==================================================================
BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 block/genhd.c:1543
Read of size 8 at addr ffff8801d2e4c0e8 by task syz-executor318/2205

CPU: 0 PID: 2205 Comm: syz-executor318 Not tainted 4.4.174+ #4
 0000000000000000 86bd5c262fd1860d ffff8801d24af730 ffffffff81aad1a1
 0000000000000000 ffffea00074b9200 ffff8801d2e4c0e8 0000000000000008
 0000000000000000 ffff8801d24af768 ffffffff81490120 0000000000000000
Call Trace:
 [<ffffffff81aad1a1>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81aad1a1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff81490120>] print_address_description+0x6f/0x21b mm/kasan/report.c:252
 [<ffffffff81490358>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81490358>] kasan_report mm/kasan/report.c:408 [inline]
 [<ffffffff81490358>] kasan_report.cold+0x8c/0x2be mm/kasan/report.c:393
 [<ffffffff81484ed4>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429
 [<ffffffff81a82965>] disk_unblock_events+0x55/0x60 block/genhd.c:1543
 [<ffffffff8154efcc>] __blkdev_get+0x70c/0xdf0 fs/block_dev.c:1297
 [<ffffffff81551938>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1353
 [<ffffffff8155219a>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1508
 [<ffffffff8149154f>] do_dentry_open+0x38f/0xbd0 fs/open.c:749
 [<ffffffff81494d3b>] vfs_open+0x10b/0x210 fs/open.c:862
 [<ffffffff814c5ddf>] do_last fs/namei.c:3269 [inline]
 [<ffffffff814c5ddf>] path_openat+0x136f/0x4470 fs/namei.c:3406
 [<ffffffff814ccab1>] do_filp_open+0x1a1/0x270 fs/namei.c:3440
 [<ffffffff81495668>] do_sys_open+0x2f8/0x600 fs/open.c:1038
 [<ffffffff8149599d>] SYSC_open fs/open.c:1056 [inline]
 [<ffffffff8149599d>] SyS_open+0x2d/0x40 fs/open.c:1051
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

Allocated by task 2205:
 [<ffffffff8102e3c6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff81483f22>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff81483f22>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff81483f22>] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:616
 [<ffffffff81484197>] kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:601
 [<ffffffff814801a3>] kmem_cache_alloc_trace+0x123/0x2d0 mm/slub.c:2642
 [<ffffffff81a81b50>] kmem_cache_alloc_node_trace include/linux/slab.h:367 [inline]
 [<ffffffff81a81b50>] kmalloc_node include/linux/slab.h:514 [inline]
 [<ffffffff81a81b50>] kzalloc_node include/linux/slab.h:631 [inline]
 [<ffffffff81a81b50>] alloc_disk_node+0x50/0x3c0 block/genhd.c:1282
 [<ffffffff81a81edb>] alloc_disk+0x1b/0x20 block/genhd.c:1274
 [<ffffffff81d436d0>] loop_add+0x380/0x830 drivers/block/loop.c:1857
 [<ffffffff81d440a8>] loop_control_ioctl+0x138/0x2f0 drivers/block/loop.c:1988
 [<ffffffff814d23f7>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff814d23f7>] file_ioctl fs/ioctl.c:470 [inline]
 [<ffffffff814d23f7>] do_vfs_ioctl+0x6e7/0xfa0 fs/ioctl.c:605
 [<ffffffff814d2d3f>] SYSC_ioctl fs/ioctl.c:622 [inline]
 [<ffffffff814d2d3f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

Freed by task 2205:
 [<ffffffff8102e3c6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff81484820>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff81484820>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff81484820>] kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:589
 [<ffffffff81481c44>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff81481c44>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff81481c44>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff81481c44>] kfree+0xf4/0x310 mm/slub.c:3749
 [<ffffffff81a80375>] disk_release+0x255/0x330 block/genhd.c:1118
 [<ffffffff81cf785d>] device_release+0x7d/0x220 drivers/base/core.c:247
 [<ffffffff81ab309c>] kobject_cleanup lib/kobject.c:643 [inline]
 [<ffffffff81ab309c>] kobject_release lib/kobject.c:672 [inline]
 [<ffffffff81ab309c>] kref_sub include/linux/kref.h:73 [inline]
 [<ffffffff81ab309c>] kref_put include/linux/kref.h:98 [inline]
 [<ffffffff81ab309c>] kobject_put+0x14c/0x260 lib/kobject.c:689
 [<ffffffff81a7e013>] put_disk+0x23/0x30 block/genhd.c:1346
 [<ffffffff8154ef2c>] __blkdev_get+0x66c/0xdf0 fs/block_dev.c:1290
 [<ffffffff81551938>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1353
 [<ffffffff8155219a>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1508
 [<ffffffff8149154f>] do_dentry_open+0x38f/0xbd0 fs/open.c:749
 [<ffffffff81494d3b>] vfs_open+0x10b/0x210 fs/open.c:862
 [<ffffffff814c5ddf>] do_last fs/namei.c:3269 [inline]
 [<ffffffff814c5ddf>] path_openat+0x136f/0x4470 fs/namei.c:3406
 [<ffffffff814ccab1>] do_filp_open+0x1a1/0x270 fs/namei.c:3440
 [<ffffffff81495668>] do_sys_open+0x2f8/0x600 fs/open.c:1038
 [<ffffffff8149599d>] SYSC_open fs/open.c:1056 [inline]
 [<ffffffff8149599d>] SyS_open+0x2d/0x40 fs/open.c:1051
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

The buggy address belongs to the object at ffff8801d2e4bb80
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1384 bytes inside of
 2048-byte region [ffff8801d2e4bb80, ffff8801d2e4c380)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
kasan: CONFIG_KASAN_INLINE enabledkasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 1993 Comm: mcstransd Not tainted 4.4.174+ #4
task: ffff8800b866c740 task.stack: ffff8800b85c8000
RIP: 0010:[<ffffffff8117d44a>]  [<ffffffff8117d44a>] entity_before kernel/sched/fair.c:512 [inline]
RIP: 0010:[<ffffffff8117d44a>]  [<ffffffff8117d44a>] __enqueue_entity+0x8a/0x2c0 kernel/sched/fair.c:561
RSP: 0018:ffff8801db707b58  EFLAGS: 00010002
RAX: 050c4c2d8a6cacf4 RBX: 2862616c53656761 RCX: 00000002d782dfdc
RDX: ffff8801db71e928 RSI: ffff8801db71e950 RDI: 2862616c536567a1
RBP: ffff8801db707ba0 R08: ffff8801d5fd0110 R09: ffff8801d5fd0070
R10: ffff8801d5fd0000 R11: ffff8801db71e99c R12: ffffffff82891bf0
R13: dffffc0000000000 R14: ffff8801d5fd0060 R15: 0000000000000000
FS:  00007f33b610e7a0(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001c44c60 CR3: 00000000b85e9000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff81b0abec ffff8801db707ba0 ffffffff8117cedf ffff8801db71e880
 ffff8800b866c7a0 ffff8801db71e928 ffff8801d5fd0060 00000002d7de0212
 dffffc0000000000 ffff8801db707cc8 ffffffff8119f190 ffffffff811bbc03
Call Trace:
 [<ffffffff8119f190>] enqueue_entity kernel/sched/fair.c:3526 [inline]
 [<ffffffff8119f190>] enqueue_task_fair+0x13c0/0xb6c0 kernel/sched/fair.c:4711
 [<ffffffff811638e4>] enqueue_task kernel/sched/core.c:858 [inline]
 [<ffffffff811638e4>] activate_task+0x154/0x280 kernel/sched/core.c:874
