KASAN: use-after-free Read in __loaded_vmcs_clear

From: syzbot
Date: Tue Aug 21 2018 - 11:24:11 EST

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Hello,

syzbot found the following crash on:

HEAD commit: cc26ebbebde8 ia64: Fix kernel BUG at lib/ioremap.c:72!
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=144c89de400000
kernel config: https://syzkaller.appspot.com/x/.config?x=79e695838ce7a210
dashboard link: https://syzkaller.appspot.com/bug?extid=c26aa916bc6caa4853dd
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c26aa916bc6caa4853dd@xxxxxxxxxxxxxxxxxxxxxxxxx

RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000006
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004ce9b8 R14: 00000000004c50d7 R15: 0000000000000000
==================================================================
BUG: KASAN: use-after-free in __list_del_entry_valid+0xf1/0xf3 lib/list_debug.c:51
Read of size 8 at addr ffff880191f766e0 by task syz-executor3/1383

CPU: 1 PID: 1383 Comm: syz-executor3 Not tainted 4.18.0+ #199
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__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
__list_del_entry_valid+0xf1/0xf3 lib/list_debug.c:51
__list_del_entry include/linux/list.h:117 [inline]
list_del include/linux/list.h:125 [inline]
__loaded_vmcs_clear+0x14f/0x630 arch/x86/kvm/vmx.c:2187
flush_smp_call_function_queue+0x1a8/0x5e0 kernel/smp.c:243
generic_smp_call_function_single_interrupt+0x13/0x2b kernel/smp.c:192
smp_call_function_single_interrupt+0x11a/0x670 arch/x86/kernel/smp.c:296
call_function_single_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:886
</IRQ>
RIP: 0010:arch_local_irq_restore+0x4a/0x52 arch/x86/include/asm/paravirt.h:783
Code: 48 c1 ea 03 80 3c 02 00 74 05 e8 b9 ef 0b fb 48 83 3d a9 53 41 01 00 75 07 e8 9a f8 cc fa 0f 0b e8 93 f8 cc fa 48 89 df 57 9d <0f> 1f 44 00 00 5b 5d c3 4c 89 45 d0 e8 6d ef 0b fb 4c 8b 45 d0 e9
RSP: 0018:ffff8801cc1fef90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff04
RAX: 0000000000040000 RBX: 0000000000000246 RCX: ffffc9000341f000
RDX: 0000000000040000 RSI: ffffffff86b0690d RDI: 0000000000000246
RBP: ffff8801cc1fef98 R08: ffff88018a440df8 R09: 0000000000000006
R10: ffff88018a4405c0 R11: 0000000000000000 R12: 0000000000000200
R13: 1ffff1003983fdfc R14: ffffffff87f1bca0 R15: 00000000ffffffff
dump_stack+0x273/0x2b4 lib/dump_stack.c:118
vmwrite_error+0x4c/0x60 arch/x86/kvm/vmx.c:2352
__vmcs_writel arch/x86/kvm/vmx.c:2362 [inline]
vmcs_writel arch/x86/kvm/vmx.c:2402 [inline]
vmx_vcpu_load+0xcad/0xfe0 arch/x86/kvm/vmx.c:3085
kvm_arch_vcpu_load+0x22b/0x940 arch/x86/kvm/x86.c:3106
kvm_sched_in+0x82/0xa0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3970
__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+0x50d/0x870 kernel/sched/core.c:2679
context_switch kernel/sched/core.c:2826 [inline]
__schedule+0x884/0x1ec0 kernel/sched/core.c:3471
preempt_schedule_common+0x22/0x60 kernel/sched/core.c:3595
_cond_resched+0x1d/0x30 kernel/sched/core.c:4961
slab_pre_alloc_hook mm/slab.h:421 [inline]
slab_alloc mm/slab.c:3378 [inline]
kmem_cache_alloc+0x2a5/0x760 mm/slab.c:3552
alloc_inode+0xb2/0x190 fs/inode.c:212
new_inode_pseudo+0x71/0x1a0 fs/inode.c:903
new_inode+0x1c/0x40 fs/inode.c:932
debugfs_get_inode+0x19/0x120 fs/debugfs/inode.c:37
__debugfs_create_file+0xb5/0x400 fs/debugfs/inode.c:352
debugfs_create_file+0x57/0x70 fs/debugfs/inode.c:399
kvm_create_vm_debugfs arch/x86/kvm/../../../virt/kvm/kvm_main.c:615 [inline]
kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3209 [inline]
kvm_dev_ioctl+0xbf5/0x1b10 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3236
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
__do_sys_ioctl fs/ioctl.c:708 [inline]
__se_sys_ioctl fs/ioctl.c:706 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457089
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fdd4b708c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fdd4b7096d4 RCX: 0000000000457089
RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000006
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004ce9b8 R14: 00000000004c50d7 R15: 0000000000000000

Allocated by task 1383:
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/0x27c0 arch/x86/kvm/vmx.c:10926
kvm_arch_vcpu_create+0xe5/0x220 arch/x86/kvm/x86.c:8433
kvm_vm_ioctl_create_vcpu arch/x86/kvm/../../../virt/kvm/kvm_main.c:2471 [inline]
kvm_vm_ioctl+0x488/0x1d80 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2972
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
__do_sys_ioctl fs/ioctl.c:708 [inline]
__se_sys_ioctl fs/ioctl.c:706 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 1374:
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:10920
kvm_arch_vcpu_free arch/x86/kvm/x86.c:8419 [inline]
kvm_free_vcpus arch/x86/kvm/x86.c:8869 [inline]
kvm_arch_destroy_vm+0x365/0x7c0 arch/x86/kvm/x86.c:8966
kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:747 [inline]
kvm_put_kvm+0x73f/0x1060 arch/x86/kvm/../../../virt/kvm/kvm_main.c:768
kvm_vcpu_release+0x7b/0xa0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2402
__fput+0x39b/0x860 fs/file_table.c:251
____fput+0x15/0x20 fs/file_table.c:282
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 ffff880191f70f40
which belongs to the cache kvm_vcpu(17:syz3) of size 23872
The buggy address is located 22432 bytes inside of
23872-byte region [ffff880191f70f40, ffff880191f76c80)
The buggy address belongs to the page:
page:ffffea000647dc00 count:1 mapcount:0 mapping:ffff8801b4ea0c80 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea00064da208 ffffea00066ad408 ffff8801b4ea0c80
raw: 0000000000000000 ffff880191f70f40 0000000100000001 ffff8801d055a1c0
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff8801d055a1c0

Memory state around the buggy address:
ffff880191f76580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff880191f76600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

ffff880191f76680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

^
ffff880191f76700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff880191f76780: 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.
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Next message: Cornelia Huck: "Re: [PATCH v9 12/22] s390: vfio-ap: sysfs interfaces to configure control domains"
Previous message: syzbot: "BUG: corrupted list in __loaded_vmcs_clear"
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