Firmware panic, 'Unable to remove station entry...'

[Jason Conti]

On Thu, Apr 24, 2014 at 4:16 PM, Oleksij Rempel <linux at rempel-privat.de> wrote:
> Looks like ot filed to allocate tx buffer:
>
> static struct ath_tx_buf* ath_tx_buf_alloc(struct ath_softc_tgt *sc)
> {
>         struct ath_tx_buf *bf = NULL;
>
>         bf = asf_tailq_first(&sc->sc_txbuf);
>         if (bf !=  NULL) {
>                 adf_os_mem_set(&bf->bf_state, 0, sizeof(struct
> ath_buf_state));
>                 asf_tailq_remove(&sc->sc_txbuf, bf, bf_list);
>         } else {
>                 adf_os_assert(0);
>                 ^^^^^^^^^^^^^^
>         }
>
>         return  bf;
> }
>

That's very interesting. I thought from the 0x12345678 it was hitting
one of those asserts but I wasn't sure how to figure out the location
in the firmware.

> What is your reproduction case? WHat is your AP, wireless mode G/N? How
> stable is the connection? Stable transfer rate? How about host usb
> controller?
>
> I will need more data to track it down...

The connection is pretty stable in general. It usually only happens
when downloading a large file, wget/zsync an iso. However recently I
have been hitting it on the upload portion of speedtest.comcast.net.
It isn't always reproducible, I was surprised I hit it so quickly
after updating the firmware. Sometimes I can go days without seeing a
firmware panic.

AP is also a TP-LINK, TL-WR941N, it is in 11bgn mixed mode, I guess it
is using N with the TL-WN821N wireless adapter, but I'm not sure how
to check.

I average about 20mbps download and 5.5mbps upload on the test above,
but I don't usually get that in general. If I hit it while downloading
an iso I noticed the download is about 2.5mbps or higher, but I'm not
always watching when it happens so it could be a coincidence. Between
two machines on my network (one with ath9k and then this machine with
ath9k-htc) I can get a sustained 10mbps both ways, but I haven't been
able to trigger the bug that way.

>From lsusb -t:
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/8p, 480M
    |__ Port 2: Dev 7, If 0, Class=Vendor Specific Class, Driver=ath9k_htc, 480M

Which is:
Bus 001 Device 007: ID 0cf3:7015 Atheros Communications, Inc. TP-Link
TL-WN821N v3 802.11n [Atheros AR7010+AR9287]

Thanks for taking a look, I appreciate it. Let me know if you would
like any more information.

Jason Conti