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 C2D023398C for ; Mon, 9 Oct 2023 13:34:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PaWCSjFJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FCC2C433C8; Mon, 9 Oct 2023 13:34:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696858493; bh=L5fmVLqaKT9YPjq1vUzROWP4gFnrmQXKt7tiWIc9hTU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PaWCSjFJYIoNVMf+ywo+icVSPe9KhdLvxLonl8qhffnWJyYZtdrP6nXxgk5napDBM uyfLxRkk6zSEQ3aeNAvX78SvZKdKl6v65RPlnuKoVCY60C3Ia0HRStABBHcdnqE+rc OoERRwnrUekf/rxBNHiyPyP6BTGKUZobIvoGkf5Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Trond Myklebust Subject: [PATCH 5.4 130/131] NFS: Fix a race in __nfs_list_for_each_server() Date: Mon, 9 Oct 2023 15:02:50 +0200 Message-ID: <20231009130120.395908438@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130116.329529591@linuxfoundation.org> References: <20231009130116.329529591@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Trond Myklebust commit 9c07b75b80eeff714420fb6a4c880b284e529d0f upstream. The struct nfs_server gets put on the cl_superblocks list before the server->super field has been initialised, in which case the call to nfs_sb_active() will Oops. Add a check to ensure that we skip such a list entry. Fixes: 3c9e502b59fb ("NFS: Add a helper nfs_client_for_each_server()") Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- fs/nfs/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -445,7 +445,7 @@ static int __nfs_list_for_each_server(st rcu_read_lock(); list_for_each_entry_rcu(server, head, client_link) { - if (!nfs_sb_active(server->super)) + if (!(server->super && nfs_sb_active(server->super))) continue; rcu_read_unlock(); if (last)