On Tue, Dec 11, 2012 at 3:31 PM, Cedric VONCKEN <cedric.voncken@xxxxxxxxx> wrote: > Any suggestion to fix correctly this issue ? having a count to break out from the loop is bit hacky. I would suggest to enable as many prints and see why the infinite loop counts(ofcourse you can have a loop count to figure out and break the loop). > > Best regards. > > -----Message d'origine----- > De : Cedric VONCKEN > Envoyé : vendredi 7 décembre 2012 16:28 > À : 'linux-wireless@xxxxxxxxxxxxxxx' > Objet : [RFC] ATH9K: infinite loop in Tasklet > > Dear mailling list, > > I think there is a possible infinite loop in ATH9K tasklet, and this loop block the linux kernel. > > In my test based on freescale MPC8315 cpu, the Wireless card is bridged to Ethernet driver (Gianfar). When I receive data from Wifi (iperf -c xx -b50M) to Ethernet, the Gianfar NAPI poll function is never called because the ath_rx_tasklet always loops. > > In the ath_rx_tasklet(...), the "while" loops until ath_get_next_rx_buf() or ath_edma_get_next_rx_buf returns a buffer. > > If these functions always return a buffer, this tasklet always runs. While this tasklet runs, all other tasklets are blocked. > To fix it I applied this patch: > > --- recv.c 2012-12-07 14:30:26.000000000 +0100 > +++ recv.c.new 2012-12-07 14:30:05.364591961 +0100 > @@ -1067,6 +1067,7 @@ > u64 tsf = 0; > u32 tsf_lower = 0; > unsigned long flags; > + int count = 150; > > if (edma) > dma_type = DMA_BIDIRECTIONAL; > @@ -1085,6 +1086,10 @@ > if (test_bit(SC_OP_RXFLUSH, &sc->sc_flags) && (flush == 0)) > break; > > + if(count <= 0) > + break; > + > + count --; > memset(&rs, 0, sizeof(rs)); > if (edma) > bf = ath_edma_get_next_rx_buf(sc, &rs, qtype); > > I think this solution is not correct, because the tasklet is not rescheduled and we always have data in Rx buffer. > > Have you any suggestion to fix this issue correctly? > > Thanks for your help. > > Best regards. > > -- > 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 -- thanks, shafi -- 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
