Identify cause of ieee80211_get_counter

[Farhan Khan]

Hi everyone.

I am working through the driver, and running into some 
ieee80211_get_counter()'s. Per sys/net80211/ieee80211.c, the comment 
says "Add underlying device errors to vap errors", which implies that it 
will only trigger when an error occurs.

Is there a way to identify what the cause of the function call is? I ran 
dtrace against "fbt:kernel:ieee80211_get_counter:entry" with a stack() 
trace as follows:

CPU     ID                    FUNCTION:NAME
   3  17127      ieee80211_get_counter:entry
               kernel`if_data_copy+0xa1
               kernel`sysctl_rtsock+0x2b6
               kernel`sysctl_root_handler_locked+0x7b
               kernel`sysctl_root+0x1c6
               kernel`userland_sysctl+0x148
               kernel`sys___sysctl+0x5f
               kernel`amd64_syscall+0x79b
               kernel`0xffffffff80ed07bb

Is there an efficient way to identify what the cause of the error is?

Thank you,

--
Farhan Khan
PGP Fingerprint: B28D 2726 E2BC A97E 3854 5ABE 9A9F 00BC D525 16EE