From 15e8156713cc38031642fafc8baf7d53f19f2e83 Mon Sep 17 00:00:00 2001 From: Chen Ridong Date: Fri, 25 Oct 2024 06:09:42 +0000 Subject: [PATCH] mm: shrinker: avoid memleak in alloc_shrinker_info A memleak was found as below: unreferenced object 0xffff8881010d2a80 (size 32): comm "mkdir", pid 1559, jiffies 4294932666 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 @............... backtrace (crc 2e7ef6fa): [] __kmalloc_node_noprof+0x394/0x470 [] alloc_shrinker_info+0x7b/0x1a0 [] mem_cgroup_css_online+0x11a/0x3b0 [] online_css+0x29/0xa0 [] cgroup_apply_control_enable+0x20d/0x360 [] cgroup_mkdir+0x168/0x5f0 [] kernfs_iop_mkdir+0x5e/0x90 [] vfs_mkdir+0x144/0x220 [] do_mkdirat+0x87/0x130 [] __x64_sys_mkdir+0x49/0x70 [] do_syscall_64+0x68/0x140 [] entry_SYSCALL_64_after_hwframe+0x76/0x7e alloc_shrinker_info(), when shrinker_unit_alloc() returns an errer, the info won't be freed. Just fix it. Link: https://lkml.kernel.org/r/20241025060942.1049263-1-chenridong@huaweicloud.com Fixes: 307bececcd12 ("mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred}") Signed-off-by: Chen Ridong Acked-by: Qi Zheng Acked-by: Roman Gushchin Acked-by: Vlastimil Babka Acked-by: Kirill A. Shutemov Reviewed-by: Dave Chinner Cc: Anshuman Khandual Cc: Muchun Song Cc: Wang Weiyang Cc: Signed-off-by: Andrew Morton --- mm/shrinker.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/mm/shrinker.c b/mm/shrinker.c index dc5d2a6fcfc4..4a93fd433689 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -76,19 +76,21 @@ void free_shrinker_info(struct mem_cgroup *memcg) int alloc_shrinker_info(struct mem_cgroup *memcg) { - struct shrinker_info *info; int nid, ret = 0; int array_size = 0; mutex_lock(&shrinker_mutex); array_size = shrinker_unit_size(shrinker_nr_max); for_each_node(nid) { - info = kvzalloc_node(sizeof(*info) + array_size, GFP_KERNEL, nid); + struct shrinker_info *info = kvzalloc_node(sizeof(*info) + array_size, + GFP_KERNEL, nid); if (!info) goto err; info->map_nr_max = shrinker_nr_max; - if (shrinker_unit_alloc(info, NULL, nid)) + if (shrinker_unit_alloc(info, NULL, nid)) { + kvfree(info); goto err; + } rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); } mutex_unlock(&shrinker_mutex);