From bef4a48f4ef798c4feddf045d49e53c8a97d5e37 Mon Sep 17 00:00:00 2001 From: Mark Hasemeyer Date: Tue, 7 Nov 2023 14:47:43 -0700 Subject: spi: Fix null dereference on suspend 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 Link: https://lore.kernel.org/r/20231107144743.v1.1.I7987f05f61901f567f7661763646cb7d7919b528@changeid Signed-off-by: Mark Brown Cc: stable@kernel.org --- include/linux/spi/spi.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 86825c88b576..255a0562aea5 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -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; -- cgit v1.2.3