VIMAGE + kldload wlan + kldload wtap panic

[Adrian Chadd]

Hi,

The trouble here is that net80211 has quite a few other contexts that
things are called from:

* driver taskqueue;
* net80211 taskqueue;
* driver callouts;
* net80211 callouts;
* ioctls via net80211.

That's in parallel with frame tx/rx and device ioctls.

I don't personally have the time to go through net80211 and driver(s)
at the moment to figure out what's going on. Since ath(4) does a bunch
of frame processing in taskqueue context (and I'm trying to eliminate
frame processing in _callout_ context, ew..) things can potentially
get a bit hairy.


Adrian


On 6 March 2012 11:59, Marko Zec <zec at fer.hr> wrote:
> On Tuesday 06 March 2012 20:49:38 Monthadar Al Jaberi wrote:
>> I added VNET_DEBUG and noticed this warning (original scan_task code):
>>
>> CURVNET_SET() recursion in sosend() line 1350, prev in kern_kldload()
>>     0xfffffe0002202c40 -> 0xfffffe0002202c40
>> KDB: stack backtrace:
>> db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
>> kdb_backtrace() at kdb_backtrace+0x37
>> sosend() at sosend+0xbd
>> clnt_vc_call() at clnt_vc_call+0x3e6
>> clnt_reconnect_call() at clnt_reconnect_call+0xf5
>> newnfs_request() at newnfs_request+0x9fb
>> nfscl_request() at nfscl_request+0x72
>> nfsrpc_lookup() at nfsrpc_lookup+0x1be
>> nfs_lookup() at nfs_lookup+0x297
>> VOP_LOOKUP_APV() at VOP_LOOKUP_APV+0x95
>> lookup() at lookup+0x3b8
>> namei() at namei+0x484
>> vn_open_cred() at vn_open_cred+0x1e2
>> link_elf_load_file() at link_elf_load_file+0xb3
>> linker_load_module() at linker_load_module+0x794
>> kern_kldload() at kern_kldload+0x145
>> sys_kldload() at sys_kldload+0x84
>> amd64_syscall() at amd64_syscall+0x39e
>> Xfast_syscall() at Xfast_syscall+0xf7
>
> You can safely ignore those.  Recursing on curvnet is harmless, but in certain
> cases can't be avoided.
>
> When injecting new CURVNET_SET() / CURVNET_RESTORE() points in the existing
> code, those warnings are here to help us becoming aware that we are setting
> curvnet in a function which was invoked with an already valid curvnet
> context.
>
> Marko