Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755215AbaDNTCH (ORCPT ); Mon, 14 Apr 2014 15:02:07 -0400 Received: from g6t1526.atlanta.hp.com ([15.193.200.69]:24772 "EHLO g6t1526.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754255AbaDNTCE (ORCPT ); Mon, 14 Apr 2014 15:02:04 -0400 Date: Mon, 14 Apr 2014 14:01:09 -0500 From: scameron@beardog.cce.hp.com To: James Bottomley Cc: Bjorn Helgaas , Davidlohr Bueso , Baoquan He , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-pci@vger.kernel.org, Joerg Roedel , iommu@lists.linux-foundation.org, Jiang Liu , scameron@beardog.cce.hp.com Subject: [PATCH] hpsa: fix NULL dereference in hpsa_put_ctlr_into_performant_mode() Message-ID: <20140414190109.GD21686@beardog.cce.hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Initialize local variable trans_support before it is used rather than after. It is supposed to contain the value of a register on the controller containing bits that describe which transport modes the controller supports (e.g. "performant", "ioaccel1", "ioaccel2"). A NULL pointer dereference will almost certainly occur if trans_support is not initialized at the right point. If for example the uninitialized trans_support value does not have the bit set for ioaccel2 support when it should be, then ioaccel2_alloc_cmds_and_bft() will not get called as it should be and the h->ioaccel2_blockFetchTable array will remain NULL instead of being allocated. Too late, trans_support finally gets initialized with the correct value with ioaccel2 mode bit set, which later causes calc_bucket_map() to be called to fill in h->ioaccel2_blockFetchTable[]. However h->ioaccel2_blockFetchTable is NULL because it didn't get allocated because earlier trans_support wasn't initialized at the right point. Signed-off-by: Stephen M. Cameron --- drivers/scsi/hpsa.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c index 8cf4a0c..9a6e4a2 100644 --- a/drivers/scsi/hpsa.c +++ b/drivers/scsi/hpsa.c @@ -7463,6 +7463,10 @@ static void hpsa_put_ctlr_into_performant_mode(struct ctlr_info *h) if (hpsa_simple_mode) return; + trans_support = readl(&(h->cfgtable->TransportSupport)); + if (!(trans_support & PERFORMANT_MODE)) + return; + /* Check for I/O accelerator mode support */ if (trans_support & CFGTBL_Trans_io_accel1) { transMethod |= CFGTBL_Trans_io_accel1 | @@ -7479,10 +7483,6 @@ static void hpsa_put_ctlr_into_performant_mode(struct ctlr_info *h) } /* TODO, check that this next line h->nreply_queues is correct */ - trans_support = readl(&(h->cfgtable->TransportSupport)); - if (!(trans_support & PERFORMANT_MODE)) - return; - h->nreply_queues = h->msix_vector > 0 ? h->msix_vector : 1; hpsa_get_max_perf_mode_cmds(h); /* Performant mode ring buffer and supporting data structures */ -- 1.7.1 -- 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/