Dear James Cameron, On Tue, Oct 14, 2014 at 12:20 PM, James Cameron <quozl@xxxxxxxxxx> wrote: > On Tue, Oct 14, 2014 at 10:25:01AM +0200, Belisko Marek wrote: >> Hi Amitkumar, >> >> On Tue, Oct 14, 2014 at 9:08 AM, Amitkumar Karwar <akarwar@xxxxxxxxxxx> wrote: >> > Hi Marek, >> > >> > > I tried both (slightly modified as we're in 3.9 kernel) but >> > > issue is still reproducible. My patch against 3.9 sources: >> > >> > Thanks a lot for the tests. >> > >> > > One thing which is not yet still clear to me why kernel console >> > > is completely unresponsive when receiving packets in high >> > > rates. When use iperf (on client) with -b40m it is OK but when >> > > increase to -b100m then console is completely unresponsive until >> > > iperf finish. >> > >> > Does the system recover when "-b100M" iperf is finished? Can we >> > run iperf with "-b40M" later? Do you see "dev_alloc_skb failed" >> > messages in dmesg when console is unresponsive? >> When we get "dev_alloc_skb failed" then interface is dead (cannot >> ping ...) so no recovery is possible only system reboot. > > This symptom was familiar to me, but on sdio.c, which is very > different code. > > I've had a brief look at usb.c and offer the following comments: > > - a list of six data endpoint urb is allocated in mwifiex_usb_rx_init, > because MWIFIEX_RX_DATA_URB is 6, > > - when data endpoint urb is submitted, a new skb is allocated, in > mwifiex_usb_submit_rx_urb, and this is the only source of > "dev_alloc_skb failed" message, > > - in normal situation, when data endpoint urb is complete, skb is > either freed or handed up to mwifiex_usb_recv, and the urb is > resubmitted, which causes a new skb to be allocated. > > - if "dev_alloc_skb failed" message appears, one data endpoint urb has > been lost and is not re-used, > > - if six "dev_alloc_skb failed" messages appear, the interface should > be dead for data receive only. > > Amitkumar mentioned this on 9th October; "corresponding URB won't get > submitted". I think this should be fixed; dev_alloc_skb should be > harmless failure, please retry. > > I don't see why interface is dead with only one "dev_alloc_skb > failed" message. Maybe my description wasn't not correct. I see 6 "dev_alloc_skb failed" messages and then interface is dead as you wrote. > >> I don't see dev_alloc_skb failed when console is unresponsive. >> > >> > > Any other ideas >> > > what to change to check? Thanks. >> > >> > Could you please share dmesg log with dynamic debug enabled (using >> > attached script) captured when the problem occurs? >> I tried to capture logs but when enable DYNAMIC_DEBUG I cannot >> reproduce issue (running test > 30 minutes without allocation >> failure). > > Yes, I've seen similar; turn on debugging, and timing critical bug > goes away. > > Serial console? If so, try turning it off, and logging to dmesg > buffer only. When turning off serial console how then I get kernel messages from dmesg buffer? > > -- > James Cameron > http://quozl.linux.org.au/ BR, marek -- as simple and primitive as possible ------------------------------------------------- Marek Belisko - OPEN-NANDRA Freelance Developer Ruska Nova Ves 219 | Presov, 08005 Slovak Republic Tel: +421 915 052 184 skype: marekwhite twitter: #opennandra web: http://open-nandra.com -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
