From: Bart Van Assche <bvanassche@acm.org>
Date: Thu, 26 Mar 2026 21:40:54 +0000 (-0700)
Subject: drbd: Balance RCU calls in drbd_adm_dump_devices()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2b31e86387e60b3689339f0f0fbb4d3623d9d494;p=thirdparty%2Fkernel%2Flinux.git

drbd: Balance RCU calls in drbd_adm_dump_devices()

Make drbd_adm_dump_devices() call rcu_read_lock() before
rcu_read_unlock() is called. This has been detected by the Clang
thread-safety analyzer.

Tested-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Fixes: a55bbd375d18 ("drbd: Backport the "status" command")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260326214054.284593-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index e18fa260a6625..1f8ffdf9b24ef 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -3443,8 +3443,10 @@ int drbd_adm_dump_devices(struct sk_buff *skb, struct netlink_callback *cb)
 		if (resource_filter) {
 			retcode = ERR_RES_NOT_KNOWN;
 			resource = drbd_find_resource(nla_data(resource_filter));
-			if (!resource)
+			if (!resource) {
+				rcu_read_lock();
 				goto put_result;
+			}
 			cb->args[0] = (long)resource;
 		}
 	}
@@ -3693,8 +3695,10 @@ int drbd_adm_dump_peer_devices(struct sk_buff *skb, struct netlink_callback *cb)
 		if (resource_filter) {
 			retcode = ERR_RES_NOT_KNOWN;
 			resource = drbd_find_resource(nla_data(resource_filter));
-			if (!resource)
+			if (!resource) {
+				rcu_read_lock();
 				goto put_result;
+			}
 		}
 		cb->args[0] = (long)resource;
 	}