Search Linux Wireless

RE: [RFC] ATH9K: infinite loop in Tasklet

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



	Any suggestion to fix correctly this issue ?

	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


[Index of Archives]     [Linux Host AP]     [ATH6KL]     [Linux Wireless Personal Area Network]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Linux Kernel]     [IDE]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Hiking]     [MIPS Linux]     [ARM Linux]     [Linux RAID]

  Powered by Linux