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From:   Nicholas Mc Guire <hofrat@osadl.org>
To:     Eric Anholt <eric@anholt.net>
Cc:     Stefan Wahren <stefan.wahren@i2se.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dominic Braun <inf.braun@fau.de>,
        Tobias Buettner <tobias.buettner@fau.de>,
        Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Phil Elwell <phil@raspberrypi.org>,
        linux-rpi-kernel@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org, Nicholas Mc Guire <hofrat@osadl.org>
Subject: [PATCH RFC] staging: vc04_services: handle kzalloc failure
Date:   Thu, 18 Apr 2019 12:29:44 +0200
Message-Id: <1555583384-15670-1-git-send-email-hofrat@osadl.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The kzalloc here was being used without checking the return - if the
kzalloc fails return VCHIQ_ERROR. The call-site of
vchiq_platform_init_state() vchiq_init_state() was not responding
to an allocation failure so checks for != VCHIQ_SUCCESS
and pass VCHIQ_ERROR up to vchiq_platform_init() which then
will fail with -EINVAL.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
---

Problem located with experimental coccinelle script

Patch was compile-tested with: bcm2835_defconfig (implies BCM2835_VCHIQ=m)
(with sparse warning:
  CHECK   drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:410:29: warning: incorrect type in argument 1 (different address spaces)
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:410:29:    expected void const *x
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:410:29:    got char [noderef] <asn:1> *buf
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:416:63: warning: incorrect type in argument 1 (different address spaces)
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:416:63:    expected void const *addr
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:416:63:    got char [noderef] <asn:1> *
  CC [M]  drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.o
Q: should this buf have been remapped to user space e.g. remap_vmalloc_range ?

Patch is against 5.1-rc5 (localversion next is 20190417)

 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 3 +++
 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c     | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
index 31eb7d5..a9a2291 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
@@ -179,6 +179,9 @@ vchiq_platform_init_state(struct vchiq_state *state)
 	struct vchiq_2835_state *platform_state;
 
 	state->platform_state = kzalloc(sizeof(*platform_state), GFP_KERNEL);
+	if (!state->platform_state)
+		return VCHIQ_ERROR;
+
 	platform_state = (struct vchiq_2835_state *)state->platform_state;
 
 	platform_state->inited = 1;
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
index 6057a90..92e6221 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
@@ -2209,6 +2209,8 @@ vchiq_init_state(struct vchiq_state *state, struct vchiq_slot_zero *slot_zero)
 	local->debug[DEBUG_ENTRIES] = DEBUG_MAX;
 
 	status = vchiq_platform_init_state(state);
+	if (status != VCHIQ_SUCCES)
+		return VCHIQ_ERROR;
 
 	/*
 		bring up slot handler thread
-- 
2.1.4