From patchwork Sat Mar 12 00:04:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12778670 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 AD4D0C433F5 for ; Sat, 12 Mar 2022 00:05:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229457AbiCLAGG (ORCPT ); Fri, 11 Mar 2022 19:06:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51166 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229580AbiCLAGF (ORCPT ); Fri, 11 Mar 2022 19:06:05 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 732AB20F60; Fri, 11 Mar 2022 16:05:00 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 06F05614DB; Sat, 12 Mar 2022 00:05:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBBA8C340E9; Sat, 12 Mar 2022 00:04:58 +0000 (UTC) Date: Fri, 11 Mar 2022 19:04:57 -0500 From: Steven Rostedt To: LKML Cc: Beau Belgrave , Anders Roxell , Masami Hiramatsu , Linux Trace Devel Subject: [PATCH] tracing/user_events: Use alloc_pages instead of kzalloc() for register pages Message-ID: <20220311190457.0345eeb2@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org From: "Steven Rostedt (Google)" kzalloc virtual addresses do not work with SetPageReserved, use the actual page virtual addresses instead via alloc_pages. The issue is reported when booting with user_events and DEBUG_VM_PGFLAGS=y. Also make the number of events based on the ORDER. Link: https://lore.kernel.org/all/CADYN=9+xY5Vku3Ws5E9S60SM5dCFfeGeRBkmDFbcxX0ZMoFing@mail.gmail.com/ Link: https://lore.kernel.org/all/20220311223028.1865-1-beaub@linux.microsoft.com/ Cc: Beau Belgrave Reported-by: Anders Roxell Signed-off-by: Steven Rostedt (Google) Acked-by: Masami Hiramatsu --- kernel/trace/trace_events_user.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 4febc1d6ae72..e10ad057e797 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -30,9 +30,10 @@ /* * Limits how many trace_event calls user processes can create: - * Must be multiple of PAGE_SIZE. + * Must be a power of two of PAGE_SIZE. */ -#define MAX_PAGES 1 +#define MAX_PAGE_ORDER 0 +#define MAX_PAGES (1 << MAX_PAGE_ORDER) #define MAX_EVENTS (MAX_PAGES * PAGE_SIZE) /* Limit how long of an event name plus args within the subsystem. */ @@ -1622,16 +1623,17 @@ static void set_page_reservations(bool set) static int __init trace_events_user_init(void) { + struct page *pages; int ret; /* Zero all bits beside 0 (which is reserved for failures) */ bitmap_zero(page_bitmap, MAX_EVENTS); set_bit(0, page_bitmap); - register_page_data = kzalloc(MAX_EVENTS, GFP_KERNEL); - - if (!register_page_data) + pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, MAX_PAGE_ORDER); + if (!pages) return -ENOMEM; + register_page_data = page_address(pages); set_page_reservations(true); @@ -1640,7 +1642,7 @@ static int __init trace_events_user_init(void) if (ret) { pr_warn("user_events could not register with tracefs\n"); set_page_reservations(false); - kfree(register_page_data); + __free_pages(pages, MAX_PAGE_ORDER); return ret; }