From: Gustavo A. R. Silva Date: Thu, 19 Mar 2020 22:21:05 +0000 (+0100) Subject: media: venus: hfi_cmds.h: Replace zero-length array with flexible-array member X-Git-Tag: v5.8-rc1~10^2~502 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=380f3bbd9562dc93be2e3cadc329b15284fbedae;p=linux-block.git media: venus: hfi_cmds.h: 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 inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] 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") Signed-off-by: Gustavo A. R. Silva Signed-off-by: Stanimir Varbanov Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/platform/qcom/venus/hfi_cmds.h b/drivers/media/platform/qcom/venus/hfi_cmds.h index cae9d5d61c0c..83705e237f1c 100644 --- a/drivers/media/platform/qcom/venus/hfi_cmds.h +++ b/drivers/media/platform/qcom/venus/hfi_cmds.h @@ -107,7 +107,7 @@ struct hfi_session_abort_pkt { struct hfi_session_set_property_pkt { struct hfi_session_hdr_pkt shdr; u32 num_properties; - u32 data[0]; + u32 data[]; }; struct hfi_session_set_buffers_pkt {