@@ -3317,33 +3317,52 @@ void spi_unregister_controller(struct spi_controller *ctlr)
}
EXPORT_SYMBOL_GPL(spi_unregister_controller);
+static inline int __spi_check_suspended(const struct spi_controller *ctlr)
+{
+ return ctlr->flags & SPI_CONTROLLER_SUSPENDED ? -ESHUTDOWN : 0;
+}
+
+static inline void __spi_mark_suspended(struct spi_controller *ctlr)
+{
+ mutex_lock(&ctlr->bus_lock_mutex);
+ ctlr->flags |= SPI_CONTROLLER_SUSPENDED;
+ mutex_unlock(&ctlr->bus_lock_mutex);
+}
+
+static inline void __spi_mark_resumed(struct spi_controller *ctlr)
+{
+ mutex_lock(&ctlr->bus_lock_mutex);
+ ctlr->flags &= ~SPI_CONTROLLER_SUSPENDED;
+ mutex_unlock(&ctlr->bus_lock_mutex);
+}
+
int spi_controller_suspend(struct spi_controller *ctlr)
{
- int ret;
+ int ret = 0;
/* Basically no-ops for non-queued controllers */
- if (!ctlr->queued)
- return 0;
-
- ret = spi_stop_queue(ctlr);
- if (ret)
- dev_err(&ctlr->dev, "queue stop failed\n");
+ if (ctlr->queued) {
+ ret = spi_stop_queue(ctlr);
+ if (ret)
+ dev_err(&ctlr->dev, "queue stop failed\n");
+ }
+ __spi_mark_suspended(ctlr);
return ret;
}
EXPORT_SYMBOL_GPL(spi_controller_suspend);
int spi_controller_resume(struct spi_controller *ctlr)
{
- int ret;
-
- if (!ctlr->queued)
- return 0;
+ int ret = 0;
- ret = spi_start_queue(ctlr);
- if (ret)
- dev_err(&ctlr->dev, "queue restart failed\n");
+ __spi_mark_resumed(ctlr);
+ if (ctlr->queued) {
+ ret = spi_start_queue(ctlr);
+ if (ret)
+ dev_err(&ctlr->dev, "queue restart failed\n");
+ }
return ret;
}
EXPORT_SYMBOL_GPL(spi_controller_resume);
@@ -4147,8 +4166,7 @@ static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct s
ctlr->cur_msg = msg;
ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
if (ret)
- goto out;
-
+ dev_err(&ctlr->dev, "noqueue transfer failed\n");
ctlr->cur_msg = NULL;
ctlr->fallback = false;
@@ -4164,7 +4182,6 @@ static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct s
spi_idle_runtime_pm(ctlr);
}
-out:
mutex_unlock(&ctlr->io_mutex);
}
@@ -4187,6 +4204,11 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message)
int status;
struct spi_controller *ctlr = spi->controller;
+ if (__spi_check_suspended(ctlr)) {
+ dev_warn_once(&spi->dev, "Attempted to sync while suspend\n");
+ return -ESHUTDOWN;
+ }
+
status = __spi_validate(spi, message);
if (status != 0)
return status;
@@ -566,6 +566,7 @@ struct spi_controller {
#define SPI_CONTROLLER_MUST_RX BIT(3) /* Requires rx */
#define SPI_CONTROLLER_MUST_TX BIT(4) /* Requires tx */
#define SPI_CONTROLLER_GPIO_SS BIT(5) /* GPIO CS must select slave */
+#define SPI_CONTROLLER_SUSPENDED BIT(6) /* Currently suspended */
/* Flag indicating if the allocation of this struct is devres-managed */
bool devm_allocated;
A race condition exists where a synchronous (noqueue) transfer can be active during a system suspend. This can cause a null pointer dereference exception to occur when the system resumes. Example order of events leading to the exception: 1. spi_sync() calls __spi_transfer_message_noqueue() which sets ctlr->cur_msg 2. Spi transfer begins via spi_transfer_one_message() 3. System is suspended interrupting the transfer context 4. System is resumed 6. spi_controller_resume() calls spi_start_queue() which resets cur_msg to NULL 7. Spi transfer context resumes and spi_finalize_current_message() is called which dereferences cur_msg (which is now NULL) Wait for synchronous transfers to complete before suspending by acquiring the bus mutex and setting/checking a suspend flag. Signed-off-by: Mark Hasemeyer <markhas@chromium.org> --- drivers/spi/spi.c | 56 ++++++++++++++++++++++++++++------------- include/linux/spi/spi.h | 1 + 2 files changed, 40 insertions(+), 17 deletions(-)