Date: Tue, 6 Mar 2012 21:51:10 +0100 From: Marko Zec <zec@fer.hr> To: freebsd-virtualization@freebsd.org Cc: Adrian Chadd <adrian.chadd@gmail.com> Subject: Re: VIMAGE + kldload wlan + kldload wtap panic Message-ID: <201203062151.10569.zec@fer.hr> In-Reply-To: <CA%2BsBSo%2BzG%2BF1c3xhtTiAOagyseGP=17Vd4zLGYaTj-pqgoXAtA@mail.gmail.com> References: <CA%2BsBSo%2Bt=p0HLbyOH87DOJWWYn%2Be%2Bok7cwRiL1c1=gCw5=KTqg@mail.gmail.com> <201203062122.15426.zec@fer.hr> <CA%2BsBSo%2BzG%2BF1c3xhtTiAOagyseGP=17Vd4zLGYaTj-pqgoXAtA@mail.gmail.com>
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On Tuesday 06 March 2012 21:29:32 Monthadar Al Jaberi wrote:
> On Tue, Mar 6, 2012 at 9:22 PM, Marko Zec <zec@fer.hr> wrote:
> > On Tuesday 06 March 2012 21:13:00 Monthadar Al Jaberi wrote:
> >> I am confused so whats the difference between having wlan in kernel
> >> config or not? Cuase that seems the reason why we panic... linker
> >> problems?
> >
> > Its not impossible.
> >
> > Have you tried to do CURVNET_SET(ss->ss_vap->iv_ifp->if_vnet) on entry =
to
> > scan_task() as I suggested earlier in this thread?
>
> this is the code I added:
> diff --git a/sys/net80211/ieee80211_scan.c b/sys/net80211/ieee80211_scan.c
> index 5c1e3d9..bd20653 100644
> --- a/sys/net80211/ieee80211_scan.c
> +++ b/sys/net80211/ieee80211_scan.c
> @@ -850,6 +850,7 @@ scan_task(void *arg, int pending)
> int scandone =3D 0;
>
> IEEE80211_LOCK(ic);
> + CURVNET_SET((struct ieee80211_scan_state *)
> ss->ss_vap->iv_ifp->if_curvnet);
The explicit cast is redundant here, I only used it earlier to clarify the=
=20
type of variable ss...
Anyhow, by looking again at the backtrace you posted at the begining of thi=
s=20
thread, it's apparent that the code calls into rt_dispatch() and fails at=20
line 1494:
#ifdef VIMAGE
if (V_loif)
m->m_pkthdr.rcvif =3D V_loif;
...
because curvnet is not set, or is pointing somewhere where it shouldn't.
Can you post the output of show pcpu and show vnets from ddb> prompt when y=
ou=20
get the panic?
Have you actually booted a freshly built kernel? I pretty sure it's=20
impossible for CURVNET_SET() to succeed with a NULL or an incorrect vnet=20
pointer as an argument when the kernel is buitl with VNET_DEBUG, so I don't=
=20
see how it may be possible for a patched scan_task() to call into=20
rt_dispatch() with wrong curvnet.
Cheers,
Marko
> if (vap =3D=3D NULL || (ic->ic_flags & IEEE80211_F_SCAN) =3D=3D 0=
||
> (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
> /* Cancelled before we started */
> @@ -1004,6 +1005,7 @@ scan_task(void *arg, int pending)
> ss->ss_ops->scan_restart(ss, vap); /* XXX? */
> ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
> IEEE80211_UNLOCK(ic);
> + CURVNET_RESTORE();
> return;
> }
>
> @@ -1043,6 +1045,7 @@ done:
> SCAN_PRIVATE(ss)->ss_iflags &=3D ~(ISCAN_CANCEL|ISCAN_ABORT);
> ss->ss_flags &=3D ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
> IEEE80211_UNLOCK(ic);
> + CURVNET_RESTORE();
> #undef ISCAN_REP
> }
>
> same panic...
>
> > Cheers,
> >
> > Marko
> >
> >> On Tue, Mar 6, 2012 at 9:06 PM, Adrian Chadd <adrian.chadd@gmail.com>=
=20
wrote:
> >> > 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 bun=
ch
> >> > 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@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. =A0Recursing on curvnet is harmless, b=
ut
> >> >> 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 th=
at
> >> >> we are setting curvnet in a function which was invoked with an
> >> >> already valid curvnet context.
> >> >>
> >> >> Marko
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