Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754625AbbHNR7F (ORCPT ); Fri, 14 Aug 2015 13:59:05 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51843 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933051AbbHNRxW (ORCPT ); Fri, 14 Aug 2015 13:53:22 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wen Xiong , Gabriel Krisman Bertazi , Brian King , "Martin K. Petersen" , James Bottomley Subject: [PATCH 3.14 08/44] ipr: Fix incorrect trace indexing Date: Fri, 14 Aug 2015 10:44:45 -0700 Message-Id: <20150814174401.877524105@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150814174401.628233291@linuxfoundation.org> References: <20150814174401.628233291@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2237 Lines: 58 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Brian King commit bb7c54339e6a10ecce5c4961adf5e75b3cf0af30 upstream. When ipr's internal driver trace was changed to an atomic, a signed/unsigned bug slipped in which results in us indexing backwards in our memory buffer writing on memory that does not belong to us. This patch fixes this by removing the modulo and instead just mask off the low bits. Tested-by: Wen Xiong Reviewed-by: Wen Xiong Reviewed-by: Gabriel Krisman Bertazi Signed-off-by: Brian King Reviewed-by: Martin K. Petersen Signed-off-by: James Bottomley Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/ipr.c | 5 +++-- drivers/scsi/ipr.h | 1 + 2 files changed, 4 insertions(+), 2 deletions(-) --- a/drivers/scsi/ipr.c +++ b/drivers/scsi/ipr.c @@ -592,9 +592,10 @@ static void ipr_trc_hook(struct ipr_cmnd { struct ipr_trace_entry *trace_entry; struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg; + unsigned int trace_index; - trace_entry = &ioa_cfg->trace[atomic_add_return - (1, &ioa_cfg->trace_index)%IPR_NUM_TRACE_ENTRIES]; + trace_index = atomic_add_return(1, &ioa_cfg->trace_index) & IPR_TRACE_INDEX_MASK; + trace_entry = &ioa_cfg->trace[trace_index]; trace_entry->time = jiffies; trace_entry->op_code = ipr_cmd->ioarcb.cmd_pkt.cdb[0]; trace_entry->type = type; --- a/drivers/scsi/ipr.h +++ b/drivers/scsi/ipr.h @@ -1459,6 +1459,7 @@ struct ipr_ioa_cfg { #define IPR_NUM_TRACE_INDEX_BITS 8 #define IPR_NUM_TRACE_ENTRIES (1 << IPR_NUM_TRACE_INDEX_BITS) +#define IPR_TRACE_INDEX_MASK (IPR_NUM_TRACE_ENTRIES - 1) #define IPR_TRACE_SIZE (sizeof(struct ipr_trace_entry) * IPR_NUM_TRACE_ENTRIES) char trace_start[8]; #define IPR_TRACE_START_LABEL "trace" -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/