From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Borntraeger Subject: [PATCH] connector: Fix sid connector (was: Badness at kernel/softirq.c:143...) Date: Tue, 29 Sep 2009 15:47:21 +0200 Message-ID: <200909291547.21528.borntraeger@de.ibm.com> References: <200909251123.03482.borntraeger@de.ibm.com> <20090929132415.GB4538@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: Evgeny Polyakov , Scott James Remnant , Linux Kernel , Matt Helsley , "David S. Miller" , Evgeniy Polyakov , netdev@vger.kernel.org To: Oleg Nesterov Return-path: Received: from mtagate1.uk.ibm.com ([194.196.100.161]:41701 "EHLO mtagate1.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751932AbZI2NrU (ORCPT ); Tue, 29 Sep 2009 09:47:20 -0400 In-Reply-To: <20090929132415.GB4538@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: Am Dienstag 29 September 2009 15:24:15 schrieb Oleg Nesterov: > On 09/29, Evgeny Polyakov wrote: > > I'm yet do download the latest git to check this particular patch, but > > I suppose it is possible to copy data under the lock into temporary > > buffer and then send it using existing infrastructure instead of > > calling it under the tasklist lock. > > Afaics, we can just shift proc_sid_connector() from __set_special_pids() > to sys_setsid(). Ok, can confirm that this patch fixes my problem, but I am not sure if the intended behaviour is still working as expected. [PATCH] connector: Fix sid connector The sid connector gives the following warning: Badness at kernel/softirq.c:143 [...] Call Trace: ([<000000013fe04100>] 0x13fe04100) [<000000000048a946>] sk_filter+0x9a/0xd0 [<000000000049d938>] netlink_broadcast+0x2c0/0x53c [<00000000003ba9ae>] cn_netlink_send+0x272/0x2b0 [<00000000003baef0>] proc_sid_connector+0xc4/0xd4 [<0000000000142604>] __set_special_pids+0x58/0x90 [<0000000000159938>] sys_setsid+0xb4/0xd8 [<00000000001187fe>] sysc_noemu+0x10/0x16 [<00000041616cb266>] 0x41616cb266 The warning is ---> WARN_ON_ONCE(in_irq() || irqs_disabled()); The network code must not be called with disabled interrupts but sys_setsid holds the tasklist_lock with spinlock_irq while calling the connector. We can safely move proc_sid_connector from __set_special_pids to sys_setsid. Signed-off-by: Christian Borntraeger --- kernel/exit.c | 4 +--- kernel/sys.c | 2 ++ 2 files changed, 3 insertions(+), 3 deletions(-) Index: linux-2.6/kernel/exit.c =================================================================== --- linux-2.6.orig/kernel/exit.c +++ linux-2.6/kernel/exit.c @@ -359,10 +359,8 @@ void __set_special_pids(struct pid *pid) { struct task_struct *curr = current->group_leader; - if (task_session(curr) != pid) { + if (task_session(curr) != pid) change_pid(curr, PIDTYPE_SID, pid); - proc_sid_connector(curr); - } if (task_pgrp(curr) != pid) change_pid(curr, PIDTYPE_PGID, pid); Index: linux-2.6/kernel/sys.c =================================================================== --- linux-2.6.orig/kernel/sys.c +++ linux-2.6/kernel/sys.c @@ -1110,6 +1110,8 @@ SYSCALL_DEFINE0(setsid) err = session; out: write_unlock_irq(&tasklist_lock); + if (!err) + proc_sid_connector(sid); return err; }