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BUG: KASAN: use-after-free in __list_add_valid+0xb1/0xd0 lib/list_debug.c:23
Read of size 8 at addr ffff8801b0ba2710 by task syz-executor2/6768

CPU: 1 PID: 6768 Comm: syz-executor2 Not tainted 4.15.0+ #196
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+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 __list_add_valid+0xb1/0xd0 lib/list_debug.c:23
 __list_add include/linux/list.h:60 [inline]
 list_add include/linux/list.h:79 [inline]
 __add_wait_queue include/linux/wait.h:156 [inline]
 add_wait_queue+0xcf/0x290 kernel/sched/wait.c:30
 vhost_poll_func+0x3d/0x50 drivers/vhost/vhost.c:165
 poll_wait include/linux/poll.h:46 [inline]
 eventfd_poll+0xe8/0x1f0 fs/eventfd.c:123
 vhost_poll_start+0x97/0x1c0 drivers/vhost/vhost.c:212
 vhost_vring_ioctl+0xe28/0x19b0 drivers/vhost/vhost.c:1560
 vhost_net_ioctl+0x9df/0x1910 drivers/vhost/net.c:1320
 vhost_net_compat_ioctl+0x24/0x30 drivers/vhost/net.c:1332
 C_SYSC_ioctl fs/compat_ioctl.c:1473 [inline]
 compat_SyS_ioctl+0x151/0x2a30 fs/compat_ioctl.c:1419
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129
RIP: 0023:0xf7f9dc79
RSP: 002b:00000000f775708c EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000017 RCX: 000000004008af20
RDX: 00000000208ffff8 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6752:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3672 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3679
 kmalloc_node include/linux/slab.h:541 [inline]
 kvmalloc_node+0x64/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:541 [inline]
 vhost_net_open+0x27/0x670 drivers/vhost/net.c:902
 misc_open+0x382/0x500 drivers/char/misc.c:154
 chrdev_open+0x257/0x730 fs/char_dev.c:417
 do_dentry_open+0x667/0xd40 fs/open.c:752
 vfs_open+0x107/0x220 fs/open.c:866
 do_last fs/namei.c:3379 [inline]
 path_openat+0x1151/0x3530 fs/namei.c:3519
 do_filp_open+0x25b/0x3b0 fs/namei.c:3554
 do_sys_open+0x502/0x6d0 fs/open.c:1059
 C_SYSC_openat fs/open.c:1105 [inline]
 compat_SyS_openat+0x2d/0x40 fs/open.c:1103
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129

Freed by task 6752:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3488 [inline]
 kfree+0xd6/0x260 mm/slab.c:3803
 kvfree+0x36/0x60 mm/util.c:416
 vhost_net_release+0x159/0x190 drivers/vhost/net.c:1012
 __fput+0x327/0x7e0 fs/file_table.c:210
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x199/0x270 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x296/0x310 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:264 [inline]
 do_syscall_32_irqs_on arch/x86/entry/common.c:333 [inline]
 do_fast_syscall_32+0xbfd/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129

The buggy address belongs to the object at ffff8801b0ba2480
 which belongs to the cache kmalloc-65536 of size 65536
The buggy address is located 656 bytes inside of
 65536-byte region [ffff8801b0ba2480, ffff8801b0bb2480)
The buggy address belongs to the page:
page:ffffea0006c2e800 count:1 mapcount:0 mapping:ffff8801b0ba2480 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801b0ba2480 0000000000000000 0000000100000001
raw: ffffea000749d820 ffffea0006c13820 ffff8801db002500 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b0ba2600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801b0ba2680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801b0ba2700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff8801b0ba2780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801b0ba2800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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