__setup() handlers should return 1 if the command line option is handled
and 0 if not (or maybe never return 0; it just pollutes init's environment).
The only reason that this particular __setup handler does not pollute
init's environment is that the setup string contains a '.', as in
"cgroup.memory". This causes init/main.c::unknown_boottoption() to
consider it to be an "Unused module parameter" and ignore it. (This is
for parsing of loadable module parameters any time after kernel init.)
Otherwise the string "cgroup.memory=whatever" would be added to init's
environment strings.
Instead of relying on this '.' quirk, just return 1 to indicate that
the boot option has been handled.
Note that there is no warning message if someone enters:
cgroup.memory=anything_invalid
Fixes: f7e1cb6ec51b0 ("mm: memcontrol: account socket memory in unified hierarchy memory controller")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Reported-by: Igor Zhbanov <i.zhbanov@xxxxxxxxxxxx>
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@xxxxxxxxxxxx
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: cgroups@xxxxxxxxxxxxxxx
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- linux-next-20220217.orig/mm/memcontrol.c
+++ linux-next-20220217/mm/memcontrol.c
@@ -7044,7 +7044,7 @@ static int __init cgroup_memory(char *s)
if (!strcmp(token, "nokmem"))
cgroup_memory_nokmem = true;
}
- return 0;
+ return 1;
}
__setup("cgroup.memory=", cgroup_memory);
