linux-kernel - Re: [PATCH v2] fs/netfs: fix reference leak

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Message-ID: <928030.1758792736@warthog.procyon.org.uk>
Date: Thu, 25 Sep 2025 10:32:16 +0100
From: David Howells <dhowells@...hat.com>
To: Max Kellermann <max.kellermann@...os.com>
Cc: dhowells@...hat.com, Paulo Alcantara <pc@...guebit.org>,
    Christian Brauner <brauner@...nel.org>, netfs@...ts.linux.dev,
    linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
    stable@...r.kernel.org
Subject: Re: [PATCH v2] fs/netfs: fix reference leak

Hi Max,

I'm going to make the attached change to log the refcount and then post as v3
for Christian to pick up.

David
---
diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c
index 39d5e13f7248..40a1c7d6f6e0 100644
--- a/fs/netfs/objects.c
+++ b/fs/netfs/objects.c
@@ -179,13 +179,15 @@ void netfs_put_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace
  */
 void netfs_put_failed_request(struct netfs_io_request *rreq)
 {
+	int r = refcount_read(&rreq->ref);
+
 	/* new requests have two references (see
 	 * netfs_alloc_request(), and this function is only allowed on
 	 * new request objects
 	 */
-	WARN_ON_ONCE(refcount_read(&rreq->ref) != 2);
+	WARN_ON_ONCE(r != 2);
 
-	trace_netfs_rreq_ref(rreq->debug_id, 0, netfs_rreq_trace_put_failed);
+	trace_netfs_rreq_ref(rreq->debug_id, r, netfs_rreq_trace_put_failed);
 	netfs_free_request(&rreq->cleanup_work);
 }