[10/73] tcp: fix inet_twsk_deschedule()

From: Greg KH
Date: Fri Mar 04 2011 - 20:18:48 EST


2.6.37-stable review patch. If anyone has any objections, please let us know.

------------------

From: Eric Dumazet <eric.dumazet@xxxxxxxxx>

commit 91035f0b7d89291af728b6f3e370c3be58fcbe1b upstream.

Eric W. Biederman reported a lockdep splat in inet_twsk_deschedule()

This is caused by inet_twsk_purge(), run from process context,
and commit 575f4cd5a5b6394577 (net: Use rcu lookups in inet_twsk_purge.)
removed the BH disabling that was necessary.

Add the BH disabling but fine grained, right before calling
inet_twsk_deschedule(), instead of whole function.

With help from Linus Torvalds and Eric W. Biederman

Reported-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
CC: Daniel Lezcano <daniel.lezcano@xxxxxxx>
CC: Pavel Emelyanov <xemul@xxxxxxxxxx>
CC: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
net/ipv4/inet_timewait_sock.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -505,7 +505,9 @@ restart:
}

rcu_read_unlock();
+ local_bh_disable();
inet_twsk_deschedule(tw, twdr);
+ local_bh_enable();
inet_twsk_put(tw);
goto restart_rcu;
}


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