From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45702 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932632AbeCSJPE (ORCPT ); Mon, 19 Mar 2018 05:15:04 -0400 Subject: Patch "mm: Fix false-positive VM_BUG_ON() in page_cache_{get,add}_speculative()" has been added to the 3.18-stable tree To: kirill.shutemov@linux.intel.com, akpm@linux-foundation.org, alexander.levin@microsoft.com, aneesh.kumar@linux.vnet.ibm.com, fengguang.wu@intel.com, gregkh@linuxfoundation.org, kirill@shutemov.name, lkp@01.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org Cc: , From: Date: Mon, 19 Mar 2018 10:13:09 +0100 Message-ID: <152145078913724@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: Fix false-positive VM_BUG_ON() in page_cache_{get,add}_speculative() 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-fix-false-positive-vm_bug_on-in-page_cache_-get-add-_speculative.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 foo@baz Mon Mar 19 10:11:52 CET 2018 From: "Kirill A. Shutemov" Date: Fri, 24 Mar 2017 14:13:05 +0300 Subject: mm: Fix false-positive VM_BUG_ON() in page_cache_{get,add}_speculative() From: "Kirill A. Shutemov" [ Upstream commit 591a3d7c09fa08baff48ad86c2347dbd28a52753 ] 0day testing by Fengguang Wu triggered this crash while running Trinity: kernel BUG at include/linux/pagemap.h:151! ... CPU: 0 PID: 458 Comm: trinity-c0 Not tainted 4.11.0-rc2-00251-g2947ba0 #1 ... Call Trace: __get_user_pages_fast() get_user_pages_fast() get_futex_key() futex_requeue() do_futex() SyS_futex() do_syscall_64() entry_SYSCALL64_slow_path() It' VM_BUG_ON() due to false-negative in_atomic(). We call page_cache_get_speculative() with disabled local interrupts. It should be atomic enough. So let's check for disabled interrupts in the VM_BUG_ON() condition too, to resolve this. ( This got triggered by the conversion of the x86 GUP code to the generic GUP code. ) Reported-by: Fengguang Wu Signed-off-by: Kirill A. Shutemov Cc: Andrew Morton Cc: Aneesh Kumar K.V Cc: Kirill A. Shutemov Cc: LKP Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170324114709.pcytvyb3d6ajux33@black.fi.intel.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- include/linux/pagemap.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -146,7 +146,7 @@ static inline int page_cache_get_specula #ifdef CONFIG_TINY_RCU # ifdef CONFIG_PREEMPT_COUNT - VM_BUG_ON(!in_atomic()); + VM_BUG_ON(!in_atomic() && !irqs_disabled()); # endif /* * Preempt must be disabled here - we rely on rcu_read_lock doing @@ -184,7 +184,7 @@ static inline int page_cache_add_specula #if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU) # ifdef CONFIG_PREEMPT_COUNT - VM_BUG_ON(!in_atomic()); + VM_BUG_ON(!in_atomic() && !irqs_disabled()); # endif VM_BUG_ON_PAGE(page_count(page) == 0, page); atomic_add(count, &page->_count); Patches currently in stable-queue which might be from kirill.shutemov@linux.intel.com are queue-3.18/mm-fix-false-positive-vm_bug_on-in-page_cache_-get-add-_speculative.patch