From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 65087481DD; Wed, 5 Mar 2025 17:55:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197335; cv=none; b=NFRsqj0tldWpwOOK2dx+z6h2Ven2EOaHOHhq41peAauRZnt3lNNlm1DBuJ28DmoRFYwhCL5gKNPgR4dTtGUryNh4uqdBeyV0MqKkQSEC9SHviPsQtj+N63U/pxHZRrcmpEdYSkUh+INQ6v/JJRw+pkwDmfZ6R74aW5VAgD+kQ+s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197335; c=relaxed/simple; bh=y+FTU1VqqOayDWrRQVRQ0OcY9ON4zNJMufF+WDjxpHQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QaTzIfXNRb1wqvGbCVKg5KsBmqU3Bcro50bo6eTGRVlC7NuLcI7nTbJPQ1wCsPKeQOBFmqV95tZqwveVMNVYoG8N3yBbjl/t277e3CfsQVAxLEEnqOILKs/t5XcdYuXUTBShqX54DWACmT31sDNv5SgiyDbmGbY96yHZrBtv0w0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QjaqcwWO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="QjaqcwWO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC44CC4CED1; Wed, 5 Mar 2025 17:55:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741197335; bh=y+FTU1VqqOayDWrRQVRQ0OcY9ON4zNJMufF+WDjxpHQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QjaqcwWOuOjiEpnh+w80KoMPcGR5MFdQx5y6Mdmv+nDfGZdEdMqJIOdvqVWmEQLtU d0ta63eP/a1jdlIdEHihVB6K6NhlwMg8FNREiQxQ4RExxOwgRgYOKfVzuCQkSOhuRf Vemjo11oZeY7QGIghOTxkIUqG8Dbj/uwv14UduPg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Howells , Marc Dionne , Simon Horman , linux-afs@lists.infradead.org, Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 120/176] afs: Fix the server_list to unuse a displaced server rather than putting it Date: Wed, 5 Mar 2025 18:48:09 +0100 Message-ID: <20250305174510.275407552@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250305174505.437358097@linuxfoundation.org> References: <20250305174505.437358097@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Howells [ Upstream commit add117e48df4788a86a21bd0515833c0a6db1ad1 ] When allocating and building an afs_server_list struct object from a VLDB record, we look up each server address to get the server record for it - but a server may have more than one entry in the record and we discard the duplicate pointers. Currently, however, when we discard, we only put a server record, not unuse it - but the lookup got as an active-user count. The active-user count on an afs_server_list object determines its lifetime whereas the refcount keeps the memory backing it around. Failing to reduce the active-user counter prevents the record from being cleaned up and can lead to multiple copied being seen - and pointing to deleted afs_cell objects and other such things. Fix this by switching the incorrect 'put' to an 'unuse' instead. Without this, occasionally, a dead server record can be seen in /proc/net/afs/servers and list corruption may be observed: list_del corruption. prev->next should be ffff888102423e40, but was 0000000000000000. (prev=ffff88810140cd38) Fixes: 977e5f8ed0ab ("afs: Split the usage count on struct afs_server") Signed-off-by: David Howells cc: Marc Dionne cc: Simon Horman cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20250218192250.296870-5-dhowells@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- fs/afs/server_list.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/afs/server_list.c b/fs/afs/server_list.c index 4d6369477f54e..89c75d934f79e 100644 --- a/fs/afs/server_list.c +++ b/fs/afs/server_list.c @@ -67,8 +67,8 @@ struct afs_server_list *afs_alloc_server_list(struct afs_volume *volume, break; if (j < slist->nr_servers) { if (slist->servers[j].server == server) { - afs_put_server(volume->cell->net, server, - afs_server_trace_put_slist_isort); + afs_unuse_server(volume->cell->net, server, + afs_server_trace_put_slist_isort); continue; } -- 2.39.5