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From: syzbot <>
Subject: KASAN: slab-out-of-bounds Read in handle_vmptrld
Date: Wed, 11 Sep 2019 13:38:08 -0700	[thread overview]
Message-ID: <> (raw)


syzbot found the following crash on:

HEAD commit:    1e3778cb Merge tag 'scsi-fixes' of git://
git tree:       upstream
console output:
kernel config:
dashboard link:
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:
C reproducer:

The bug was bisected to:

commit a87f854ddcf7ff7e044d72db0aa6da82f26d69a6
Author: Neil Armstrong <>
Date:   Wed Oct 11 15:39:40 2017 +0000

     ARM64: dts: meson-gx: remove unnecessary uart compatible

bisection log:
final crash:
console output:

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Fixes: a87f854ddcf7 ("ARM64: dts: meson-gx: remove unnecessary uart  

L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and for  
BUG: KASAN: slab-out-of-bounds in handle_vmptrld  
arch/x86/kvm/vmx/nested.c:4789 [inline]
BUG: KASAN: slab-out-of-bounds in handle_vmptrld+0x777/0x800  
Read of size 4 at addr ffff888091e10000 by task syz-executor758/10006

CPU: 1 PID: 10006 Comm: syz-executor758 Not tainted 5.3.0-rc7+ #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+0x172/0x1f0 lib/dump_stack.c:113
  print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351
  __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482
  kasan_report+0x12/0x17 mm/kasan/common.c:618
  __asan_report_load_n_noabort+0xf/0x20 mm/kasan/generic_report.c:142
  handle_vmptrld arch/x86/kvm/vmx/nested.c:4789 [inline]
  handle_vmptrld+0x777/0x800 arch/x86/kvm/vmx/nested.c:4749
  vmx_handle_exit+0x299/0x15e0 arch/x86/kvm/vmx/vmx.c:5886
  vcpu_enter_guest+0x1087/0x5e90 arch/x86/kvm/x86.c:8088
  vcpu_run arch/x86/kvm/x86.c:8152 [inline]
  kvm_arch_vcpu_ioctl_run+0x464/0x1750 arch/x86/kvm/x86.c:8360
  kvm_vcpu_ioctl+0x4dc/0xfd0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2765
  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+0xfd/0x6a0 arch/x86/entry/common.c:296
RIP: 0033:0x447269
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 3b d0 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd58df6ad8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffd58df6ae0 RCX: 0000000000447269
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000020003800 R09: 0000000000400e80
R10: 00007ffd58df4f20 R11: 0000000000000246 R12: 0000000000404730
R13: 00000000004047c0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 10006:
  save_stack+0x23/0x90 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  __kasan_kmalloc mm/kasan/common.c:493 [inline]
  __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:466
  kasan_kmalloc+0x9/0x10 mm/kasan/common.c:507
  __do_kmalloc mm/slab.c:3655 [inline]
  __kmalloc+0x163/0x770 mm/slab.c:3664
  kmalloc include/linux/slab.h:557 [inline]
  hcd_buffer_alloc+0x1c6/0x260 drivers/usb/core/buffer.c:132
  usb_alloc_coherent+0x62/0x90 drivers/usb/core/usb.c:910
  usbdev_mmap+0x1ce/0x790 drivers/usb/core/devio.c:224
  call_mmap include/linux/fs.h:1875 [inline]
  mmap_region+0xc35/0x1760 mm/mmap.c:1788
  do_mmap+0x82e/0x1090 mm/mmap.c:1561
  do_mmap_pgoff include/linux/mm.h:2374 [inline]
  vm_mmap_pgoff+0x1c5/0x230 mm/util.c:391
  ksys_mmap_pgoff+0x4aa/0x630 mm/mmap.c:1611
  __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
  __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline]
  __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91
  do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296

Freed by task 9516:
  save_stack+0x23/0x90 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  __kasan_slab_free+0x102/0x150 mm/kasan/common.c:455
  kasan_slab_free+0xe/0x10 mm/kasan/common.c:463
  __cache_free mm/slab.c:3425 [inline]
  kfree+0x10a/0x2c0 mm/slab.c:3756
  tomoyo_init_log+0x15ba/0x2070 security/tomoyo/audit.c:293
  tomoyo_supervisor+0x33f/0xef0 security/tomoyo/common.c:2095
  tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
  tomoyo_env_perm+0x18e/0x210 security/tomoyo/environ.c:63
  tomoyo_environ security/tomoyo/domain.c:670 [inline]
  tomoyo_find_next_domain+0x1354/0x1f6c security/tomoyo/domain.c:876
  tomoyo_bprm_check_security security/tomoyo/tomoyo.c:107 [inline]
  tomoyo_bprm_check_security+0x124/0x1b0 security/tomoyo/tomoyo.c:97
  security_bprm_check+0x63/0xb0 security/security.c:750
  search_binary_handler+0x71/0x570 fs/exec.c:1645
  exec_binprm fs/exec.c:1701 [inline]
  __do_execve_file.isra.0+0x1333/0x2340 fs/exec.c:1821
  do_execveat_common fs/exec.c:1868 [inline]
  do_execve fs/exec.c:1885 [inline]
  __do_sys_execve fs/exec.c:1961 [inline]
  __se_sys_execve fs/exec.c:1956 [inline]
  __x64_sys_execve+0x8f/0xc0 fs/exec.c:1956
  do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296

The buggy address belongs to the object at ffff888091e109c0
  which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2496 bytes to the left of
  8192-byte region [ffff888091e109c0, ffff888091e129c0)
The buggy address belongs to the page:
page:ffffea0002478400 refcount:2 mapcount:0 mapping:ffff8880aa4021c0  
index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea000242e608 ffffea0002436708 ffff8880aa4021c0
raw: 0000000000000000 ffff888091e109c0 0000000200000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff888091e0ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffff888091e0ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff888091e10000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffff888091e10080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffff888091e10100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

This bug is generated by a bot. It may contain errors.
See for more information about syzbot.
syzbot engineers can be reached at

syzbot will keep track of this bug report. See: for how to communicate with syzbot.
For information about bisection process see:
syzbot can test patches for this bug, for details see:

linux-amlogic mailing list

             reply	other threads:[~2019-09-11 20:38 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-11 20:38 syzbot [this message]
2019-09-12 12:25 ` KASAN: slab-out-of-bounds Read in handle_vmptrld Will Deacon
2019-09-12 13:54 ` Vitaly Kuznetsov
2019-09-12 16:49   ` Paolo Bonzini
2019-09-13  4:46     ` Greg Kroah-Hartman
2019-09-13  7:34       ` Paolo Bonzini
2019-09-13 13:02         ` Greg Kroah-Hartman
2019-09-13 15:01           ` Paolo Bonzini
2019-09-13 15:32             ` Robin Murphy
2019-09-13 21:39               ` Paolo Bonzini
2019-09-13 15:36             ` Alan Stern
2019-09-13 16:14               ` Paolo Bonzini

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