bcm43xx for d80211 softirq loop

[Johannes Berg <johannes@sipsolutions.net>]

[23750.726463] NETDEV WATCHDOG: wmaster0: transmit timed out
[23750.726482] wmaster0: resetting interface.
[23750.726490] bcm43xx_d80211: Controller RESET (IEEE reset) ...
[23750.753458] bcm43xx_d80211: select_wireless_core: cleanup
[23750.753477] bcm43xx_d80211: Radio turned off
[23750.753538] bcm43xx_d80211: DMA 0x0200 (RX) max used slots: 1/64
[23750.755208] bcm43xx_d80211: DMA 0x0260 (TX) max used slots: 0/512
[23750.755601] bcm43xx_d80211: DMA 0x0240 (TX) max used slots: 0/512
[23750.755992] bcm43xx_d80211: DMA 0x0220 (TX) max used slots: 0/512
[23750.756383] bcm43xx_d80211: DMA 0x0200 (TX) max used slots: 0/512
[23750.957250] bcm43xx_d80211: Radio turned on
[23751.129344] bcm43xx_d80211: Chip initialized
[23751.137239] bcm43xx_d80211: DMA initialized
[23751.137503] bcm43xx_d80211: Keys cleared
[23751.153242] bcm43xx_d80211: Selected 802.11 core (phytype 2)
[23751.153263] bcm43xx_d80211: Controller restarted


after this, ksoftirq started running wild...

Since oprofile doesn't show any function ever called for a tasklet, I 
started to investigate but couldn't find what was up. Then I removed the 
bcm43xx_dscape module and the kernel blew up right away.

Then I patched the kernel with a runaway tasklet patch (see mail on 
lkml) and got this (yeah, previous iteration of the patch where I forgot 
a "\n"):

[15214.574151] NETDEV WATCHDOG: wmaster0: transmit timed out
[15214.574166] wmaster0: resetting interface.
[15214.574174] bcm43xx_d80211: Controller RESET (IEEE reset) ...
[15214.591194] bcm43xx_d80211: select_wireless_core: cleanup
[15214.591209] bcm43xx_d80211: Radio turned off
[15214.591270] bcm43xx_d80211: DMA 0x0200 (RX) max used slots: 1/64
[15214.592901] bcm43xx_d80211: DMA 0x0260 (TX) max used slots: 0/512
[15214.593294] bcm43xx_d80211: DMA 0x0240 (TX) max used slots: 0/512
[15214.593685] bcm43xx_d80211: DMA 0x0220 (TX) max used slots: 0/512
[15214.594075] bcm43xx_d80211: DMA 0x0200 (TX) max used slots: 0/512
[15214.773961] bcm43xx_d80211: Radio turned on
[15214.945901] bcm43xx_d80211: Chip initialized
[15214.953815] bcm43xx_d80211: DMA initialized
[15214.954078] bcm43xx_d80211: Keys cleared
[15214.969864] bcm43xx_d80211: Selected 802.11 core (phytype 2)
[15214.969889] bcm43xx_d80211: Controller restarted
[15215.019746] tasklet 
drivers/net/wireless/d80211/bcm43xx/bcm43xx_main.c:4376 is scheduled but 
hasn't been enabled for too long!
<6>NETDEV WATCHDOG: wmaster0: transmit timed out
[15769.964164] wmaster0: resetting interface.
[15769.964175] bcm43xx_d80211: Controller RESET (IEEE reset) ...
[15769.995145] bcm43xx_d80211: select_wireless_core: cleanup
[15769.995166] bcm43xx_d80211: Radio turned off
[15769.995249] bcm43xx_d80211: DMA 0x0200 (RX) max used slots: 0/64
[15769.997222] bcm43xx_d80211: DMA 0x0260 (TX) max used slots: 0/512
[15769.997615] bcm43xx_d80211: DMA 0x0240 (TX) max used slots: 0/512
[15769.998006] bcm43xx_d80211: DMA 0x0220 (TX) max used slots: 0/512
[15769.998397] bcm43xx_d80211: DMA 0x0200 (TX) max used slots: 0/512
[15770.162013] bcm43xx_d80211: IRQ_READY timeout
[15770.162059] bcm43xx_d80211: core_up for active 802.11 core failed (-19)
[15770.162076] bcm43xx_d80211: Controller restart failed


Hence, I'm able to point to bcm43xx now ;) Sorry I can't give a better 
indication of what's up, I can try a different patch if you can come up 
with a good way of debugging it. This usually seems to happen here after 
an hour or two of not using the interface at all.

johannes