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BUG: KASAN: use-after-free in __lock_acquire+0x465e/0x47f0 kernel/locking/lockdep.c:3378
Read of size 8 at addr ffff8801cc649d78 by task syzkaller686201/3081

CPU: 1 PID: 3081 Comm: syzkaller686201 Not tainted 4.15.0-rc2-next-20171205+ #59
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
 __lock_acquire+0x465e/0x47f0 kernel/locking/lockdep.c:3378
 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:159
 remove_wait_queue+0x81/0x350 kernel/sched/wait.c:50
 ep_remove_wait_queue fs/eventpoll.c:595 [inline]
 ep_unregister_pollwait.isra.7+0x18c/0x590 fs/eventpoll.c:613
 ep_free+0x13f/0x320 fs/eventpoll.c:830
 ep_eventpoll_release+0x44/0x60 fs/eventpoll.c:862
 __fput+0x333/0x7f0 fs/file_table.c:210
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x199/0x270 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9bb/0x1ae0 kernel/exit.c:869
 do_group_exit+0x149/0x400 kernel/exit.c:972
 SYSC_exit_group kernel/exit.c:983 [inline]
 SyS_exit_group+0x1d/0x20 kernel/exit.c:981
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x442a38
RSP: 002b:00007ffc8858f988 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000442a38
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000006ce018 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a80
R13: 0000000000401b10 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 3081:
 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
 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3614
 kmalloc include/linux/slab.h:516 [inline]
 kzalloc include/linux/slab.h:705 [inline]
 binder_get_thread+0x1cf/0x870 drivers/android/binder.c:4269
 binder_poll+0x8c/0x390 drivers/android/binder.c:4371
 ep_item_poll.isra.10+0xf2/0x320 fs/eventpoll.c:885
 ep_insert+0x6a2/0x1ac0 fs/eventpoll.c:1457
 SYSC_epoll_ctl fs/eventpoll.c:2104 [inline]
 SyS_epoll_ctl+0x12bf/0x1a80 fs/eventpoll.c:1990
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 3081:
 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:3492 [inline]
 kfree+0xca/0x250 mm/slab.c:3807
 binder_free_thread drivers/android/binder.c:4296 [inline]
 binder_thread_dec_tmpref+0x27f/0x310 drivers/android/binder.c:1869
 binder_thread_release+0x27d/0x540 drivers/android/binder.c:4360
 binder_ioctl+0xc05/0x141a drivers/android/binder.c:4577
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:686
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801cc649cc0
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 184 bytes inside of
 512-byte region [ffff8801cc649cc0, ffff8801cc649ec0)
The buggy address belongs to the page:
page:00000000e56948c0 count:1 mapcount:0 mapping:00000000d66a77be index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801cc649040 0000000000000000 0000000100000006
raw: ffffea00073459a0 ffffea0007332de0 ffff8801db000940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cc649c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801cc649c80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8801cc649d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8801cc649d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cc649e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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