[PATCH V2] staging: vc04_services: handle kzalloc failure

[Nicholas Mc Guire]

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@xxxxxxxxx>
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
---

Problem located with experimental coccinelle script

V2: The != VCHIQ_SUCCES went unnoticed not clear how I did that as
    building drivers/staging/vc04_services/vchiq.o seemed to have succeeded
    anyway kbuild test found it. This is one of the disadvantages if one
    can not make path/file.o due to missing Makefiles and is required to
    build entire directories for compile-testing, I suspect that I did not
    clean the directory before compile-testing the patch.
    

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_SUCCESS)
+		return VCHIQ_ERROR;
 
 	/*
 		bring up slot handler thread
-- 
2.1.4