[PATCH] setpgid(child) fails if the child was forked by sub-thread

[PATCH] setpgid(child) fails if the child was forked by sub-thread

[Oleg Nesterov]

Spotted by Marcin Kowalczyk <qrczak@knm.org.pl>.

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@tv-sign.ru>

--- 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;

Re: [PATCH] setpgid(child) fails if the child was forked by sub-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@knm.org.pl>.
> 
> 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@tv-sign.ru>
> 
> --- 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
*** Remember to use Documentation/SubmitChecklist when testing your code ***

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

[Oleg Nesterov]

On 08/22, Randy Dunlap wrote:
>
> On Wed, 22 Aug 2007 20:55:39 +0400 Oleg Nesterov wrote:
> 
> 
> so "fixes http://bugzilla.kernel.org/show_bug.cgi?id=8921"  ??

Hopefully yes... should I add some note at /bugzilla.kernel.org?

Oleg.

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

[Randy Dunlap]

On Wed, 22 Aug 2007 21:24:36 +0400 Oleg Nesterov wrote:

> On 08/22, Randy Dunlap wrote:
> >
> > On Wed, 22 Aug 2007 20:55:39 +0400 Oleg Nesterov wrote:
> > 
> > 
> > so "fixes http://bugzilla.kernel.org/show_bug.cgi?id=8921"  ??
> 
> Hopefully yes... should I add some note at /bugzilla.kernel.org?

I think that it can wait until Marcin confirms that it's fixed
(if he does so soon), then mark 8921 as fixed.


---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***

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

[Marcin 'Qrczak' Kowalczyk]

Dnia 22-08-2007, Śr o godzinie 10:30 -0700, Randy Dunlap napisał(a):

> > > so "fixes http://bugzilla.kernel.org/show_bug.cgi?id=8921"  ??
> > 
> > Hopefully yes... should I add some note at /bugzilla.kernel.org?
> 
> I think that it can wait until Marcin confirms that it's fixed
> (if he does so soon), then mark 8921 as fixed.

Yes, it's fixed. Thank you!

-- 
   __("<         Marcin Kowalczyk
   \__/       qrczak@knm.org.pl
    ^^     http://qrnik.knm.org.pl/~qrczak/