Dan Williams
2022-Jun-27 22:31 UTC
[PATCH][next] treewide: uapi: Replace zero-length arrays with flexible-array members
Gustavo A. R. Silva wrote:> 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: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp at intel.com/ > Signed-off-by: Gustavo A. R. Silva <gustavoars at kernel.org> > --- > Hi all! > > JFYI: I'm adding this to my -next tree. :) >[..]> include/uapi/linux/ndctl.h | 10 +--For ndctl.h Acked-by: Dan Williams <dan.j.williams at intel.com>