From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751569AbeDYTTF (ORCPT ); Wed, 25 Apr 2018 15:19:05 -0400 Received: from mail-io0-f199.google.com ([209.85.223.199]:53034 "EHLO mail-io0-f199.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751093AbeDYTTD (ORCPT ); Wed, 25 Apr 2018 15:19:03 -0400 X-Google-Smtp-Source: AIpwx49e/VRjrpgbcmxf3QDq1cPcFSdHAhdwI+DvdB1flTXIy5hjnW3ncOanDrQMzT16M8yWuNW7wpcOy0Mnx8nAHhtRM93v3red MIME-Version: 1.0 Date: Wed, 25 Apr 2018 12:19:02 -0700 In-Reply-To: <000000000000a5b2b1056a86e98c@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000cf4578056ab12452@google.com> Subject: Re: KMSAN: uninit-value in _copy_to_iter (2) From: syzbot To: avagin@openvz.org, davem@davemloft.net, dingtianhong@huawei.com, edumazet@google.com, elena.reshetova@intel.com, jasowang@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, matthew@mjdsystems.ca, mingo@kernel.org, mst@redhat.com, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, virtualization@lists.linux-foundation.org, willemb@google.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot has found reproducer for the following crash on https://github.com/google/kmsan.git/master commit d2d741e5d1898dfde1a75ea3d29a9a3e2edf0617 (Sun Apr 22 15:05:22 2018 +0000) kmsan: add initialization for shmem pages syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=87cfa083e727a224754b So far this crash happened 3 times on https://github.com/google/kmsan.git/master. C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5122017598636032 syzkaller reproducer: https://syzkaller.appspot.com/x/repro.syz?id=6680049734385664 Raw console output: https://syzkaller.appspot.com/x/log.txt?id=5920461749747712 Kernel config: https://syzkaller.appspot.com/x/.config?id=328654897048964367 compiler: clang version 7.0.0 (trunk 329391) IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+87cfa083e727a224754b@syzkaller.appspotmail.com It will help syzbot understand when the bug is fixed. ================================================================== BUG: KMSAN: uninit-value in copyout lib/iov_iter.c:140 [inline] BUG: KMSAN: uninit-value in _copy_to_iter+0x46d/0x28f0 lib/iov_iter.c:571 CPU: 1 PID: 4516 Comm: syz-executor879 Not tainted 4.16.0+ #87 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 kmsan_internal_check_memory+0x135/0x1e0 mm/kmsan/kmsan.c:1157 kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199 copyout lib/iov_iter.c:140 [inline] _copy_to_iter+0x46d/0x28f0 lib/iov_iter.c:571 copy_to_iter include/linux/uio.h:106 [inline] vhost_chr_read_iter+0x7ac/0xc50 drivers/vhost/vhost.c:1104 vhost_net_chr_read_iter+0xf6/0x130 drivers/vhost/net.c:1365 call_read_iter include/linux/fs.h:1776 [inline] aio_read+0x5c1/0x6f0 fs/aio.c:1517 io_submit_one fs/aio.c:1633 [inline] do_io_submit+0x1bb4/0x2f60 fs/aio.c:1698 SYSC_io_submit+0x98/0xb0 fs/aio.c:1723 SyS_io_submit+0x56/0x80 fs/aio.c:1720 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x4457b9 RSP: 002b:00007ff9343e4da8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 00000000006dac44 RCX: 00000000004457b9 RDX: 00000000200001c0 RSI: 0000000000000001 RDI: 00007ff93439a000 RBP: 00000000006dac40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 901aeeff3a98f9ab R13: 98c94b26f489688e R14: ae1b2dfa3c87200a R15: 0000000000000001 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314 __kmalloc+0x23c/0x350 mm/slub.c:3791 kmalloc include/linux/slab.h:517 [inline] vhost_new_msg drivers/vhost/vhost.c:2340 [inline] vhost_iotlb_miss drivers/vhost/vhost.c:1124 [inline] translate_desc+0xbef/0x1120 drivers/vhost/vhost.c:1829 __vhost_get_user_slow drivers/vhost/vhost.c:812 [inline] __vhost_get_user drivers/vhost/vhost.c:846 [inline] vhost_update_used_flags+0x469/0x8d0 drivers/vhost/vhost.c:1715 vhost_vq_init_access+0x173/0xa20 drivers/vhost/vhost.c:1763 vhost_net_set_backend drivers/vhost/net.c:1166 [inline] vhost_net_ioctl+0x22b0/0x3480 drivers/vhost/net.c:1322 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0xaf0/0x2440 fs/ioctl.c:686 SYSC_ioctl+0x1d2/0x260 fs/ioctl.c:701 SyS_ioctl+0x54/0x80 fs/ioctl.c:692 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Bytes 4-7 of 72 are uninitialized ==================================================================