[PATCH 5.6 15/23] staging: wfx: fix init/remove vs IRQ race

Greg Kroah-Hartman
2020-03-31T09:01:14Z

From: Michał Mirosław <mirq-linux@rere.qmqm.pl>

commit 4033714d6cbe04893aa0708d1fcaa45dd8eb3f53 upstream.

Current code races in init/exit with interrupt handlers. This is noticed
by the warning below. Fix it by using devres for ordering allocations and
IRQ de/registration.

WARNING: CPU: 0 PID: 827 at drivers/staging/wfx/bus_spi.c:142 wfx_spi_irq_handler+0x5c/0x64 [wfx]
race condition in driver init/deinit

Cc: stable@vger.kernel.org
Fixes: 0096214a59a7 ("staging: wfx: add support for I/O access")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/f0c66cbb3110c2736cd4357c753fba8c14ee3aee.1581416843.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/staging/wfx/bus_sdio.c | 15 ++++++---------
drivers/staging/wfx/bus_spi.c | 27 ++++++++++++++-------------
drivers/staging/wfx/main.c | 21 +++++++++++++--------
drivers/staging/wfx/main.h | 1 -
4 files changed, 33 insertions(+), 31 deletions(-)

--- a/drivers/staging/wfx/bus_sdio.c
+++ b/drivers/staging/wfx/bus_sdio.c
@@ -200,25 +200,23 @@ static int wfx_sdio_probe(struct sdio_fu
if (ret)
goto err0;

- ret = wfx_sdio_irq_subscribe(bus);
- if (ret)
- goto err1;
-
bus->core = wfx_init_common(&func->dev, &wfx_sdio_pdata,
&wfx_sdio_hwbus_ops, bus);
if (!bus->core) {
ret = -EIO;
- goto err2;
+ goto err1;
}

+ ret = wfx_sdio_irq_subscribe(bus);
+ if (ret)
+ goto err1;
+
ret = wfx_probe(bus->core);
if (ret)
- goto err3;
+ goto err2;

return 0;

-err3:
- wfx_free_common(bus->core);
err2:
wfx_sdio_irq_unsubscribe(bus);
err1:
@@ -234,7 +232,6 @@ static void wfx_sdio_remove(struct sdio_
struct wfx_sdio_priv *bus = sdio_get_drvdata(func);

wfx_release(bus->core);
- wfx_free_common(bus->core);
wfx_sdio_irq_unsubscribe(bus);
sdio_claim_host(func);
sdio_disable_func(func);
--- a/drivers/staging/wfx/bus_spi.c
+++ b/drivers/staging/wfx/bus_spi.c
@@ -156,6 +156,11 @@ static void wfx_spi_request_rx(struct wo
wfx_bh_request_rx(bus->core);
}

+static void wfx_flush_irq_work(void *w)
+{
+ flush_work(w);
+}
+
static size_t wfx_spi_align_size(void *priv, size_t size)
{
// Most of SPI controllers avoid DMA if buffer size is not 32bit aligned
@@ -211,22 +216,23 @@ static int wfx_spi_probe(struct spi_devi
udelay(2000);
}

- ret = devm_request_irq(&func->dev, func->irq, wfx_spi_irq_handler,
- IRQF_TRIGGER_RISING, "wfx", bus);
- if (ret)
- return ret;
-
INIT_WORK(&bus->request_rx, wfx_spi_request_rx);
bus->core = wfx_init_common(&func->dev, &wfx_spi_pdata,
&wfx_spi_hwbus_ops, bus);
if (!bus->core)
return -EIO;

- ret = wfx_probe(bus->core);
+ ret = devm_add_action_or_reset(&func->dev, wfx_flush_irq_work,
+ &bus->request_rx);
if (ret)
- wfx_free_common(bus->core);
+ return ret;
+
+ ret = devm_request_irq(&func->dev, func->irq, wfx_spi_irq_handler,
+ IRQF_TRIGGER_RISING, "wfx", bus);
+ if (ret)
+ return ret;

- return ret;
+ return wfx_probe(bus->core);
}

static int wfx_spi_remove(struct spi_device *func)
@@ -234,11 +240,6 @@ static int wfx_spi_remove(struct spi_dev
struct wfx_spi_priv *bus = spi_get_drvdata(func);

wfx_release(bus->core);
- wfx_free_common(bus->core);
- // A few IRQ will be sent during device release. Hopefully, no IRQ
- // should happen after wdev/wvif are released.
- devm_free_irq(&func->dev, func->irq, bus);
- flush_work(&bus->request_rx);
return 0;
}

--- a/drivers/staging/wfx/main.c
+++ b/drivers/staging/wfx/main.c
@@ -262,6 +262,16 @@ static int wfx_send_pdata_pds(struct wfx
return ret;
}

+static void wfx_free_common(void *data)
+{
+ struct wfx_dev *wdev = data;
+
+ mutex_destroy(&wdev->rx_stats_lock);
+ mutex_destroy(&wdev->conf_mutex);
+ wfx_tx_queues_deinit(wdev);
+ ieee80211_free_hw(wdev->hw);
+}
+
struct wfx_dev *wfx_init_common(struct device *dev,
const struct wfx_platform_data *pdata,
const struct hwbus_ops *hwbus_ops,
@@ -332,15 +342,10 @@ struct wfx_dev *wfx_init_common(struct d
wfx_init_hif_cmd(&wdev->hif_cmd);
wfx_tx_queues_init(wdev);

- return wdev;
-}
+ if (devm_add_action_or_reset(dev, wfx_free_common, wdev))
+ return NULL;

-void wfx_free_common(struct wfx_dev *wdev)
-{
- mutex_destroy(&wdev->rx_stats_lock);
- mutex_destroy(&wdev->conf_mutex);
- wfx_tx_queues_deinit(wdev);
- ieee80211_free_hw(wdev->hw);
+ return wdev;
}

int wfx_probe(struct wfx_dev *wdev)
--- a/drivers/staging/wfx/main.h
+++ b/drivers/staging/wfx/main.h
@@ -34,7 +34,6 @@ struct wfx_dev *wfx_init_common(struct d
const struct wfx_platform_data *pdata,
const struct hwbus_ops *hwbus_ops,
void *hwbus_priv);
-void wfx_free_common(struct wfx_dev *wdev);

int wfx_probe(struct wfx_dev *wdev);
void wfx_release(struct wfx_dev *wdev);