• Anton Vorontsov's avatar
    skbuff: Do not allow skb recycling with disabled IRQs · e84af6dd
    Anton Vorontsov authored
    NAPI drivers try to recycle SKBs in their polling routine, but we
    generally don't know the context in which the polling will be called,
    and the skb recycling itself may require IRQs to be enabled.
    
    This patch adds irqs_disabled() test to the skb_recycle_check()
    routine, so that we'll not let the drivers hit the skb recycling
    path with IRQs disabled.
    
    As a side effect, this patch actually disables skb recycling for some
    [broken] drivers. E.g. gianfar driver grabs an irqsave spinlock during
    TX ring processing, and then tries to recycle an skb, and that caused
    the following badness:
    
    nf_conntrack version 0.5.0 (1008 buckets, 4032 max)
    ------------[ cut here ]------------
    Badness at kernel/softirq.c:143
    NIP: c003e3c4 LR: c423a528 CTR: c003e344
    ...
    NIP [c003e3c4] local_bh_enable+0x80/0xc4
    LR [c423a528] destroy_conntrack+0xd4/0x13c [nf_conntrack]
    Call Trace:
    [c15d1b60] [c003e32c] local_bh_disable+0x1c/0x34 (unreliable)
    [c15d1b70] [c423a528] destroy_conntrack+0xd4/0x13c [nf_conntrack]
    [c15d1b80] [c02c6370] nf_conntrack_destroy+0x3c/0x70
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    e84af6dd
skbuff.c 74.3 KB