4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
commit 046667c4d3196938e992fba0dfcde570aa85cd0e upstream.
we are *not* guaranteed that anything past the terminating NUL
is mapped (let alone initialized with anything sane).
Fixes: 0dea116876ee ("cgroup: implement eventfd-based generic API for notifications")
Cc: stable@xxxxxxxxxxxxxxx
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4140,9 +4140,12 @@ static ssize_t memcg_write_event_control
buf = endp + 1;
cfd = simple_strtoul(buf, &endp, 10);
- if ((*endp != ' ') && (*endp != '\0'))
+ if (*endp == '\0')
+ buf = endp;
+ else if (*endp == ' ')
+ buf = endp + 1;
+ else
return -EINVAL;
- buf = endp + 1;
event = kzalloc(sizeof(*event), GFP_KERNEL);
if (!event)
