| Message ID | 20090915230126.GA21539@hq.alert.sk |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Robert Varga <nite@hq.alert.sk> Date: Wed, 16 Sep 2009 01:01:26 +0200 > Hi, > > I have recently came across a preemption imbalance detected by: > > <4>huh, entered ffffffff80644630 with preempt_count 00000102, exited with 00000101? > <0>------------[ cut here ]------------ > <2>kernel BUG at /usr/src/linux/kernel/timer.c:664! > <0>invalid opcode: 0000 [1] PREEMPT SMP > > with ffffffff80644630 being inet_twdr_hangman(). > > This appeared after I enabled CONFIG_TCP_MD5SIG and played with it a > bit, so I looked at what might have caused it. > > One thing that struck me as strange is tcp_twsk_destructor(), as it > calls tcp_put_md5sig_pool() -- which entails a put_cpu(), causing the > detected imbalance. Found on 2.6.23.9, but 2.6.31 is affected as well, > as far as I can tell. > > Signed-off-by: Robert Varga <nite@hq.alert.sk> Looks good, applied and queued up for stable. Thanks! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- vanilla/net/ipv4/tcp_minisocks.c 2009-09-10 00:13:59.000000000 +0200 +++ patched/net/ipv4/tcp_minisocks.c 2009-09-16 00:48:15.904089024 +0200 @@ -363,7 +363,7 @@ void tcp_twsk_destructor(struct sock *sk #ifdef CONFIG_TCP_MD5SIG struct tcp_timewait_sock *twsk = tcp_twsk(sk); if (twsk->tw_md5_keylen) - tcp_put_md5sig_pool(); + tcp_free_md5sig_pool(); #endif }
Hi, I have recently came across a preemption imbalance detected by: <4>huh, entered ffffffff80644630 with preempt_count 00000102, exited with 00000101? <0>------------[ cut here ]------------ <2>kernel BUG at /usr/src/linux/kernel/timer.c:664! <0>invalid opcode: 0000 [1] PREEMPT SMP with ffffffff80644630 being inet_twdr_hangman(). This appeared after I enabled CONFIG_TCP_MD5SIG and played with it a bit, so I looked at what might have caused it. One thing that struck me as strange is tcp_twsk_destructor(), as it calls tcp_put_md5sig_pool() -- which entails a put_cpu(), causing the detected imbalance. Found on 2.6.23.9, but 2.6.31 is affected as well, as far as I can tell. Signed-off-by: Robert Varga <nite@hq.alert.sk> ---