[PATCH iwl] eth: ice: don't dereference pointers from TP_printk()

[PATCH iwl] eth: ice: don't dereference pointers from TP_printk()

[Jakub Kicinski]

After forwarding net-next during the v7.3 merge window we started
seeing:

  TRACE EVENT ERROR: Event ice_tx_dim_work has double dereference in TP_printk: REC->q_vector->tx.tx_ring->q_index
  WARNING: kernel/trace/trace_events.c:420 at test_double_dereference.cold+0x39/0x4b

this is due to extra checks added in tracing subsystem in
commit b5cc230af5e5 ("tracing: Warn when an event dereferences a pointer in TP_printk()").

Printing happens long after the event was recorded, by which point
the pointers may be invalid (the ring or the dim instance).
Copy the eight scalars into the event instead.

Fixes: 3089cf6d3caa ("ice: add tracepoints")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: anthony.l.nguyen@intel.com
CC: przemyslaw.kitszel@intel.com
CC: jbrandeb@kernel.org
CC: benjamin.h.shelton@intel.com
---
 drivers/net/ethernet/intel/ice/ice_trace.h | 64 ++++++++++++++--------
 1 file changed, 42 insertions(+), 22 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_trace.h b/drivers/net/ethernet/intel/ice/ice_trace.h
index 4f35ef8d6b29..7568c917cdbe 100644
--- a/drivers/net/ethernet/intel/ice/ice_trace.h
+++ b/drivers/net/ethernet/intel/ice/ice_trace.h
@@ -63,23 +63,33 @@
 DECLARE_EVENT_CLASS(ice_rx_dim_template,
 		    TP_PROTO(struct ice_q_vector *q_vector, struct dim *dim),
 		    TP_ARGS(q_vector, dim),
-		    TP_STRUCT__entry(__field(struct ice_q_vector *, q_vector)
-				     __field(struct dim *, dim)
+		    TP_STRUCT__entry(__field(u16, q_index)
+				     __field(u8, state)
+				     __field(u8, profile_ix)
+				     __field(u8, tune_state)
+				     __field(u8, steps_right)
+				     __field(u8, steps_left)
+				     __field(u8, tired)
 				     __string(devname, q_vector->rx.rx_ring->netdev->name)),
 
-		    TP_fast_assign(__entry->q_vector = q_vector;
-				   __entry->dim = dim;
+		    TP_fast_assign(__entry->q_index = q_vector->rx.rx_ring->q_index;
+				   __entry->state = dim->state;
+				   __entry->profile_ix = dim->profile_ix;
+				   __entry->tune_state = dim->tune_state;
+				   __entry->steps_right = dim->steps_right;
+				   __entry->steps_left = dim->steps_left;
+				   __entry->tired = dim->tired;
 				   __assign_str(devname);),
 
 		    TP_printk("netdev: %s Rx-Q: %d dim-state: %d dim-profile: %d dim-tune: %d dim-st-right: %d dim-st-left: %d dim-tired: %d",
 			      __get_str(devname),
-			      __entry->q_vector->rx.rx_ring->q_index,
-			      __entry->dim->state,
-			      __entry->dim->profile_ix,
-			      __entry->dim->tune_state,
-			      __entry->dim->steps_right,
-			      __entry->dim->steps_left,
-			      __entry->dim->tired)
+			      __entry->q_index,
+			      __entry->state,
+			      __entry->profile_ix,
+			      __entry->tune_state,
+			      __entry->steps_right,
+			      __entry->steps_left,
+			      __entry->tired)
 );
 
 DEFINE_EVENT(ice_rx_dim_template, ice_rx_dim_work,
@@ -90,23 +100,33 @@ DEFINE_EVENT(ice_rx_dim_template, ice_rx_dim_work,
 DECLARE_EVENT_CLASS(ice_tx_dim_template,
 		    TP_PROTO(struct ice_q_vector *q_vector, struct dim *dim),
 		    TP_ARGS(q_vector, dim),
-		    TP_STRUCT__entry(__field(struct ice_q_vector *, q_vector)
-				     __field(struct dim *, dim)
+		    TP_STRUCT__entry(__field(u16, q_index)
+				     __field(u8, state)
+				     __field(u8, profile_ix)
+				     __field(u8, tune_state)
+				     __field(u8, steps_right)
+				     __field(u8, steps_left)
+				     __field(u8, tired)
 				     __string(devname, q_vector->tx.tx_ring->netdev->name)),
 
-		    TP_fast_assign(__entry->q_vector = q_vector;
-				   __entry->dim = dim;
+		    TP_fast_assign(__entry->q_index = q_vector->tx.tx_ring->q_index;
+				   __entry->state = dim->state;
+				   __entry->profile_ix = dim->profile_ix;
+				   __entry->tune_state = dim->tune_state;
+				   __entry->steps_right = dim->steps_right;
+				   __entry->steps_left = dim->steps_left;
+				   __entry->tired = dim->tired;
 				   __assign_str(devname);),
 
 		    TP_printk("netdev: %s Tx-Q: %d dim-state: %d dim-profile: %d dim-tune: %d dim-st-right: %d dim-st-left: %d dim-tired: %d",
 			      __get_str(devname),
-			      __entry->q_vector->tx.tx_ring->q_index,
-			      __entry->dim->state,
-			      __entry->dim->profile_ix,
-			      __entry->dim->tune_state,
-			      __entry->dim->steps_right,
-			      __entry->dim->steps_left,
-			      __entry->dim->tired)
+			      __entry->q_index,
+			      __entry->state,
+			      __entry->profile_ix,
+			      __entry->tune_state,
+			      __entry->steps_right,
+			      __entry->steps_left,
+			      __entry->tired)
 );
 
 DEFINE_EVENT(ice_tx_dim_template, ice_tx_dim_work,
-- 
2.55.0