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BUG: KASAN: use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
BUG: KASAN: use-after-free in do_raw_spin_lock+0x1e0/0x220 kernel/locking/spinlock_debug.c:112
Read of size 4 at addr ffff8801c9c2fd24 by task syz-executor6/5473

CPU: 1 PID: 5473 Comm: syz-executor6 Not tainted 4.15.0+ #218
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:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23b/0x360 mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
 do_raw_spin_lock+0x1e0/0x220 kernel/locking/spinlock_debug.c:112
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:117 [inline]
 _raw_spin_lock_irqsave+0x9e/0xc0 kernel/locking/spinlock.c:152
 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+0x327/0x7e0 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x199/0x270 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_32_irqs_on arch/x86/entry/common.c:336 [inline]
 do_fast_syscall_32+0xbe8/0xfa1 arch/x86/entry/common.c:392
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129
RIP: 0023:0xf7f41c79
RSP: 002b:00000000f771c09c EFLAGS: 00000286 ORIG_RAX: 000000000000014a
RAX: 0000000000000016 RBX: 0000000000000015 RCX: 0000000000000016
RDX: 0000000000000000 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 5467:
 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:552
 kmem_cache_alloc_trace+0x136/0x740 mm/slab.c:3607
 kmalloc include/linux/slab.h:512 [inline]
 kzalloc include/linux/slab.h:701 [inline]
 binder_get_thread+0x1cf/0x870 drivers/android/binder.c:4279
 binder_poll+0x8c/0x390 drivers/android/binder.c:4393
 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
 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 do_fast_syscall_32+0x3ee/0xfa1 arch/x86/entry/common.c:392
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129

Freed by task 5467:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3485 [inline]
 kfree+0xd9/0x260 mm/slab.c:3800
 binder_free_thread drivers/android/binder.c:4306 [inline]
 binder_thread_dec_tmpref+0x27f/0x310 drivers/android/binder.c:1879
 binder_thread_release+0x4a1/0x6b0 drivers/android/binder.c:4382
 binder_ioctl+0xc02/0x1417 drivers/android/binder.c:4599
 C_SYSC_ioctl fs/compat_ioctl.c:1461 [inline]
 compat_SyS_ioctl+0x151/0x2a30 fs/compat_ioctl.c:1407
 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 do_fast_syscall_32+0x3ee/0xfa1 arch/x86/entry/common.c:392
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129

The buggy address belongs to the object at ffff8801c9c2fc80
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 164 bytes inside of
 512-byte region [ffff8801c9c2fc80, ffff8801c9c2fe80)
The buggy address belongs to the page:
page:ffffea0007270bc0 count:1 mapcount:0 mapping:ffff8801c9c2f000 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c9c2f000 0000000000000000 0000000100000006
raw: ffffea0006c71d60 ffffea0006c72160 ffff8801db000940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c9c2fc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801c9c2fc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801c9c2fd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff8801c9c2fd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801c9c2fe00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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