Re: [PATCH] setpgid(child) fails if the child was forked bysub-thread

[Randy Dunlap]

On Wed, 22 Aug 2007 20:55:39 +0400 Oleg Nesterov wrote:


so "fixes http://bugzilla.kernel.org/show_bug.cgi?id=8921";  ??


> Spotted by Marcin Kowalczyk <qrczak@xxxxxxxxxx>.
> 
> sys_setpgid(child) fails if the child was forked by sub-thread.
> 
> Fix the "is it our child" check. The previous commit
> ee0acf90d320c29916ba8c5c1b2e908d81f5057d was not complete.
> 
> (this patch asks for the new same_thread_group() helper, but mainline doesn't
>  have it yet).
> 
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> 
> --- t/kernel/sys.c~SETPGID	2007-08-09 19:59:27.000000000 +0400
> +++ t/kernel/sys.c	2007-08-22 20:11:23.000000000 +0400
> @@ -1442,7 +1442,6 @@ asmlinkage long sys_times(struct tms __u
>   * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
>   * LBT 04.03.94
>   */
> -
>  asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
>  {
>  	struct task_struct *p;
> @@ -1470,7 +1469,7 @@ asmlinkage long sys_setpgid(pid_t pid, p
>  	if (!thread_group_leader(p))
>  		goto out;
>  
> -	if (p->real_parent == group_leader) {
> +	if (p->real_parent->tgid == group_leader->tgid) {
>  		err = -EPERM;
>  		if (task_session(p) != task_session(group_leader))
>  			goto out;
> 
> -

---
~Randy
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