From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43B1FC433E0 for ; Wed, 10 Jun 2020 13:51:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28624207C3 for ; Wed, 10 Jun 2020 13:51:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729532AbgFJNvj (ORCPT ); Wed, 10 Jun 2020 09:51:39 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:5874 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726095AbgFJNvi (ORCPT ); Wed, 10 Jun 2020 09:51:38 -0400 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 4109B1ADA8F5DCDEDAA9; Wed, 10 Jun 2020 21:51:35 +0800 (CST) Received: from localhost (10.166.215.154) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.487.0; Wed, 10 Jun 2020 21:51:27 +0800 From: YueHaibing To: , , , , CC: YueHaibing Subject: [PATCH] ext4: mballoc: Disable preemption before getting per-CPU pointer Date: Wed, 10 Jun 2020 21:49:19 +0800 Message-ID: <20200610134919.73688-1-yuehaibing@huawei.com> X-Mailer: git-send-email 2.10.2.windows.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.166.215.154] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u16:3/2181 caller is ext4_mb_new_blocks+0x388/0xed0 CPU: 2 PID: 2181 Comm: kworker/u16:3 Not tainted 5.7.0+ #182 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Workqueue: writeback wb_workfn (flush-8:0) Call Trace: dump_stack+0xb9/0xfc debug_smp_processor_id+0xc8/0xd0 ext4_mb_new_blocks+0x388/0xed0 ext4_ext_map_blocks+0xa92/0xff0 ext4_map_blocks+0x34e/0x580 ext4_writepages+0xa28/0x11b0 do_writepages+0x46/0xe0 __writeback_single_inode+0x5f/0x6b0 writeback_sb_inodes+0x290/0x620 __writeback_inodes_wb+0x62/0xb0 wb_writeback+0x36c/0x520 wb_workfn+0x319/0x680 process_one_work+0x271/0x640 worker_thread+0x3a/0x3a0 kthread+0x14e/0x170 ret_from_fork+0x27/0x40 Disable preemption before accessing discard_pa_seq. Fixes: 07b5b8e1ac40 ("ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling") Signed-off-by: YueHaibing --- fs/ext4/mballoc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index a9083113a8c0..30b3bfb1e06a 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4708,7 +4708,8 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle, } ac->ac_op = EXT4_MB_HISTORY_PREALLOC; - seq = *this_cpu_ptr(&discard_pa_seq); + seq = *get_cpu_ptr(&discard_pa_seq); + put_cpu_ptr(&discard_pa_seq); if (!ext4_mb_use_preallocated(ac)) { ac->ac_op = EXT4_MB_HISTORY_ALLOC; ext4_mb_normalize_request(ac, ar); -- 2.20.1