spi: spi-mem: check if data buffers are on stack

The buffers passed in the data phase must be DMA-able. Programmers often don't realise this requirement and pass in buffers that reside on the stack. This can be hard to spot when reviewing code. Reject ops if their data buffer is on the stack to avoid this. Signed-off-by: Pratyush Yadav <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Mark Brown <[email protected]>
sedwards · Apr 21, 2022 · 8868c03 · 8868c03
1 parent 8c235cc
commit 8868c03
Showing 1 changed file with 10 additions and 0 deletions.
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
@@ -10,6 +10,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/spi-mem.h>
+#include <linux/sched/task_stack.h>
 
 #include "internals.h"
 
@@ -211,6 +212,15 @@ static int spi_mem_check_op(const struct spi_mem_op *op)
 	    !spi_mem_buswidth_is_valid(op->data.buswidth))
 		return -EINVAL;
 
+	/* Buffers must be DMA-able. */
+	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_IN &&
+			 object_is_on_stack(op->data.buf.in)))
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_OUT &&
+			 object_is_on_stack(op->data.buf.out)))
+		return -EINVAL;
+
 	return 0;
 }