Re: [PATCH] /proc/net/tcp + ipv6 hang

Anders Gustafsson (andersg@0x63.nu)
Mon, 23 Dec 2002 04:08:12 +0100

On Mon, Dec 23, 2002 at 12:40:17AM -0200, Arnaldo Carvalho de Melo wrote:
>
> Anders, if you're feeling brave, from the top of my head, think about what
> happens if somebody only reads the first, say, 10 bytes of /proc/net/tcp, will
> we unlocking a not held lock at tcp_seq_stop, no? :-)

Yes, I was just looking into the locking... But it's rather messy with locks
between calls and goto's and I think I'd better get some sleep before saying
anything for certain. Is there any reason holding the lock between
listening_get_first() and the first call to listening_get_next(), but not
between consecutive calls to listening_get_next()? Otherwise we could just
always release the lock in listening_get_first.

(All this applies to established_get_first/next too.)

OOPS, I just realizes we might be talking about different locks :)

I was talking about
read_[un]lock_bh(&tp->syn_wait_lock); in listening_get_first/next

What lock are you talking about?
As far as I can see, in TCP_SEQ_STATE_OPENREQ tp->syn_wait_lock is always
held and in TCP_SEQ_STATE_LISTENING the tcp_listen_lock and so on?

-- 
Anders Gustafsson - andersg@0x63.nu - http://0x63.nu/
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