Date: Thu, 14 May 2009 15:02:03 -0400 From: Alexander Sack <pisymbol@gmail.com> To: freebsd-current@freebsd.org Subject: Broadcom bge(4) panics while shutting down Message-ID: <3c0b01820905141202w113966dp4bfbab73d84d585@mail.gmail.com>
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Hello:
Under heavy traffic (100% utilization GIGE on a 2 port BGE card)
running BGE CURRENT driver I see panics on shutdown. The reason is
because bge_rxeof() while processing its RX ring of BD's drops the
softc lock when it hands it off to its input function. If bge_stop()
is waiting for it, it will then proceed to acquire lock and then
quiesce the hardware (reseting the card, clearing out BDs etc.). Once
bge_stop() releases the softc lock, then bge_rxeof() under an
interrupt context (no polling here) will reacquire and continue to
process the ring which is a bad idea. It should check to see if the
card is still running before continuing processing BDs (i.e. once
IF_DRV_RUNNING has been reset by bge_stop(), bge_rxeof() is done, bail
out).
Here is my first go around with this patch:
-- if_bge.c.CURRENT 2009-05-14 14:39:39.000000000 -0400
+++ if_bge.c 2009-05-14 14:39:24.000000000 -0400
@@ -3081,6 +3081,10 @@
uint16_t vlan_tag = 0;
int have_tag = 0;
+ if (!(ifp->if_drv_flags & IFF_DRV_RUNNING)) {
+ return;
+ }
+
#ifdef DEVICE_POLLING
if (ifp->if_capenable & IFCAP_POLLING) {
if (sc->rxcycles <= 0)
This prevents any panics during shutdown under heavy load and AS IT
TURNS out (I feel stupid for not looking) that em(4) already had this
check in its em_rxeof() function (right at the top of the loop). I'm
more than happy changing it to the em style but above seems reasonable
to me though I have to verify there isn't anything missing off the
loop from a hardware standpoint (I don't think so because bge_stop()
did all the dirty work so I believe touching any registers after that
from bge_rxeof() is a bad idea).
Preliminary testing shows no more panics start and stopping ports
under heavy load (panics were almost immediate otherwise).
Thoughts?
-aps
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