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=-0.7 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 9172AC46460 for ; Sun, 12 Aug 2018 20:50:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 35B7221A0B for ; Sun, 12 Aug 2018 20:50:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 35B7221A0B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727839AbeHLX3Q (ORCPT ); Sun, 12 Aug 2018 19:29:16 -0400 Received: from mail-io0-f200.google.com ([209.85.223.200]:46527 "EHLO mail-io0-f200.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727691AbeHLX3Q (ORCPT ); Sun, 12 Aug 2018 19:29:16 -0400 Received: by mail-io0-f200.google.com with SMTP id c5-v6so12284145ioi.13 for ; Sun, 12 Aug 2018 13:50:02 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id:subject :from:to; bh=b/YL1d/3twwn3mQrHGKvCkMdUeXGcgC316y8yBo/A8Q=; b=KtqE1p8whhi6h0pve1VPoMLtZ9nIbTsM57PN8WvWZ130C8iRVORgq9JqkWUVLrVmcl z8zJspiBXy59WtueeIYhcrkNLsLAVK57bF8ePVFtM7CrqdzQzRg427/RnV49Bw+BMsIG 9uPBthbJb5gscahHuikbpgqEqkqGyrrKmnN1s5GN7zThYmahyfzTwMGkU62fUFYOsd+J FzbIJx2twmfiEeyzYUzlOvX5/rojE0KDe5ag+xDAbxn+p9ixb3OhuqQskMaXPbJThdET 7rb6/vCavFgVzChuD9rfbtFnGJV0ARGIbkjtlyICGKQi6kDuSS2BUlwL56wXFGQvssty eNdw== X-Gm-Message-State: AOUpUlG9R2UbO+Gfge+SXj81kcNISH+LXbX8eKrKtcyppANr0ZcIRA15 B2w5VfT6huSAVrUGAKEqmjLQjYOrlJ1xPgSUD6ZJdPgq+N/f X-Google-Smtp-Source: AA+uWPwwenswGTvVStBJwGfUzCR3mY/vNX02juv5Wpg/Gfxt/QB744Hqp6mW16VChSdjx8EmeBhX49vJe4i6bAfyTS4xe3x+FsMG MIME-Version: 1.0 X-Received: by 2002:a6b:db05:: with SMTP id t5-v6mr6882348ioc.15.1534107002232; Sun, 12 Aug 2018 13:50:02 -0700 (PDT) Date: Sun, 12 Aug 2018 13:50:02 -0700 In-Reply-To: <000000000000e106310573146798@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000ea6b380573431e98@google.com> Subject: Re: KASAN: use-after-free Read in finish_task_switch From: syzbot To: akpm@linux-foundation.org, dan.j.williams@intel.com, dvhart@infradead.org, jglisse@redhat.com, jrdr.linux@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, minchan@kernel.org, mingo@redhat.com, peterz@infradead.org, riel@surriel.com, sfr@canb.auug.org.au, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, ying.huang@intel.com, zwisler@kernel.org Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 4110b42356f3 Add linux-next specific files for 20180810 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=107162c4400000 kernel config: https://syzkaller.appspot.com/x/.config?x=1d80606e3795a4f5 dashboard link: https://syzkaller.appspot.com/bug?extid=e62f8ba2b2af8dbd6729 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=16d33cc4400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=142c7202400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+e62f8ba2b2af8dbd6729@syzkaller.appspotmail.com random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) ================================================================== BUG: KASAN: use-after-free in __fire_sched_in_preempt_notifiers kernel/sched/core.c:2481 [inline] BUG: KASAN: use-after-free in fire_sched_in_preempt_notifiers kernel/sched/core.c:2487 [inline] BUG: KASAN: use-after-free in finish_task_switch+0x544/0x870 kernel/sched/core.c:2679 Read of size 8 at addr ffff8801c79482d8 by task syz-executor216/4445 CPU: 0 PID: 4445 Comm: syz-executor216 Not tainted 4.18.0-rc8-next-20180810+ #36 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 __fire_sched_in_preempt_notifiers kernel/sched/core.c:2481 [inline] fire_sched_in_preempt_notifiers kernel/sched/core.c:2487 [inline] finish_task_switch+0x544/0x870 kernel/sched/core.c:2679 context_switch kernel/sched/core.c:2826 [inline] __schedule+0x884/0x1ec0 kernel/sched/core.c:3471 schedule+0xfb/0x450 kernel/sched/core.c:3515 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x3f9/0x840 kernel/futex.c:2530 futex_wait+0x45b/0xa20 kernel/futex.c:2645 do_futex+0x336/0x27d0 kernel/futex.c:3527 __do_sys_futex kernel/futex.c:3587 [inline] __se_sys_futex kernel/futex.c:3555 [inline] __x64_sys_futex+0x472/0x6a0 kernel/futex.c:3555 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4468a9 Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f34d3e78da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00000000006dbc88 RCX: 00000000004468a9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000006dbc88 RBP: 00000000006dbc80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc8c R13: 0030656c69662f2e R14: 6c75662f7665642f R15: 00000000006dbd6c Allocated by task 4439: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554 kmem_cache_zalloc include/linux/slab.h:697 [inline] vmx_create_vcpu+0xcf/0x28b0 arch/x86/kvm/vmx.c:10682 kvm_arch_vcpu_create+0xe5/0x220 arch/x86/kvm/x86.c:8401 kvm_vm_ioctl_create_vcpu arch/x86/kvm/../../../virt/kvm/kvm_main.c:2476 [inline] kvm_vm_ioctl+0x488/0x1d80 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2977 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 __do_sys_ioctl fs/ioctl.c:709 [inline] __se_sys_ioctl fs/ioctl.c:707 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 4423: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x86/0x2d0 mm/slab.c:3756 vmx_free_vcpu+0x26b/0x300 arch/x86/kvm/vmx.c:10676 kvm_arch_vcpu_free arch/x86/kvm/x86.c:8387 [inline] kvm_free_vcpus arch/x86/kvm/x86.c:8836 [inline] kvm_arch_destroy_vm+0x365/0x7c0 arch/x86/kvm/x86.c:8933 kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:752 [inline] kvm_put_kvm+0x73f/0x1060 arch/x86/kvm/../../../virt/kvm/kvm_main.c:773 kvm_vcpu_release+0x7b/0xa0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2407 __fput+0x376/0x8a0 fs/file_table.c:279 ____fput+0x15/0x20 fs/file_table.c:312 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801c79482c0 which belongs to the cache kvm_vcpu of size 23808 The buggy address is located 24 bytes inside of 23808-byte region [ffff8801c79482c0, ffff8801c794dfc0) The buggy address belongs to the page: page:ffffea00071e5200 count:1 mapcount:0 mapping:ffff8801d4c35a80 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffffea000721fe08 ffffea0007364208 ffff8801d4c35a80 raw: 0000000000000000 ffff8801c79482c0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c7948180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801c7948200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801c7948280: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8801c7948300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c7948380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================