From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:36080 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752328AbeCWJ7Q (ORCPT ); Fri, 23 Mar 2018 05:59:16 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Gary R Hook , PrasannaKumar Muralidharan , Herbert Xu , Sasha Levin Subject: [PATCH 4.15 75/84] hwrng: core - Clean up RNG list when last hwrng is unregistered Date: Fri, 23 Mar 2018 10:54:29 +0100 Message-Id: <20180323095423.243279414@linuxfoundation.org> In-Reply-To: <20180323095411.913234798@linuxfoundation.org> References: <20180323095411.913234798@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gary R Hook [ Upstream commit 0e4b52942b1c76f89e0dcb829f72e123d0678f54 ] Commit 142a27f0a731 added support for a "best" RNG, and in doing so introduced a hang from rmmod/modprobe -r when the last RNG on the list was unloaded. When the hwrng list is depleted, return the global variables to their original state and decrement all references to the object. Fixes: 142a27f0a731 ("hwrng: core - Reset user selected rng by writing "" to rng_current") Signed-off-by: Gary R Hook Reviewed-by: PrasannaKumar Muralidharan Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/char/hw_random/core.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -306,6 +306,10 @@ static int enable_best_rng(void) ret = ((new_rng == current_rng) ? 0 : set_current_rng(new_rng)); if (!ret) cur_rng_set_by_user = 0; + } else { + drop_current_rng(); + cur_rng_set_by_user = 0; + ret = 0; } return ret;