On Thu, Aug 17, 2023 at 11:19:13AM -0600, Gustavo A. R. Silva wrote: > Change the notation from pointer-to-array to pointer-to-pointer. > With this, we avoid the compiler complaining about trying > to access a region of size zero as an argument during function > calls. > > This is a workaround to prevent the compiler complaining about > accessing an array of size zero when evaluating the arguments > of a couple of function calls. See below: > > kernel/cgroup/cgroup.c: In function 'find_css_set': > kernel/cgroup/cgroup.c:1206:16: warning: 'find_existing_css_set' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] > 1206 | cset = find_existing_css_set(old_cset, cgrp, template); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > kernel/cgroup/cgroup.c:1206:16: note: referencing argument 3 of type 'struct cgroup_subsys_state *[0]' > kernel/cgroup/cgroup.c:1071:24: note: in a call to function 'find_existing_css_set' > 1071 | static struct css_set *find_existing_css_set(struct css_set *old_cset, > | ^~~~~~~~~~~~~~~~~~~~~ > > With the change to pointer-to-pointer, the functions are not prevented > from being executed, and they will do what they have to do when > CGROUP_SUBSYS_COUNT == 0. > > Address the following -Wstringop-overflow warnings seen when > built with ARM architecture and aspeed_g4_defconfig configuration > (notice that under this configuration CGROUP_SUBSYS_COUNT == 0): > > kernel/cgroup/cgroup.c:1208:16: warning: 'find_existing_css_set' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] > kernel/cgroup/cgroup.c:1258:15: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] > kernel/cgroup/cgroup.c:6089:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] > kernel/cgroup/cgroup.c:6153:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] > > This results in no differences in binary output. > > Link: https://github.com/KSPP/linux/issues/316 > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> Applied to cgroup/for-6.6. Thanks. -- tejun
