The patch titled
Subject: mm: shrinker: avoid memleak in alloc_shrinker_info
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-shrinker-avoid-memleak-in-alloc_shrinker_info.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shrinker-avoid-memleak-in-alloc_shrinker_info.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Chen Ridong <chenridong@xxxxxxxxxx>
Subject: mm: shrinker: avoid memleak in alloc_shrinker_info
Date: Fri, 25 Oct 2024 06:09:42 +0000
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@xxxxxxxxxxxxxxx
Fixes: 307bececcd12 ("mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred}")
Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
Acked-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Wang Weiyang <wangweiyang2@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shrinker.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/mm/shrinker.c~mm-shrinker-avoid-memleak-in-alloc_shrinker_info
+++ a/mm/shrinker.c
@@ -76,19 +76,21 @@ void free_shrinker_info(struct mem_cgrou
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);
_
Patches currently in -mm which might be from chenridong@xxxxxxxxxx are
mm-shrinker-avoid-memleak-in-alloc_shrinker_info.patch
