Messages in this thread | | | Date | Tue, 13 Oct 2009 17:53:30 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH] connector: Fix regression introduced by sid connector |
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On Fri, 2 Oct 2009, Christian Borntraeger wrote:
> since commit 02b51df1b07b4e9ca823c89284e704cadb323cd1 (proc connector: add event > for process becoming session leader) we have the following warning: > Badness at kernel/softirq.c:143 > [...] > Krnl PSW : 0404c00180000000 00000000001481d4 (local_bh_enable+0xb0/0xe0) > [...] > 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. > After a discussion we agreed that we can move proc_sid_connector > from __set_special_pids to sys_setsid. > We also agreed that it is sufficient to change the check from > task_session(curr) != pid into err > 0, since if we don't change the > session, this means we were already the leader and return -EPERM. > > One last thing: > There is also daemonize(), and some people might want to get a > notification in that case. Since daemonize() is only needed if a user > space does kernel_thread this does not look important (and there seems > to be no consensus if this connector should be called in daemonize). If > we really want this, we can add proc_sid_connector to daemonize() in an > additional patch (Scott?) > > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > CCed: Scott James Remnant <scott@ubuntu.com> > CCed: Matt Helsley <matthltc@us.ibm.com> > CCed: David S. Miller <davem@davemloft.net> > Acked-by: Oleg Nesterov <oleg@redhat.com> > Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Acked-by: David Rientjes <rientjes@google.com>
I was getting the same softirq warnings and later in slub in slab_alloc() at might_sleep_if(gfpflags & __GFP_WAIT) from __alloc_skb(..., GFP_KERNEL) in this context that would infinitely spam my log.
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