On Wed, 2008-02-20 at 22:36 -0800, David Miller wrote: > From: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> > Date: Wed, 20 Feb 2008 01:56:08 +0100 > > Interestingly, I'm starting to see skb problems as well, in AP mode > > only however, namely I get lots of > > > > [ 4340.665679] SKB BUG: Invalid truesize (240) len=73, sizeof(sk_buff)=176 OK. I started to see this also after I began to play with the AP mode. SKB BUG: Invalid truesize (272) len=71, sizeof(sk_buff)=208 I get this for every ping packet from the AP to the client and only occasionally if I ping AP from client. According to the call trace, it's from the AP receive path. Call Trace: [<ffffffff804101d0>] ? sock_rfree+0x22/0x51 [<ffffffff8041394d>] ? skb_release_all+0x86/0xbe [<ffffffff80413151>] ? __kfree_skb+0x9/0x6f [<ffffffff8041596f>] ? skb_free_datagram+0xc/0x31 [<ffffffff8047a68d>] ? packet_recvmsg+0x174/0x187 [<ffffffff8040d807>] ? sock_recvmsg+0xf0/0x10f [<ffffffff80370499>] ? n_tty_receive_buf+0xdc8/0xe20 [<ffffffff802468d2>] ? autoremove_wake_function+0x0/0x2e [<ffffffff8029aa5b>] ? core_sys_select+0x232/0x263 [<ffffffff80273316>] ? __do_fault+0x38f/0x3da [<ffffffff8040e87c>] ? sys_recvfrom+0xbc/0x120 [<ffffffff8020bfd9>] ? tracesys+0xdc/0xe1 > > Anybody have an idea how to debug that? It looks like 'len' is one too > > large, but I've also seen messages where it was two too large or one to > > small. > > The BUG occurs when you use paged SKBs, it's different from > the other problem the person you are replying to is seeing. > > The easiest thing to do to look for potentially problematic areas > is to find code that modifies skb->data_len but doesn't make > similar adjustments to skb->truesize. >From my search result, most of such code is from tcp/ip and skbuff.c. None from wireless, mac80211 or drivers. Looks like this is not wireless specific? Anyone has made any progress on this? Thanks, -yi -- 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
