From nobody Mon Apr 13 13:28:11 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3485C433FE for ; Sat, 12 Nov 2022 12:16:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234584AbiKLMPz (ORCPT ); Sat, 12 Nov 2022 07:15:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231570AbiKLMPw (ORCPT ); Sat, 12 Nov 2022 07:15:52 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A15111A38E for ; Sat, 12 Nov 2022 04:15:49 -0800 (PST) Received: from dggpemm500020.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4N8ZFJ1fxCzqSLh; Sat, 12 Nov 2022 20:12:04 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500020.china.huawei.com (7.185.36.49) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Sat, 12 Nov 2022 20:15:47 +0800 Received: from thunder-town.china.huawei.com (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Sat, 12 Nov 2022 20:15:47 +0800 From: Zhen Lei To: Andrew Morton , , CC: Zhen Lei , "Paul E . McKenney" , Zhang Qiang1 Subject: [PATCH] mm/vmalloc: allow mem_dump_obj() to be called in interrupt context Date: Sat, 12 Nov 2022 20:15:37 +0800 Message-ID: <20221112121537.1634-1-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.37.3.windows.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The function mem_dump_obj() can sometimes provide valuable debugging information, but it cannot be called in an interrupt context because spinlock vmap_area_lock has not been protected against IRQs. If the current task has held the lock before hard/soft interrupt handler calls mem_dump_obj(), simply abandoning the dump operation can avoid deadlock. That is, no deadlock occurs in extreme cases, and dump succeeds in most cases. Signed-off-by: Zhen Lei --- mm/vmalloc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index ccaa461998f3c37..cdd36c5a1aa16f8 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4034,6 +4034,9 @@ bool vmalloc_dump_obj(void *object) struct vm_struct *vm; void *objp =3D (void *)PAGE_ALIGN((unsigned long)object); =20 + if (unlikely(spin_is_locked(&vmap_area_lock))) + return false; + vm =3D find_vm_area(objp); if (!vm) return false; --=20 2.25.1