From 4ddfb4af07c82e7f63c28347e463046aa14c1837 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Tue, 11 Feb 2020 17:10:45 -0600 Subject: [PATCH] firmware: arm_scmi: Replace zero-length array with flexible-array member The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertenly introduced[3] to the codebase from now on. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Replace the zero-length member "msg_payload" in scmi_shared_mem structure with flexible-array. Link: https://lore.kernel.org/r/20200211231045.GA13956@embeddedor Signed-off-by: Gustavo A. R. Silva [ rebased the change as files are moved around ] Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/firmware/arm_scmi/shmem.c b/drivers/firmware/arm_scmi/shmem.c index ca0ffd302ea2..e1e816e0018c 100644 --- a/drivers/firmware/arm_scmi/shmem.c +++ b/drivers/firmware/arm_scmi/shmem.c @@ -26,7 +26,7 @@ struct scmi_shared_mem { #define SCMI_SHMEM_FLAG_INTR_ENABLED BIT(0) __le32 length; __le32 msg_header; - u8 msg_payload[0]; + u8 msg_payload[]; }; void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem,