From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from youngberry.canonical.com ([91.189.89.112]:49097 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754812AbbH0WNY (ORCPT ); Thu, 27 Aug 2015 18:13:24 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Tony Battersby , James Bottomley , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 109/130] scsi: fix memory leak with scsi-mq Date: Thu, 27 Aug 2015 15:11:40 -0700 Message-Id: <1440713521-5906-110-git-send-email-kamal@canonical.com> In-Reply-To: <1440713521-5906-1-git-send-email-kamal@canonical.com> References: <1440713521-5906-1-git-send-email-kamal@canonical.com> Sender: stable-owner@vger.kernel.org List-ID: 3.19.8-ckt6 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Tony Battersby commit 0c958ecc69c277b25f38f72bc6d18ab145e8167c upstream. Fix a memory leak with scsi-mq triggered by commands with large data transfer length. __sg_alloc_table() sets both table->nents and table->orig_nents to the same value. When the scatterlist is DMA-mapped, table->nents is overwritten with the (possibly smaller) size of the DMA-mapped scatterlist, while table->orig_nents retains the original size of the allocated scatterlist. scsi_free_sgtable() should therefore check orig_nents instead of nents, and all code that initializes sdb->table without calling __sg_alloc_table() should set both nents and orig_nents. Fixes: d285203cf647 ("scsi: add support for a blk-mq based I/O path.") Signed-off-by: Tony Battersby Reviewed-by: Christoph Hellwig Reviewed-by: Ewan D. Milne Signed-off-by: James Bottomley Signed-off-by: Kamal Mostafa --- drivers/scsi/scsi_error.c | 2 +- drivers/scsi/scsi_lib.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 8afb016..9e3d16f 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -950,7 +950,7 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses, scmd->sdb.length); scmd->sdb.table.sgl = &ses->sense_sgl; scmd->sc_data_direction = DMA_FROM_DEVICE; - scmd->sdb.table.nents = 1; + scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1; scmd->cmnd[0] = REQUEST_SENSE; scmd->cmnd[4] = scmd->sdb.length; scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]); diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 7129701..397644d 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -583,7 +583,7 @@ static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq) { - if (mq && sdb->table.nents <= SCSI_MAX_SG_SEGMENTS) + if (mq && sdb->table.orig_nents <= SCSI_MAX_SG_SEGMENTS) return; __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free); } @@ -597,8 +597,8 @@ static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq) if (mq) { if (nents <= SCSI_MAX_SG_SEGMENTS) { - sdb->table.nents = nents; - sg_init_table(sdb->table.sgl, sdb->table.nents); + sdb->table.nents = sdb->table.orig_nents = nents; + sg_init_table(sdb->table.sgl, nents); return 0; } first_chunk = sdb->table.sgl; -- 1.9.1