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authorChristian Borntraeger <borntraeger@de.ibm.com>2009-10-26 16:49:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-10-29 07:39:25 -0700
commit0d0df599f1f11f12d589318bacb59a50fb5c0310 (patch)
tree084ab3d1562502ad6a056aa3fd8dd748683c8c2f /kernel
parent370c28def65b3a5765192753a164403619b41d01 (diff)
downloadlinux-0d0df599f1f11f12d589318bacb59a50fb5c0310.tar.bz2
connector: fix regression introduced by sid connector
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> Cc: Scott James Remnant <scott@ubuntu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/exit.c4
-rw-r--r--kernel/sys.c2
2 files changed, 3 insertions, 3 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index e61891f80123..f7864ac2ecc1 100644
--- a/kernel/exit.c
+++ b/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);
diff --git a/kernel/sys.c b/kernel/sys.c
index 255475d163e0..1828f8d10844 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1110,6 +1110,8 @@ SYSCALL_DEFINE0(setsid)
err = session;
out:
write_unlock_irq(&tasklist_lock);
+ if (err > 0)
+ proc_sid_connector(group_leader);
return err;
}