==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3098/0x4620 kernel/locking/lockdep.c:3365
Read of size 8 at addr ffff888045cb0d80 by task syz-executor.0/11500

CPU: 0 PID: 11500 Comm: syz-executor.0 Not tainted 4.14.175-syzkaller #0
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+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
 __lock_acquire+0x3098/0x4620 kernel/locking/lockdep.c:3365
 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:160
 remove_wait_queue+0x1d/0x180 kernel/sched/wait.c:50
 ep_remove_wait_queue fs/eventpoll.c:611 [inline]
 ep_unregister_pollwait.isra.0+0x9b/0x350 fs/eventpoll.c:629
 ep_remove+0x48/0x450 fs/eventpoll.c:792
 eventpoll_release_file+0xb9/0x130 fs/eventpoll.c:1020
 eventpoll_release include/linux/eventpoll.h:66 [inline]
 __fput+0x53e/0x790 fs/file_table.c:201
 task_work_run+0x113/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1d6/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c889
RSP: 002b:00007ff02f488c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007ff02f4896d4 RCX: 000000000045c889
RDX: 0000000000000000 RSI: 000000004004743c RDI: 0000000000000003
RBP: 000000000076c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000002cd R14: 00000000004c5230 R15: 000000000076c04c

Allocated by task 11480:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 __do_kmalloc_node mm/slab.c:3682 [inline]
 __kmalloc_node+0x4c/0x70 mm/slab.c:3689
 kmalloc_node include/linux/slab.h:530 [inline]
 kvmalloc_node+0x46/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:531 [inline]
 kvzalloc include/linux/mm.h:539 [inline]
 alloc_netdev_mqs+0x76/0xb70 net/core/dev.c:8097
 ppp_create_interface drivers/net/ppp/ppp_generic.c:3019 [inline]
 ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:864 [inline]
 ppp_ioctl+0x1313/0x221a drivers/net/ppp/ppp_generic.c:600
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 11500:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 kvfree+0x45/0x50 mm/util.c:416
 device_release+0x15f/0x1a0 drivers/base/core.c:833
 kobject_cleanup lib/kobject.c:646 [inline]
 kobject_release lib/kobject.c:675 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x13e/0x1f0 lib/kobject.c:692
 put_device+0x1c/0x30 drivers/base/core.c:2014
 free_netdev+0x26f/0x360 net/core/dev.c:8219
 ppp_destroy_interface drivers/net/ppp/ppp_generic.c:3101 [inline]
 ppp_destroy_interface+0x2d7/0x3b0 drivers/net/ppp/ppp_generic.c:3064
 ppp_release+0x122/0x1a0 drivers/net/ppp/ppp_generic.c:414
 ppp_ioctl+0x52d/0x221a drivers/net/ppp/ppp_generic.c:626
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff888045cb0200
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 2944 bytes inside of
 4096-byte region [ffff888045cb0200, ffff888045cb1200)
The buggy address belongs to the page:
page:ffffea0001172c00 count:1 mapcount:0 mapping:ffff888045cb0200 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff888045cb0200 0000000000000000 0000000100000001
raw: ffffea00023fb0a0 ffffea000118c7a0 ffff88812fe56dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888045cb0c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888045cb0d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888045cb0d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888045cb0e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888045cb0e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================