From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34C2BC33C9B for ; Tue, 7 Jan 2020 20:58:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 026AB2087F for ; Tue, 7 Jan 2020 20:58:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578430704; bh=bXA2aXAoMwRwk9E7vq7jPFZdaJyFMqRgbUf+s41nX+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WZ3348mfXmm1vtaoRo00uyN4wF6RWeniwxIxDbFZtLVlIDjI00FYNB/V4CXw67Wgy JoSd9AAfEu/CXJuRpuDe4f6xd247dKfx8yxZdm410Gc//5404whfOvHqGysgKRASDB 3rA3SJBFiZWP3Tl064KaQK7vnkqlOdbraQExJRP8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727838AbgAGU6W (ORCPT ); Tue, 7 Jan 2020 15:58:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:57268 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727822AbgAGU6T (ORCPT ); Tue, 7 Jan 2020 15:58:19 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BB59221744; Tue, 7 Jan 2020 20:58:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578430698; bh=bXA2aXAoMwRwk9E7vq7jPFZdaJyFMqRgbUf+s41nX+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cXIXT2kc5lct4qw+7KvFhl0GVtvik+B5LZ4nqwEP3WAqHXPW6RXS8iK7S0H4JH/RD 3cnDRmC9gMD2mouBDN0UNsPmtGKHbYMVjmQ1f65TGvr18T7VWojVtgJPhJMsaZmDvw jzNm516xkFWN29zbcTWSLxDVQsLcq1YLUtazc6b4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Kirill A. Shutemov" , syzbot+03ee87124ee05af991bd@syzkaller.appspotmail.com, Johannes Weiner , "Matthew Wilcox (Oracle)" , Hillf Danton , Hugh Dickins , Josef Bacik , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 5.4 060/191] shmem: pin the file in shmem_fault() if mmap_sem is dropped Date: Tue, 7 Jan 2020 21:53:00 +0100 Message-Id: <20200107205336.207883389@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200107205332.984228665@linuxfoundation.org> References: <20200107205332.984228665@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kirill A. Shutemov [ Upstream commit 8897c1b1a1795cab23d5ac13e4e23bf0b5f4e0c6 ] syzbot found the following crash: BUG: KASAN: use-after-free in perf_trace_lock_acquire+0x401/0x530 include/trace/events/lock.h:13 Read of size 8 at addr ffff8880a5cf2c50 by task syz-executor.0/26173 CPU: 0 PID: 26173 Comm: syz-executor.0 Not tainted 5.3.0-rc6 #146 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: perf_trace_lock_acquire+0x401/0x530 include/trace/events/lock.h:13 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x2de/0x410 kernel/locking/lockdep.c:4411 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] shmem_fault+0x5ec/0x7b0 mm/shmem.c:2034 __do_fault+0x111/0x540 mm/memory.c:3083 do_shared_fault mm/memory.c:3535 [inline] do_fault mm/memory.c:3613 [inline] handle_pte_fault mm/memory.c:3840 [inline] __handle_mm_fault+0x2adf/0x3f20 mm/memory.c:3964 handle_mm_fault+0x1b5/0x6b0 mm/memory.c:4001 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline] __do_page_fault+0x536/0xdd0 arch/x86/mm/fault.c:1506 do_page_fault+0x38/0x590 arch/x86/mm/fault.c:1530 page_fault+0x39/0x40 arch/x86/entry/entry_64.S:1202 It happens if the VMA got unmapped under us while we dropped mmap_sem and inode got freed. Pinning the file if we drop mmap_sem fixes the issue. Link: http://lkml.kernel.org/r/20190927083908.rhifa4mmaxefc24r@box Signed-off-by: Kirill A. Shutemov Reported-by: syzbot+03ee87124ee05af991bd@syzkaller.appspotmail.com Acked-by: Johannes Weiner Reviewed-by: Matthew Wilcox (Oracle) Cc: Hillf Danton Cc: Hugh Dickins Cc: Josef Bacik Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/shmem.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 7a22e3e03d11..6074714fdbd4 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2022,16 +2022,14 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) shmem_falloc->waitq && vmf->pgoff >= shmem_falloc->start && vmf->pgoff < shmem_falloc->next) { + struct file *fpin; wait_queue_head_t *shmem_falloc_waitq; DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function); ret = VM_FAULT_NOPAGE; - if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) && - !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { - /* It's polite to up mmap_sem if we can */ - up_read(&vma->vm_mm->mmap_sem); + fpin = maybe_unlock_mmap_for_io(vmf, NULL); + if (fpin) ret = VM_FAULT_RETRY; - } shmem_falloc_waitq = shmem_falloc->waitq; prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait, @@ -2049,6 +2047,9 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) spin_lock(&inode->i_lock); finish_wait(shmem_falloc_waitq, &shmem_fault_wait); spin_unlock(&inode->i_lock); + + if (fpin) + fput(fpin); return ret; } spin_unlock(&inode->i_lock); -- 2.20.1