6.16-stable review patch. If anyone has any objections, please let me know.
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From: Sebastian Andrzej Siewior bigeasy@linutronix.de
[ Upstream commit 4ec3c15462b9f44562f45723a92e2807746ba7d1 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/fork.c b/kernel/fork.c index 1ee8eb11f38ba..0cbc174da76ac 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2289,7 +2289,7 @@ __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