From nobody Thu Dec 18 00:09:50 2025 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BED741E5708; Tue, 17 Dec 2024 12:28:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734438515; cv=none; b=lp32YfWeTc+y/x1nWcgCJTPu6/he67CJ3tPoYQLQFMQh8oelpM3k9Dza4NMSCwMhyZCoG4BjQ5NvXSI4LC50XzjnsutELiYqdFMU+niF+Q4gt2N4vqRbZeDbu43lYleGv+qnB2VzR+UcUuBJpOjFsvBJ8ivV/slTN88fdtr8ccA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734438515; c=relaxed/simple; bh=CHfOmaBZQdUOxtMJsOYujGK+LwClFGhBqbS1tursMms=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=l4X/twQgsPzk8MI03khTetDVawLZnDn8Z1rWrF29G8NYU8TXymQ9UVCKUSDd9zw75Z57TBvHxUb6cXJVwrWBg2cUHkNIWcZfKZyeDXv6vMDAoHY1rvpskcM4NlDLFb2Zs7V49gtdmvOekK6+5NRbJJ+vmni/pbs1szqa/U+QKrY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4YCGLQ1rNbz4f3jqb; Tue, 17 Dec 2024 20:28:14 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id A65971A018C; Tue, 17 Dec 2024 20:28:28 +0800 (CST) Received: from hulk-vt.huawei.com (unknown [10.67.174.121]) by APP4 (Coremail) with SMTP id gCh0CgAX8oVebmFn4SNwEw--.64435S2; Tue, 17 Dec 2024 20:28:28 +0800 (CST) From: Chen Ridong To: akpm@linux-foundation.org, mhocko@kernel.org, hannes@cmpxchg.org, yosryahmed@google.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, davidf@vimeo.com, vbabka@suse.cz, handai.szj@taobao.com, rientjes@google.com, kamezawa.hiroyu@jp.fujitsu.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, chenridong@huawei.com, wangweiyang2@huawei.com Subject: [PATCH v1] memcg: fix soft lockup in the OOM process Date: Tue, 17 Dec 2024 12:18:28 +0000 Message-Id: <20241217121828.3219752-1-chenridong@huaweicloud.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgAX8oVebmFn4SNwEw--.64435S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Cr1fGF43CFWUXrW3Gr43Awb_yoW8KF45p3 ZrJFWUGw4rJr15Xr1xAr1Fgr15Ja17Aa1UXrsFvr1rJF17G3WUAry7JrWUtr1kGr4fZFy3 tFn0qw48tr1DZaUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvFb4IE77IF4wAFF20E14v26ryj6rWUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Cr0_Gr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I 0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40E x7xfMcIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x 0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAa w2AFwI0_GFv_Wryl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxV Aqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a 6rW5MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6x kF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AK xVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvj xUxo7KDUUUU X-CM-SenderInfo: hfkh02xlgr0w46kxt4xhlfz01xgou0bp/ Content-Type: text/plain; charset="utf-8" From: Chen Ridong A soft lockup issue was found in the product with. About 56,000 tasks were in the OOM cgroup, it was traversing them when the soft lockup was triggered. watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [VM Thread:1503066] CPU: 2 PID: 1503066 Comm: VM Thread Kdump: loaded Tainted: G Hardware name: Huawei Cloud OpenStack Nova, BIOS RIP: 0010:console_unlock+0x343/0x540 RSP: 0000:ffffb751447db9a0 EFLAGS: 00000247 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000247 RBP: ffffffffafc71f90 R08: 0000000000000000 R09: 0000000000000040 R10: 0000000000000080 R11: 0000000000000000 R12: ffffffffafc74bd0 R13: ffffffffaf60a220 R14: 0000000000000247 R15: 0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2fe6ad91f0 CR3: 00000004b2076003 CR4: 0000000000360ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vprintk_emit+0x193/0x280 printk+0x52/0x6e dump_task+0x114/0x130 mem_cgroup_scan_tasks+0x76/0x100 dump_header+0x1fe/0x210 oom_kill_process+0xd1/0x100 out_of_memory+0x125/0x570 mem_cgroup_out_of_memory+0xb5/0xd0 try_charge+0x720/0x770 mem_cgroup_try_charge+0x86/0x180 mem_cgroup_try_charge_delay+0x1c/0x40 do_anonymous_page+0xb5/0x390 handle_mm_fault+0xc4/0x1f0 This is because thousands of processes are in the OOM cgroup, it takes a long time to traverse all of them. As a result, this lead to soft lockup in the OOM process. To fix this issue, add 'cond_resched' in the 'dump_task' function. Fixes: 9cbb78bb3143 ("mm, memcg: introduce own oom handler to iterate only = over its own threads") Signed-off-by: Chen Ridong --- mm/oom_kill.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 1c485beb0b93..14260381cccc 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -390,6 +390,7 @@ static int dump_task(struct task_struct *p, void *arg) if (!is_memcg_oom(oc) && !oom_cpuset_eligible(p, oc)) return 0; =20 + cond_resched(); task =3D find_lock_task_mm(p); if (!task) { /* --=20 2.34.1