Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751974AbdC0HcM (ORCPT ); Mon, 27 Mar 2017 03:32:12 -0400 Received: from wolverine01.qualcomm.com ([199.106.114.254]:39377 "EHLO wolverine01.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751796AbdC0HcC (ORCPT ); Mon, 27 Mar 2017 03:32:02 -0400 X-IronPort-AV: E=Sophos;i="5.36,229,1486454400"; d="scan'208";a="272958675" X-IronPort-AV: E=McAfee;i="5800,7501,8479"; a="1386063305" X-MGA-submission: =?us-ascii?q?MDH17OXsJQsM0Y2U9IPYmBd4dnjt/K9y8xXtlB?= =?us-ascii?q?R8y1hTofdGGzzJd0j9Z8YQpoWGYI+1FyE7gg2OcDI1Qi1RijVS3olNhG?= =?us-ascii?q?RTN0LiGqX+eRY6py0kGYPIYbZ6P0Du20B3VdW1uKS7AEg8XO4L3DBmea?= =?us-ascii?q?iG?= From: Joeseph Chang To: joechang@codeaurora.org, minyard@acm.org, openipmi-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org Cc: anjiandi@codeaurora.org Subject: [PATCH v2] ipmi: Fix kernel panic at ipmi_ssif_thread() Date: Mon, 27 Mar 2017 01:31:42 -0600 Message-Id: <1490599902-45215-1-git-send-email-joechang@qti.qualcomm.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2491 Lines: 72 From: Joeseph Chang Since patch v1 touch ssif_info->multi_pos and ssif_info->multi_data after ssif_i2c_send(). msg_written_handler can be called at any time after ssif_i2c_send(). There is possible to have concurrent access to ssif_info->multi_pos or ssif_info->multi_data at msg_written_handler. Revert patch v1 and add new local pointer "i2c_data" which point to i2c data and size that will be sent out to avoid concurrent access in msg_written_handler(). Signed-off-by: Joeseph Chang --- drivers/char/ipmi/ipmi_ssif.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c index 39346ee..f36f018 100644 --- a/drivers/char/ipmi/ipmi_ssif.c +++ b/drivers/char/ipmi/ipmi_ssif.c @@ -852,6 +852,7 @@ static void msg_written_handler(struct ssif_info *ssif_info, int result, unsigned char *data, unsigned int len) { int rv; + unsigned char *i2c_data; /* We are single-threaded here, so no need for a lock. */ if (result < 0) { @@ -899,13 +900,22 @@ static void msg_written_handler(struct ssif_info *ssif_info, int result, left = 32; /* Length byte. */ ssif_info->multi_data[ssif_info->multi_pos] = left; + i2c_data = ssif_info->multi_data + ssif_info->multi_pos; + ssif_info->multi_pos += left; + if (left < 32) + /* + * Write is finished. Note that we must end + * with a write of less than 32 bytes to + * complete the transaction, even if it is + * zero bytes. + */ + ssif_info->multi_data = NULL; rv = ssif_i2c_send(ssif_info, msg_written_handler, I2C_SMBUS_WRITE, SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE, - ssif_info->multi_data + ssif_info->multi_pos, + i2c_data, I2C_SMBUS_BLOCK_DATA); - if (rv < 0) { /* request failed, just return the error. */ ssif_inc_stat(ssif_info, send_errors); @@ -914,16 +924,6 @@ static void msg_written_handler(struct ssif_info *ssif_info, int result, pr_info("Error from i2c_non_blocking_op(3)\n"); msg_done_handler(ssif_info, -EIO, NULL, 0); } - - ssif_info->multi_pos += left; - if (left < 32) - /* - * Write is finished. Note that we must end - * with a write of less than 32 bytes to - * complete the transaction, even if it is - * zero bytes. - */ - ssif_info->multi_data = NULL; } else { /* Ready to request the result. */ unsigned long oflags, *flags; -- 1.9.1