From: Christian Brauner <brauner@kernel.org>
Date: Tue, 16 Jul 2024 07:19:11 +0000 (+0200)
Subject: nsfs: use cleanup guard
X-Git-Tag: io_uring-6.11-20240722~31^2
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=280e36f0d5b997173d014c07484c03a7f7750668;p=linux-block.git

nsfs: use cleanup guard

Ensure that rcu read lock is given up before returning.

Link: https://lore.kernel.org/r/20240716-elixier-fliesen-1ab342151a61@brauner
Fixes: ca567df74a28 ("nsfs: add pid translation ioctls")
Reported-by: syzbot+a3e82ae343b26b4d2335@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
---

diff --git a/fs/nsfs.c b/fs/nsfs.c
index a4a925dce331..97c37a9631e5 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -174,14 +174,14 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl,
 		fallthrough;
 	case NS_GET_PID_IN_PIDNS:
 		fallthrough;
-	case NS_GET_TGID_IN_PIDNS:
+	case NS_GET_TGID_IN_PIDNS: {
 		if (ns->ops->type != CLONE_NEWPID)
 			return -EINVAL;
 
 		ret = -ESRCH;
 		pid_ns = container_of(ns, struct pid_namespace, ns);
 
-		rcu_read_lock();
+		guard(rcu)();
 
 		if (ioctl == NS_GET_PID_IN_PIDNS ||
 		    ioctl == NS_GET_TGID_IN_PIDNS)
@@ -208,11 +208,11 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl,
 			ret = 0;
 			break;
 		}
-		rcu_read_unlock();
 
 		if (!ret)
 			ret = -ESRCH;
 		break;
+	}
 	default:
 		ret = -ENOTTY;
 	}