From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id E28616B028A for ; Sun, 29 Jan 2017 12:39:37 -0500 (EST) Received: by mail-pg0-f69.google.com with SMTP id 3so172296135pgj.6 for ; Sun, 29 Jan 2017 09:39:37 -0800 (PST) Received: from mga06.intel.com (mga06.intel.com. [134.134.136.31]) by mx.google.com with ESMTPS id v17si1445361pgi.136.2017.01.29.09.39.36 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 29 Jan 2017 09:39:37 -0800 (PST) From: "Kirill A. Shutemov" Subject: [PATCHv3 01/12] uprobes: split THPs before trying replace them Date: Sun, 29 Jan 2017 20:38:47 +0300 Message-Id: <20170129173858.45174-2-kirill.shutemov@linux.intel.com> In-Reply-To: <20170129173858.45174-1-kirill.shutemov@linux.intel.com> References: <20170129173858.45174-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: 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 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org