 [<ffffffff81164b5e>] ttwu_activate kernel/sched/core.c:1736 [inline]
 [<ffffffff81164b5e>] ttwu_do_activate.constprop.0+0xbe/0x1e0 kernel/sched/core.c:1789
 [<ffffffff81168041>] ttwu_queue kernel/sched/core.c:1934 [inline]
 [<ffffffff81168041>] try_to_wake_up+0x6d1/0x1110 kernel/sched/core.c:2068
 [<ffffffff81168bc5>] wake_up_process+0x15/0x20 kernel/sched/core.c:2142
 [<ffffffff8125ea18>] hrtimer_wakeup+0x48/0x60 kernel/time/hrtimer.c:1482
 [<ffffffff8125fa5e>] __run_hrtimer kernel/time/hrtimer.c:1261 [inline]
 [<ffffffff8125fa5e>] __hrtimer_run_queues+0x34e/0xfc0 kernel/time/hrtimer.c:1325
 [<ffffffff81262756>] hrtimer_interrupt+0x1b6/0x450 kernel/time/hrtimer.c:1359
 [<ffffffff8108a9d6>] local_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:901
 [<ffffffff8271b249>] smp_apic_timer_interrupt+0x79/0xb0 arch/x86/kernel/apic/apic.c:925
 [<ffffffff8271a59d>] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:768
 <EOI> [   42.425948]  [<ffffffff812200c9>] ? console_cont_flush kernel/printk/printk.c:2222 [inline]
 <EOI> [   42.425948]  [<ffffffff812200c9>] ? console_unlock kernel/printk/printk.c:2270 [inline]
 <EOI> [   42.425948]  [<ffffffff812200c9>] ? console_unlock+0x8c9/0xa10 kernel/printk/printk.c:2242
 [<ffffffff812205c2>] vprintk_emit+0x3b2/0x820 kernel/printk/printk.c:1837
 [<ffffffff81220a58>] vprintk+0x28/0x30 kernel/printk/printk.c:1848
 [<ffffffff813afd6f>] printk+0xc2/0xf5 kernel/printk/printk.c:1927
 [<ffffffff810c6e7c>] kasan_die_handler arch/x86/mm/kasan_init_64.c:58 [inline]
 [<ffffffff810c6e7c>] kasan_die_handler.cold+0x11/0x22 arch/x86/mm/kasan_init_64.c:53
 [<ffffffff81137e69>] notifier_call_chain+0xb9/0x1e0 kernel/notifier.c:93
 [<ffffffff81138097>] __atomic_notifier_call_chain+0x87/0x150 kernel/notifier.c:183
 [<ffffffff811392e0>] atomic_notifier_call_chain kernel/notifier.c:193 [inline]
 [<ffffffff811392e0>] notify_die+0xe0/0x160 kernel/notifier.c:549
 [<ffffffff8100ee25>] do_general_protection+0x205/0x2b0 arch/x86/kernel/traps.c:461
 [<ffffffff82719dd5>] general_protection+0x25/0x30 arch/x86/entry/entry_64.S:1063
 [<ffffffff819699ce>] kmem_cache_zalloc include/linux/slab.h:610 [inline]
 [<ffffffff819699ce>] file_alloc_security security/selinux/hooks.c:291 [inline]
 [<ffffffff819699ce>] selinux_file_alloc_security+0xae/0x190 security/selinux/hooks.c:3217
 [<ffffffff8194e3a3>] security_file_alloc+0x73/0xb0 security/security.c:743
 [<ffffffff8149d0fb>] get_empty_filp+0x11b/0x370 fs/file_table.c:128
 [<ffffffff814c4b15>] path_openat+0xa5/0x4470 fs/namei.c:3389
 [<ffffffff814ccab1>] do_filp_open+0x1a1/0x270 fs/namei.c:3440
 [<ffffffff81495668>] do_sys_open+0x2f8/0x600 fs/open.c:1038
 [<ffffffff8149599d>] SYSC_open fs/open.c:1056 [inline]
 [<ffffffff8149599d>] SyS_open+0x2d/0x40 fs/open.c:1051
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
Code: 00 0f 85 16 02 00 00 49 8b 4e 50 41 bf 01 00 00 00 49 bd 00 00 00 00 00 fc ff df eb 03 48 89 c3 48 8d 7b 40 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 05 01 00 00 48 3b 4b 40 4c 8d 63 10 78 07 
RIP  [<ffffffff8117d44a>] entity_before kernel/sched/fair.c:512 [inline]
RIP  [<ffffffff8117d44a>] __enqueue_entity+0x8a/0x2c0 kernel/sched/fair.c:561
 RSP <ffff8801db707b58>
---[ end trace bfe5cf554b5f4b8b ]---