Messages in this thread Patch in this message | | | Date | Tue, 29 Sep 2009 18:07:18 +0400 | From | Evgeniy Polyakov <> | Subject | Re: [PATCH] connector: Fix sid connector (was: Badness at kernel/softirq.c:143...) |
| |
On Tue, Sep 29, 2009 at 03:47:21PM +0200, Christian Borntraeger (borntraeger@de.ibm.com) wrote: > Ok, can confirm that this patch fixes my problem, but I am not sure if the > intended behaviour is still working as expected.
Your patch breaks assumption that task_session(current->group_leader) is not equal to new session id, but to check task_session() we need either rcu or task lock. Also setsid() return value is not zero or negative error, but new session ID or negative error, so I believe attached patch is a proper fix, although it looks rather ugly.
Also proc_sid_connector() uses GFP_KERNEL allocation which is way too wrong to use under any locks.
Something like this (not tested :)
diff --git a/kernel/exit.c b/kernel/exit.c index 5859f59..1565baf 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 255475d..b852a8b 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1090,6 +1090,7 @@ SYSCALL_DEFINE0(setsid) struct pid *sid = task_pid(group_leader); pid_t session = pid_vnr(sid); int err = -EPERM; + int send_cn = 0; write_lock_irq(&tasklist_lock); /* Fail if I am already a session leader */ @@ -1104,12 +1105,18 @@ SYSCALL_DEFINE0(setsid) group_leader->signal->leader = 1; __set_special_pids(sid); + if (task_session(group_leader) != sid) + send_cn = 1; proc_clear_tty(group_leader); err = session; out: write_unlock_irq(&tasklist_lock); + + if (send_cn) + proc_sid_connector(group_leader); + return err; } -- Evgeniy Polyakov
| |