Commit 67c99a72 authored Apr 14, 2014 by scameron@beardog.cce.hp.com Committed by James Bottomley Apr 21, 2014

[SCSI] hpsa: fix NULL dereference in hpsa_put_ctlr_into_performant_mode()



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.

Fixes: e1f7de0c
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Reported-by: Baoquan He <bhe@redhat.com>
Tested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

parent c9eaa447

drivers/scsi/hpsa.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -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 */

Admin message