[patch 16/26] FUTEX: Restore the dropped ERSCH fix

Greg KH
2007-07-31T04:37:08Z

[-- Attachment #1: futex-restore-the-dropped-ersch-fix.patch --]
[-- Type: text/plain, Size: 1221 bytes --]

-stable review patch. If anyone has any objections, please let us know.

------------------

The return value of futex_find_get_task() needs to be -ESRCH in case
that the search fails. This was part of the original futex fixes and
got accidentally dropped, when the futex-tidy-up patch was split out.

Results in a NULL pointer dereference in case the search fails.

Restore it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
kernel/futex.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

--- linux-2.6.21.6.orig/kernel/futex.c
+++ linux-2.6.21.6/kernel/futex.c
@@ -390,14 +390,12 @@ static struct task_struct * futex_find_g

rcu_read_lock();
p = find_task_by_pid(pid);
- if (!p)
- goto out_unlock;
- if ((current->euid != p->euid) && (current->euid != p->uid)) {
- p = NULL;
- goto out_unlock;
- }
- get_task_struct(p);
-out_unlock:
+
+ if (!p || ((current->euid != p->euid) && (current->euid != p->uid)))
+ p = ERR_PTR(-ESRCH);
+ else
+ get_task_struct(p);
+
rcu_read_unlock();

return p;

--