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

[shaikh kamaluddin]

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@xxxxxxxxx>
> 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