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mm: shrinker: avoid memleak in alloc_shrinker_info

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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):
    [<ffffffff81372754>] __kmalloc_node_noprof+0x394/0x470
    [<ffffffff813024ab>] alloc_shrinker_info+0x7b/0x1a0
    [<ffffffff813b526a>] mem_cgroup_css_online+0x11a/0x3b0
    [<ffffffff81198dd9>] online_css+0x29/0xa0
    [<ffffffff811a243d>] cgroup_apply_control_enable+0x20d/0x360
    [<ffffffff811a5728>] cgroup_mkdir+0x168/0x5f0
    [<ffffffff8148543e>] kernfs_iop_mkdir+0x5e/0x90
    [<ffffffff813dbb24>] vfs_mkdir+0x144/0x220
    [<ffffffff813e1c97>] do_mkdirat+0x87/0x130
    [<ffffffff813e1de9>] __x64_sys_mkdir+0x49/0x70
    [<ffffffff81f8c928>] do_syscall_64+0x68/0x140
    [<ffffffff8200012f>] 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: 307bececcd ("mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred}")
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Wang Weiyang <wangweiyang2@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Chen Ridong 2024-10-25 06:09:42 +00:00 committed by Andrew Morton
parent 0173471d21
commit 15e8156713
1 changed files with 5 additions and 3 deletions
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8
mm/shrinker.c
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@ -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);