Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753270AbcDRKtx (ORCPT ); Mon, 18 Apr 2016 06:49:53 -0400 Received: from mail.kernel.org ([198.145.29.136]:34816 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753239AbcDRKtv (ORCPT ); Mon, 18 Apr 2016 06:49:51 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Guenter Roeck , Alexey Klimov , Mark Brown , Zefan Li Subject: [PATCH 3.4 51/92] spi: Fix documentation of spi_alloc_master() Date: Mon, 18 Apr 2016 18:45:56 +0800 Message-Id: <1460976397-5688-51-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1460976338-5631-1-git-send-email-lizf@kernel.org> References: <1460976338-5631-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1835 Lines: 50 From: Guenter Roeck 3.4.112-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit a394d635193b641f2c86ead5ada5b115d57c51f8 upstream. Actually, spi_master_put() after spi_alloc_master() must _not_ be followed by kfree(). The memory is already freed with the call to spi_master_put() through spi_master_class, which registers a release function. Calling both spi_master_put() and kfree() results in often nasty (and delayed) crashes elsewhere in the kernel, often in the networking stack. This reverts commit eb4af0f5349235df2e4a5057a72fc8962d00308a. Link to patch and concerns: https://lkml.org/lkml/2012/9/3/269 or http://lkml.iu.edu/hypermail/linux/kernel/1209.0/00790.html Alexey Klimov: This revert becomes valid after 94c69f765f1b4a658d96905ec59928e3e3e07e6a when spi-imx.c has been fixed and there is no need to call kfree() so comment for spi_alloc_master() should be fixed. Signed-off-by: Guenter Roeck Signed-off-by: Alexey Klimov Signed-off-by: Mark Brown Signed-off-by: Zefan Li --- drivers/spi/spi.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 3d8f662..a3f31e9 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -831,8 +831,7 @@ static struct class spi_master_class = { * * The caller is responsible for assigning the bus number and initializing * the master's methods before calling spi_register_master(); and (after errors - * adding the device) calling spi_master_put() and kfree() to prevent a memory - * leak. + * adding the device) calling spi_master_put() to prevent a memory leak. */ struct spi_master *spi_alloc_master(struct device *dev, unsigned size) { -- 1.9.1