==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x2d5e/0x3fb0 kernel/locking/lockdep.c:3562
Read of size 8 at addr ffff88809616d1a8 by task syz-executor.3/3319

CPU: 0 PID: 3319 Comm: syz-executor.3 Not tainted 5.1.0-rc5-next-20190418 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:316
 kasan_report+0x12/0x20 mm/kasan/common.c:620
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 __lock_acquire+0x2d5e/0x3fb0 kernel/locking/lockdep.c:3562
 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4200
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
 spin_lock include/linux/spinlock.h:338 [inline]
 shmem_fault+0x5b4/0x760 mm/shmem.c:2032
 __do_fault+0x116/0x4e0 mm/memory.c:3126
 do_shared_fault mm/memory.c:3591 [inline]
 do_fault mm/memory.c:3669 [inline]
 handle_pte_fault mm/memory.c:3896 [inline]
 __handle_mm_fault+0x2a93/0x3ec0 mm/memory.c:4020
 handle_mm_fault+0x3b7/0xa90 mm/memory.c:4057
 do_user_addr_fault arch/x86/mm/fault.c:1476 [inline]
 __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1542
 do_page_fault+0x71/0x581 arch/x86/mm/fault.c:1573
 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1142
RIP: 0033:0x401abc
Code: ff 01 64 48 8b 3c 25 00 00 00 00 48 81 c7 08 ff ff ff e8 87 f5 01 00 85 c0 75 13 48 63 44 24 04 48 8b 54 24 18 48 8b 4c 24 08 <48> 89 0c c2 64 f0 83 2c 25 d0 ff ff ff 01 64 f0 83 04 25 d0 ff ff
RSP: 002b:00007fbaf0a16010 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00007fbaf0a164f0 RCX: 00008f0000509120
RDX: 0000000020003800 RSI: 0000000000000000 RDI: 00007fbaf0a18608
RBP: 0000000020003800 R08: 0000000000000090 R09: 0000000000000005
R10: 00000000000000b3 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000020000000 R14: 00000000004dd6b8 R15: 00000000ffffffff

Allocated by task 3319:
 save_stack+0x45/0xb0 mm/kasan/common.c:76
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:495 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:468
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:503
 slab_post_alloc_hook mm/slab.h:437 [inline]
 slab_alloc mm/slab.c:3356 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3518
 shmem_alloc_inode+0x1c/0x50 mm/shmem.c:3628
 alloc_inode+0x66/0x190 fs/inode.c:210
 new_inode_pseudo+0x19/0xf0 fs/inode.c:903
 new_inode+0x1f/0x40 fs/inode.c:932
 shmem_get_inode+0x84/0x7e0 mm/shmem.c:2226
 __shmem_file_setup.part.0+0x1e2/0x2b0 mm/shmem.c:3985
 __shmem_file_setup mm/shmem.c:3979 [inline]
 shmem_kernel_file_setup mm/shmem.c:4015 [inline]
 shmem_zero_setup+0xe2/0x474 mm/shmem.c:4059
 mmap_region+0x13f7/0x1750 mm/mmap.c:1803
 do_mmap+0x924/0x1090 mm/mmap.c:1560
 do_mmap_pgoff include/linux/mm.h:2391 [inline]
 vm_mmap_pgoff+0x1c5/0x230 mm/util.c:362
 ksys_mmap_pgoff+0xf7/0x630 mm/mmap.c:1610
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline]
 __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91
 do_syscall_64+0x103/0x670 arch/x86/entry/common.c:298
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 3313:
 save_stack+0x45/0xb0 mm/kasan/common.c:76
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:457
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:465
 __cache_free mm/slab.c:3462 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3728
 shmem_destroy_callback+0x6e/0xc0 mm/shmem.c:3639
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch kernel/rcu/tree.c:2092 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline]
 rcu_core+0xbac/0x1510 kernel/rcu/tree.c:2291
 __do_softirq+0x266/0x95a kernel/softirq.c:293

The buggy address belongs to the object at ffff88809616d000
 which belongs to the cache shmem_inode_cache(65:syz3) of size 1192
The buggy address is located 424 bytes inside of
 1192-byte region [ffff88809616d000, ffff88809616d4a8)
The buggy address belongs to the page:
page:ffffea0002585b40 count:1 mapcount:0 mapping:ffff88808909d040 index:0xffff88809616dffd
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00025e0a08 ffffea000128a588 ffff88808909d040
raw: ffff88809616dffd ffff88809616d000 0000000100000003 ffff888059bac5c0
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff888059bac5c0

Memory state around the buggy address:
 ffff88809616d080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809616d100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88809616d180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff88809616d200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809616d280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================