futex: Use correct exit on failure from futex_hash_allocate_default()

copy_process() uses the wrong error exit path from futex_hash_allocate_default().
After exiting from futex_hash_allocate_default(), neither tasklist_lock
nor siglock has been acquired. The exit label bad_fork_core_free unlocks
both of these locks which is wrong.

The next exit label, bad_fork_cancel_cgroup, is the correct exit.
sched_cgroup_fork() did not allocate any resources that need to freed.

Use bad_fork_cancel_cgroup on error exit from futex_hash_allocate_default().

Fixes: 7c4f75a21f636 ("futex: Allow automatic allocation of process wide futex hash")
Reported-by: syzbot+80cb3cc5c14fad191a10@syzkaller.appspotmail.com
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Closes: https://lore.kernel.org/all/68cb1cbd.050a0220.2ff435.0599.GAE@google.com

diff --git a/kernel/fork.c b/kernel/fork.c
index c4ada32598bd5e137ea13efd0d1117da9e746114..6ca8689a83b5bd66e042c424f1995511b16e982f 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2295,7 +2295,7 @@ __latent_entropy struct task_struct *copy_process(
        if (need_futex_hash_allocate_default(clone_flags)) {
                retval = futex_hash_allocate_default();
                if (retval)
-                       goto bad_fork_core_free;
+                       goto bad_fork_cancel_cgroup;
                /*
                 * If we fail beyond this point we don't free the allocated
                 * futex hash map. We assume that another thread will be created