From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752115AbdCDDBM (ORCPT ); Fri, 3 Mar 2017 22:01:12 -0500 Received: from mail-pg0-f50.google.com ([74.125.83.50]:34359 "EHLO mail-pg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751560AbdCDDBL (ORCPT ); Fri, 3 Mar 2017 22:01:11 -0500 From: Tahsin Erdogan To: Johannes Weiner , Michal Hocko , Vladimir Davydov , cgroups@vger.kernel.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Tahsin Erdogan Subject: [PATCH] mm: do not call mem_cgroup_free() from within mem_cgroup_alloc() Date: Fri, 3 Mar 2017 18:53:56 -0800 Message-Id: <20170304025356.12265-1-tahsin@google.com> X-Mailer: git-send-email 2.12.0.rc1.440.g5b76565f74-goog Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org mem_cgroup_free() indirectly calls wb_domain_exit() which is not prepared to deal with a struct wb_domain object that hasn't executed wb_domain_init(). For instance, the following warning message is printed by lockdep if alloc_percpu() fails in mem_cgroup_alloc(): INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 1 PID: 1950 Comm: mkdir Not tainted 4.10.0+ #151 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x67/0x99 register_lock_class+0x36d/0x540 __lock_acquire+0x7f/0x1a30 ? irq_work_queue+0x73/0x90 ? wake_up_klogd+0x36/0x40 ? console_unlock+0x45d/0x540 ? vprintk_emit+0x211/0x2e0 lock_acquire+0xcc/0x200 ? try_to_del_timer_sync+0x60/0x60 del_timer_sync+0x3c/0xc0 ? try_to_del_timer_sync+0x60/0x60 wb_domain_exit+0x14/0x20 mem_cgroup_free+0x14/0x40 mem_cgroup_css_alloc+0x3f9/0x620 cgroup_apply_control_enable+0x190/0x390 cgroup_mkdir+0x290/0x3d0 kernfs_iop_mkdir+0x58/0x80 vfs_mkdir+0x10e/0x1a0 SyS_mkdirat+0xa8/0xd0 SyS_mkdir+0x14/0x20 entry_SYSCALL_64_fastpath+0x18/0xad Fix mem_cgroup_alloc() by doing more granular clean up in case of failures. Fixes: 0b8f73e104285 ("mm: memcontrol: clean up alloc, online, offline, free functions") Signed-off-by: Tahsin Erdogan --- mm/memcontrol.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c52ec893e241..9a9d5630df91 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4194,9 +4194,12 @@ static struct mem_cgroup *mem_cgroup_alloc(void) idr_replace(&mem_cgroup_idr, memcg, memcg->id.id); return memcg; fail: + for_each_node(node) + free_mem_cgroup_per_node_info(memcg, node); + free_percpu(memcg->stat); if (memcg->id.id > 0) idr_remove(&mem_cgroup_idr, memcg->id.id); - mem_cgroup_free(memcg); + kfree(memcg); return NULL; } -- 2.12.0.rc1.440.g5b76565f74-goog