• Sergei Shtylyov's avatar
    sh_eth: fix kernel oops in skb_put() · 248be83d
    Sergei Shtylyov authored
    In a low memory situation the following kernel oops occurs:
    
    Unable to handle kernel NULL pointer dereference at virtual address 00000050
    pgd = 8490c000
    [00000050] *pgd=4651e831, *pte=00000000, *ppte=00000000
    Internal error: Oops: 17 [#1] PREEMPT ARM
    Modules linked in:
    CPU: 0    Not tainted  (3.4-at16 #9)
    PC is at skb_put+0x10/0x98
    LR is at sh_eth_poll+0x2c8/0xa10
    pc : [<8035f780>]    lr : [<8028bf50>]    psr: 60000113
    sp : 84eb1a90  ip : 84eb1ac8  fp : 84eb1ac4
    r10: 0000003f  r9 : 000005ea  r8 : 00000000
    r7 : 00000000  r6 : 940453b0  r5 : 00030000  r4 : 9381b180
    r3 : 00000000  r2 : 00000000  r1 : 000005ea  r0 : 00000000
    Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
    Control: 10c53c7d  Table: 4248c059  DAC: 00000015
    Process klogd (pid: 2046, stack limit = 0x84eb02e8)
    [...]
    
    This is  because netdev_alloc_skb() fails and 'mdp->rx_skbuff[entry]' is left
    NULL but sh_eth_rx() later  uses it without checking.  Add such check...
    Reported-by: default avatarYasushi SHOJI <yashi@atmark-techno.com>
    Signed-off-by: default avatarSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    248be83d
sh_eth.c 78 KB