parse-events: Fix segfault of print array processing

The reading of an element in an array assumed the arg was a field
type event though the arg could have been of a dynamic array type.
This caused a Seg fault when processing dynamic arrays.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/parse-events.c b/parse-events.c
index 0f7b1f1..91d6788 100644
--- a/parse-events.c
+++ b/parse-events.c
@@ -2839,6 +2839,7 @@ eval_num_arg(void *data, int size, struct event_format *event, struct print_arg
         struct print_arg *typearg = NULL;
         struct print_arg *larg;
         unsigned long offset;
+        unsigned int field_size;
 
         switch (arg->type) {
         case PRINT_NULL:
@@ -2885,6 +2886,9 @@ eval_num_arg(void *data, int size, struct event_format *event, struct print_arg
                                 larg = larg->typecast.item;
                         }
 
+                        /* Default to long size */
+                        field_size = pevent->long_size;
+
                         switch (larg->type) {
                         case PRINT_DYNAMIC_ARRAY:
                                 offset = pevent_read_number(pevent,
@@ -2905,6 +2909,7 @@ eval_num_arg(void *data, int size, struct event_format *event, struct print_arg
                                         if (!larg->field.field)
                                                 die("field %s not found", larg->field.name);
                                 }
+                                field_size = larg->field.field->elementsize;
                                 offset = larg->field.field->offset +
                                         right * larg->field.field->elementsize;
                                 break;
@@ -2912,7 +2917,7 @@ eval_num_arg(void *data, int size, struct event_format *event, struct print_arg
                                 goto default_op; /* oops, all bets off */
                         }
                         val = pevent_read_number(pevent,
-                                                 data + offset, larg->field.field->elementsize);
+                                                 data + offset, field_size);
                         if (typearg)
                                 val = eval_type(val, typearg, 1);
                         break;