• Anton Vorontsov's avatar
    ucc_geth: Fix empty TX queue processing · 7583605b
    Anton Vorontsov authored
    Following oops was seen with the ucc_geth driver:
    
     Unable to handle kernel paging request for data at address 0x00000058
     Faulting instruction address: 0xc024f2fc
     Oops: Kernel access of bad area, sig: 11 [#1]
     [...]
     NIP [c024f2fc] skb_recycle_check+0x14/0x100
     LR [e30aa0a4] ucc_geth_poll+0xd8/0x4e0 [ucc_geth_driver]
     Call Trace:
     [df857d50] [c000b03c] __ipipe_grab_irq+0x3c/0xa4 (unreliable)
     [df857d60] [e30aa0a4] ucc_geth_poll+0xd8/0x4e0 [ucc_geth_driver]
     [df857dd0] [c0258cf8] net_rx_action+0xf8/0x1b8
     [df857e10] [c0032a38] __do_softirq+0xb8/0x13c
     [df857e60] [c00065cc] do_softirq+0xa0/0xac
     [...]
    
    This is because ucc_geth_tx() tries to process an empty queue when
    queues are logically stopped. Stopping the queues doesn't disable
    polling, and since nowadays ucc_geth_tx() is actually called from
    the polling routine, the oops above might pop up.
    
    Fix this by removing 'netif_queue_stopped() == 0' check.
    Reported-by: default avatarLennart Sorensen <lsorense@csclub.uwaterloo.ca>
    Signed-off-by: default avatarAnton Vorontsov <avorontsov@ru.mvista.com>
    Tested-by: default avatarLennart Sorensen <lsorense@csclub.uwaterloo.ca>
    Cc: Stable <stable@vger.kernel.org> [2.6.32]
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    7583605b
ucc_geth.c 119 KB