2016-12-23 15:02:38

by Heinrich Schuchardt

[permalink] [raw]
Subject: [PATCH 1/1] MMC: meson: avoid possible NULL dereference

No actual segmentation faults were observed but the coding is
at least inconsistent.

irqreturn_t meson_mmc_irq():

We should not dereference host before checking it.

meson_mmc_irq_thread():

If cmd or mrq are NULL we should not dereference them after
writing a warning.

Fixes: 51c5d8447bd7 MMC: meson: initial support for GX platforms
Signed-off-by: Heinrich Schuchardt <[email protected]>
---
drivers/mmc/host/meson-gx-mmc.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index b352760c041e..09739352834c 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -578,13 +578,15 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
{
struct meson_host *host = dev_id;
struct mmc_request *mrq;
- struct mmc_command *cmd = host->cmd;
+ struct mmc_command *cmd;
u32 irq_en, status, raw_status;
irqreturn_t ret = IRQ_HANDLED;

if (WARN_ON(!host))
return IRQ_NONE;

+ cmd = host->cmd;
+
mrq = host->mrq;

if (WARN_ON(!mrq))
@@ -670,10 +672,10 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
int ret = IRQ_HANDLED;

if (WARN_ON(!mrq))
- ret = IRQ_NONE;
+ return IRQ_NONE;

if (WARN_ON(!cmd))
- ret = IRQ_NONE;
+ return IRQ_NONE;

data = cmd->data;
if (data) {
--
2.11.0