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=-5.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS 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 1FBE2C43215 for ; Mon, 2 Dec 2019 17:05:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EACFE20848 for ; Mon, 2 Dec 2019 17:05:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727805AbfLBRFR (ORCPT ); Mon, 2 Dec 2019 12:05:17 -0500 Received: from mail-il1-f197.google.com ([209.85.166.197]:39408 "EHLO mail-il1-f197.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id 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X-Received: by 2002:a6b:d912:: with SMTP id r18mr42792632ioc.306.1575306310599; Mon, 02 Dec 2019 09:05:10 -0800 (PST) Date: Mon, 02 Dec 2019 09:05:10 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000000e4f720598bb95f8@google.com> Subject: KASAN: use-after-free Read in slcan_open From: syzbot To: davem@davemloft.net, linux-can@vger.kernel.org, linux-kernel@vger.kernel.org, mkl@pengutronix.de, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, wg@grandegger.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 32ef9553 Merge tag 'fsnotify_for_v5.5-rc1' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12a48e9ce00000 kernel config: https://syzkaller.appspot.com/x/.config?x=ff560c3de405258c dashboard link: https://syzkaller.appspot.com/bug?extid=b5ec6fd05ab552a78532 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12943882e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10562f86e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+b5ec6fd05ab552a78532@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in slc_sync drivers/net/can/slcan.c:504 [inline] BUG: KASAN: use-after-free in slcan_open+0x8a1/0x9e0 drivers/net/can/slcan.c:579 Read of size 8 at addr ffff88809a6e0b88 by task syz-executor961/9030 CPU: 1 PID: 9030 Comm: syz-executor961 Not tainted 5.4.0-syzkaller #0 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+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:634 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 slc_sync drivers/net/can/slcan.c:504 [inline] slcan_open+0x8a1/0x9e0 drivers/net/can/slcan.c:579 tty_ldisc_open.isra.0+0xa3/0x110 drivers/tty/tty_ldisc.c:469 tty_set_ldisc+0x30e/0x6b0 drivers/tty/tty_ldisc.c:596 tiocsetd drivers/tty/tty_io.c:2334 [inline] tty_ioctl+0xe8d/0x14f0 drivers/tty/tty_io.c:2594 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4429e9 Code: e8 dc 02 03 00 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 1b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc7db87168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004429e9 RDX: 00000000200000c0 RSI: 0000000000005423 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000002 R09: 0000000000003031 R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff R13: 0000000000000004 R14: 00007ffc7db871dc R15: 0000000000000000 Allocated by task 9029: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:510 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524 __do_kmalloc_node mm/slab.c:3615 [inline] __kmalloc_node+0x4e/0x70 mm/slab.c:3622 kmalloc_node include/linux/slab.h:599 [inline] kvmalloc_node+0xbd/0x100 mm/util.c:564 kvmalloc include/linux/mm.h:670 [inline] kvzalloc include/linux/mm.h:678 [inline] alloc_netdev_mqs+0x98/0xde0 net/core/dev.c:9730 slc_alloc drivers/net/can/slcan.c:533 [inline] slcan_open+0x32d/0x9e0 drivers/net/can/slcan.c:590 tty_ldisc_open.isra.0+0xa3/0x110 drivers/tty/tty_ldisc.c:469 tty_set_ldisc+0x30e/0x6b0 drivers/tty/tty_ldisc.c:596 tiocsetd drivers/tty/tty_io.c:2334 [inline] tty_ioctl+0xe8d/0x14f0 drivers/tty/tty_io.c:2594 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9029: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] kasan_set_free_info mm/kasan/common.c:332 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:471 kasan_slab_free+0xe/0x10 mm/kasan/common.c:480 __cache_free mm/slab.c:3425 [inline] kfree+0x10a/0x2c0 mm/slab.c:3756 kvfree+0x61/0x70 mm/util.c:593 netdev_freemem net/core/dev.c:9684 [inline] free_netdev+0x3c0/0x470 net/core/dev.c:9839 slcan_open+0x848/0x9e0 drivers/net/can/slcan.c:620 tty_ldisc_open.isra.0+0xa3/0x110 drivers/tty/tty_ldisc.c:469 tty_set_ldisc+0x30e/0x6b0 drivers/tty/tty_ldisc.c:596 tiocsetd drivers/tty/tty_io.c:2334 [inline] tty_ioctl+0xe8d/0x14f0 drivers/tty/tty_io.c:2594 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88809a6e0000 which belongs to the cache kmalloc-32k of size 32768 The buggy address is located 2952 bytes inside of 32768-byte region [ffff88809a6e0000, ffff88809a6e8000) The buggy address belongs to the page: page:ffffea000269b800 refcount:1 mapcount:0 mapping:ffff8880aa402540 index:0x0 compound_mapcount: 0 raw: 00fffe0000010200 ffffea000244d008 ffff8880aa401d48 ffff8880aa402540 raw: 0000000000000000 ffff88809a6e0000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809a6e0a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809a6e0b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88809a6e0b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809a6e0c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809a6e0c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches