setpgid(child) fails if the child was forked by sub-thread
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>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: <stable@kernel.org>
Tested-by: "Marcin 'Qrczak' Kowalczyk" <qrczak@knm.org.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/sys.c b/kernel/sys.c
index 449b81b..1b33b05 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1442,7 +1442,6 @@
* 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 @@
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;