Dear all,
I am a newbie to pf ring and kernel program. I added several lines follow the
calling of add_skb_to_ring in pf_ring/kernel/pf_ring.c to do something extra I
need. It looks like:
from line 2556 fo kernel/pf_ring.c
if((pfr != NULL)
&& (pfr->ring_netdev != &none_dev) /* Not a dummy socket bound to "none"
*/
&& (pfr->cluster_id == 0 /* No cluster */ )
&& (pfr->ring_slots != NULL)
&& is_valid_skb_direction(pfr->direction, recv_packet)
&& ((pfr->ring_netdev == skb->dev)
|| (pfr->ring_netdev == &any_dev) /* Socket bound to 'any' */
|| ((skb->dev->flags & IFF_SLAVE) && (pfr->ring_netdev ==
skb->dev->master)))) {
/* We've found the ring where the packet can be stored */
int old_caplen = hdr.caplen; /* Keep old lenght */
hdr.caplen = min(hdr.caplen, pfr->bucket_len);
add_skb_to_ring(skb, pfr, &hdr, is_ip_pkt, displ, channel_id,
num_rx_channels);
my_function_here(skb);
hdr.caplen = old_caplen;
rc = 1; /* Ring found: we've done our job */
}
In my_function_here(), I just kmalloc some byte with GFP_KERNEL and the kfree
it. When I run this code, the kernel always crashes with message:BUG:
scheduling while atomic
I think this is because kmalloc with GFP_KERNEL, but I noticed that in
add_skb_to_ring() there is kcalloc with GFP_KERNEL! Why this is safe and my
code cause kernel crash?
Thank you for your time!
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