From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:59240 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751869AbdHGVDM (ORCPT ); Mon, 7 Aug 2017 17:03:12 -0400 Subject: Patch "mm/page_alloc: Remove kernel address exposure in free_reserved_area()" has been added to the 3.18-stable tree To: jpoimboe@redhat.com, bp@alien8.de, brgerst@gmail.com, dvlasenk@redhat.com, gregkh@linuxfoundation.org, hpa@zytor.com, keescook@google.com, luto@kernel.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org Cc: , From: Date: Mon, 07 Aug 2017 14:03:11 -0700 Message-ID: <150213979125082@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled mm/page_alloc: Remove kernel address exposure in free_reserved_area() to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-page_alloc-remove-kernel-address-exposure-in-free_reserved_area.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From adb1fe9ae2ee6ef6bc10f3d5a588020e7664dfa7 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Tue, 25 Oct 2016 09:51:14 -0500 Subject: mm/page_alloc: Remove kernel address exposure in free_reserved_area() From: Josh Poimboeuf commit adb1fe9ae2ee6ef6bc10f3d5a588020e7664dfa7 upstream. Linus suggested we try to remove some of the low-hanging fruit related to kernel address exposure in dmesg. The only leaks I see on my local system are: Freeing SMP alternatives memory: 32K (ffffffff9e309000 - ffffffff9e311000) Freeing initrd memory: 10588K (ffffa0b736b42000 - ffffa0b737599000) Freeing unused kernel memory: 3592K (ffffffff9df87000 - ffffffff9e309000) Freeing unused kernel memory: 1352K (ffffa0b7288ae000 - ffffa0b728a00000) Freeing unused kernel memory: 632K (ffffa0b728d62000 - ffffa0b728e00000) Linus says: "I suspect we should just remove [the addresses in the 'Freeing' messages]. I'm sure they are useful in theory, but I suspect they were more useful back when the whole "free init memory" was originally done. These days, if we have a use-after-free, I suspect the init-mem situation is the easiest situation by far. Compared to all the dynamic allocations which are much more likely to show it anyway. So having debug output for that case is likely not all that productive." With this patch the freeing messages now look like this: Freeing SMP alternatives memory: 32K Freeing initrd memory: 10588K Freeing unused kernel memory: 3592K Freeing unused kernel memory: 1352K Freeing unused kernel memory: 632K Suggested-by: Linus Torvalds Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/6836ff90c45b71d38e5d4405aec56fa9e5d1d4b2.1477405374.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar Cc: Kees Cook Signed-off-by: Greg Kroah-Hartman --- mm/page_alloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5467,8 +5467,8 @@ unsigned long free_reserved_area(void *s } if (pages && s) - pr_info("Freeing %s memory: %ldK (%p - %p)\n", - s, pages << (PAGE_SHIFT - 10), start, end); + pr_info("Freeing %s memory: %ldK\n", + s, pages << (PAGE_SHIFT - 10)); return pages; } Patches currently in stable-queue which might be from jpoimboe@redhat.com are queue-3.18/mm-page_alloc-remove-kernel-address-exposure-in-free_reserved_area.patch