treewide: uapi: Replace zero-length arrays with flexible-array members

2022-06-28T19:26:05+00:00

There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. This code was transformed with the help of Coccinelle: (linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch) @@ identifier S, member, array; type T1, T2; @@ struct S { ... T1 member; T2 array[ - 0 ]; }; -fstrict-flex-arrays=3 is coming and we need to land these changes to prevent issues like these in the short future: ../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0, but the source string has length 2 (including NUL byte) [-Wfortify-source] strcpy(de3->name, "."); ^ Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If this breaks anything, we can use a union with a new member name. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/78 Build-tested-by: kernel test robot Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/ Acked-by: Dan Williams # For ndctl.h Signed-off-by: Gustavo A. R. Silva

selftests/bpf: missing headers test_lwt_seg6local

2018-05-28T15:41:00+00:00

Previous patch "selftests/bpf: test for seg6local End.BPF action" lacks some UAPI headers in tools/. clang -I. -I./include/uapi -I../../../include/uapi -idirafter /usr/local/include -idirafter /data/users/yhs/work/llvm/build/install/lib/clang/7.0.0/include -idirafter /usr/include -Wno-compare-distinct-pointer-types \ -O2 -target bpf -emit-llvm -c test_lwt_seg6local.c -o - | \ llc -march=bpf -mcpu=generic -filetype=obj -o [...]/net-next/tools/testing/selftests/bpf/test_lwt_seg6local.o test_lwt_seg6local.c:4:10: fatal error: 'linux/seg6_local.h' file not found ^~~~~~~~~~~~~~~~~~~~ 1 error generated. make: Leaving directory `/data/users/yhs/work/net-next/tools/testing/selftests/bpf' v2: moving the headers to tools/include/uapi/. Reported-by: Y Song Signed-off-by: Mathieu Xhonneux Signed-off-by: Daniel Borkmann

kernel/linux.git/tools/include/uapi/linux/seg6.h, branch v6.19.11

treewide: uapi: Replace zero-length arrays with flexible-array members

selftests/bpf: missing headers test_lwt_seg6local