[059/227] mm: memcontrol: fix cannot alloc the maximum memcg ID

Commit Message

Andrew Morton March 22, 2022, 9:41 p.m. UTC

From: Muchun Song <[e-mail]>
Subject: mm: memcontrol: fix cannot alloc the maximum memcg ID

The idr_alloc() does not include @max ID.  So in the current
implementation, the maximum memcg ID is 65534 instead of 65535.  It seems
a bug.  So fix this.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Muchun Song <[e-mail]>
Cc: Alex Shi <[e-mail]>
Cc: Anna Schumaker <[e-mail]>
Cc: Chao Yu <[e-mail]>
Cc: Dave Chinner <[e-mail]>
Cc: Fam Zheng <[e-mail]>
Cc: Jaegeuk Kim <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: Kari Argillander <[e-mail]>
Cc: Matthew Wilcox (Oracle) <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Qi Zheng <[e-mail]>
Cc: Roman Gushchin <[e-mail]>
Cc: Shakeel Butt <[e-mail]>
Cc: Theodore Ts'o <[e-mail]>
Cc: Trond Myklebust <[e-mail]>
Cc: Vladimir Davydov <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Wei Yang <[e-mail]>
Cc: Xiongchun Duan <[e-mail]>
Cc: Yang Shi <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/memcontrol.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Patch

--- a/mm/memcontrol.c~mm-memcontrol-fix-cannot-alloc-the-maximum-memcg-id
+++ a/mm/memcontrol.c
@@ -5088,8 +5088,7 @@  static struct mem_cgroup *mem_cgroup_all
 		return ERR_PTR(error);
 
 	memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
-				 1, MEM_CGROUP_ID_MAX,
-				 GFP_KERNEL);
+				 1, MEM_CGROUP_ID_MAX + 1, GFP_KERNEL);
 	if (memcg->id.id < 0) {
 		error = memcg->id.id;
 		goto fail;