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 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
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-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon Mar 19 09:58:12 CET 2018
From: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com 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" kirill.shutemov@linux.intel.com
[ 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 fengguang.wu@intel.com Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Aneesh Kumar K.V aneesh.kumar@linux.vnet.ibm.com Cc: Kirill A. Shutemov kirill@shutemov.name Cc: LKP lkp@01.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170324114709.pcytvyb3d6ajux33@black.fi.intel.com Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/pagemap.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -153,7 +153,7 @@ 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 @@ -191,7 +191,7 @@ 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-4.4/mm-fix-false-positive-vm_bug_on-in-page_cache_-get-add-_speculative.patch