Messages in this thread |  | | | Date | Mon, 24 Mar 2008 10:39:41 +0300 | | From | Oleg Nesterov <> | | Subject | Re: [PATCH] pids: sys_getsid: make sure we don't return 0 instead of -ESRCH | |
Sorry! please ignore this patch and
"[PATCH] pids: sys_getpgid: use rcu_read_lock() instead of tasklist_lock",
I'll send the updated version.
It turns out that sys_getsid/sys_getpgid have other problems which should
be fixed.
On 03/23, Oleg Nesterov wrote:
>
> The task can exit between find_task_by_vpid() and task_session_vnr(), in
> that unlikely case sys_getsid() returns 0 instead of -ESRCH.
>
> The bug was introduced by me in ac9a8e3f0f43d20fc316162e8e5f9186d295ff49.
>
> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
>
> --- 25/kernel/sys.c~1_GETSID 2008-03-20 18:21:17.000000000 +0300
> +++ 25/kernel/sys.c 2008-03-23 19:25:36.000000000 +0300
> @@ -1019,19 +1019,19 @@ asmlinkage long sys_getsid(pid_t pid)
> if (!pid)
> return task_session_vnr(current);
> else {
> - int retval;
> + int retval = 0;
> struct task_struct *p;
>
> rcu_read_lock();
> p = find_task_by_vpid(pid);
> - retval = -ESRCH;
> if (p) {
> retval = security_task_getsid(p);
> if (!retval)
> retval = task_session_vnr(p);
> }
> rcu_read_unlock();
> - return retval;
> +
> + return retval ?: -ESRCH;
> }
> }
>
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