_EVT_TP_fast_assign(cxlmd, l, hdr)					\
>> -	__assign_str(memdev);				\
>> -	__assign_str(host);			\
>> -	__entry->log = (l);							\
>> -	__entry->serial = (cxlmd)->cxlds->serial;				\
>> -	__entry->hdr_length = (hdr).length;					\
>> -	__entry->hdr_flags = get_unaligned_le24((hdr).flags);			\
>> -	__entry->hdr_handle = le16_to_cpu((hdr).handle);			\
>> -	__entry->hdr_related_handle = le16_to_cpu((hdr).related_handle);	\
>> -	__entry->hdr_timestamp = le64_to_cpu((hdr).timestamp);			\
>> -	__entry->hdr_maint_op_class = (hdr).maint_op_class;			\
>> -	__entry->hdr_maint_op_sub_class = (hdr).maint_op_sub_class
>> +#define CXL_EVT_TP_fast_assign(cxlmd, l, hdr) \
>> +	do { \
>> +		if (!(cxlmd)) { \
>> +			pr_err("Invalid arguments to CXL_EVT_TP_fast_assign\n"); \
>> +			break; \
>> +		} \
>> +		__assign_str(memdev); \
>> +		__assign_str(host); \
>> +		__entry->log = (l); \
>> +		__entry->serial = (cxlmd)->cxlds->serial; \
>> +		__entry->hdr_length = (hdr).length; \
>> +		__entry->hdr_flags = get_unaligned_le24((hdr).flags); \
>> +		__entry->hdr_handle = le16_to_cpu((hdr).handle); \
>> +		__entry->hdr_related_handle = le16_to_cpu((hdr).related_handle); \
>> +		__entry->hdr_timestamp = le64_to_cpu((hdr).timestamp); \
>> +		__entry->hdr_maint_op_class = (hdr).maint_op_class; \
>> +		__entry->hdr_maint_op_sub_class = (hdr).maint_op_sub_class; \
>> +	} while (0)
>>   
>>   #define CXL_EVT_TP_printk(fmt, ...) \
>>   	TP_printk("memdev=%s host=%s serial=%lld log=%s : time=%llu uuid=%pUb "	\
>> -- 
>> 2.43.0
>>
>