On 2024/10/12 10:42, Muchun Song wrote:
On Oct 11, 2024, at 22:21, Chen Ridong <chenridong@xxxxxxxxxxxxxxx> wrote: From: Chen Ridong <chenridong@xxxxxxxxxx> A memleak was found as bellow: 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 In the alloc_shrinker_info function, when shrinker_unit_alloc return err, the info won't be freed. Just fix it. Fixes: 307bececcd12 ("mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred}") Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx> --- mm/shrinker.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/shrinker.c b/mm/shrinker.c index dc5d2a6fcfc4..e4b795ee6d2e 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -87,8 +87,10 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) 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;Since we already use goto to do the cleanup for failure, I don't like to mix two different ways to do the similar thing. I suggest adding the kvfree (BTW, it could handle NULL argument) to the label of err. Muchun, Thanks.
Thanks, I will update soon. Best regards, Ridong
+ } rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); } mutex_unlock(&shrinker_mutex); -- 2.34.1
