From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752460AbdAYS1j (ORCPT ); Wed, 25 Jan 2017 13:27:39 -0500 Received: from mga11.intel.com ([192.55.52.93]:5483 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752191AbdAYS1g (ORCPT ); Wed, 25 Jan 2017 13:27:36 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,285,1477983600"; d="scan'208";a="926591987" From: "Kirill A. Shutemov" To: Andrea Arcangeli , Hugh Dickins , Rik van Riel , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , Oleg Nesterov , Peter Zijlstra Subject: [PATCHv2 01/12] uprobes: split THPs before trying replace them Date: Wed, 25 Jan 2017 21:25:27 +0300 Message-Id: <20170125182538.86249-2-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170125182538.86249-1-kirill.shutemov@linux.intel.com> References: <20170125182538.86249-1-kirill.shutemov@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For THPs page_check_address() always fails. It leads to endless loop in uprobe_write_opcode(). Testcase with huge-tmpfs (not sure if it's possible to trigger this uprobe codepath for anon memory): mount -t debugfs none /sys/kernel/debug mount -t tmpfs -o huge=always none /mnt gcc -Wall -O2 -o /mnt/test -x c - < /sys/kernel/debug/tracing/uprobe_events echo 1 > /sys/kernel/debug/tracing/events/uprobes/enable /mnt/test Let's split THPs before trying to replace. Signed-off-by: Kirill A. Shutemov Acked-by: Rik van Riel Acked-by: Johannes Weiner Cc: Oleg Nesterov Cc: Peter Zijlstra --- kernel/events/uprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index d416f3baf392..1e65c79e52a6 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -300,8 +300,8 @@ int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr, retry: /* Read the page with vaddr into memory */ - ret = get_user_pages_remote(NULL, mm, vaddr, 1, FOLL_FORCE, &old_page, - &vma, NULL); + ret = get_user_pages_remote(NULL, mm, vaddr, 1, + FOLL_FORCE | FOLL_SPLIT, &old_page, &vma, NULL); if (ret <= 0) return ret; -- 2.11.0