Re: [PATCH] connector: Fix sid connector (was: Badness at kernel/softirq.c:143...)

From: Evgeniy Polyakov
Date: Tue Sep 29 2009 - 10:54:20 EST


On Tue, Sep 29, 2009 at 04:25:38PM +0200, Oleg Nesterov (oleg@xxxxxxxxxx) wrote:
> > --- 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;
>
> This is not right, task_session(group_leader) must be == sid after
> __set_special_pids().

Yeah, that check should be done before __set_special_pids().

> And I don't think "int send_cn" is needed. sys_setsid() must not
> succeed if the caller lived in session == task_pid(group_leader).

Doesn't it only check pgid while patch intention was to send
notification about sid? I.e. setsid() succeeds, although nothing
happens.

--
Evgeniy Polyakov
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