syzbot

random: cc1: uninitialized urandom read (8 bytes read)
audit: type=1400 audit(1545927440.299:10): avc:  denied  { map } for  pid=1827 comm="syz-execprog" path="/root/syzkaller-shm460908666" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:file_t:s0 tclass=file permissive=1
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN NOPTI
Modules linked in:
CPU: 0 PID: 6214 Comm: blkid Not tainted 4.14.90+ #29
task: ffff8881c5feaf00 task.stack: ffff8881c5640000
RIP: 0010:bdev_get_queue include/linux/blkdev.h:1015 [inline]
RIP: 0010:bdev_logical_block_size include/linux/blkdev.h:1451 [inline]
RIP: 0010:bd_set_size+0x58/0x320 fs/block_dev.c:1396
RSP: 0018:ffff8881c5647c78 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff11038bfd6e5
RDX: 00000000000000a7 RSI: 0000000000000000 RDI: 0000000000000538
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffffabecab31
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881d53f6780
R13: ffff8881d53f6780 R14: ffff8881c72432c8 R15: ffff8881c72434a8
FS:  00007f3ec9021740(0000) GS:ffff8881dba00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000073c000 CR3: 00000001c69e4002 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 loop_clr_fd+0x465/0xac0 drivers/block/loop.c:1057
 __lo_release drivers/block/loop.c:1618 [inline]
 lo_release+0xfd/0x190 drivers/block/loop.c:1636
 __blkdev_put+0x526/0x6e0 fs/block_dev.c:1783
 blkdev_close+0x86/0xb0 fs/block_dev.c:1855
 __fput+0x25e/0x6f0 fs/file_table.c:210
 task_work_run+0x116/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x12e/0x150 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
 do_syscall_64+0x35d/0x4b0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f3ec89292b0
RSP: 002b:00007ffdc2ebba98 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f3ec89292b0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000028 R09: 0000000001680000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001f8a030
R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000005
Code: 03 80 3c 02 00 0f 85 a4 02 00 00 49 8b 9c 24 e0 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bb 38 05 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 70 02 00 00 4d 8d 6c 24 08 48 8b 9b 38 05 00 
RIP: bdev_get_queue include/linux/blkdev.h:1015 [inline] RSP: ffff8881c5647c78
RIP: bdev_logical_block_size include/linux/blkdev.h:1451 [inline] RSP: ffff8881c5647c78
RIP: bd_set_size+0x58/0x320 fs/block_dev.c:1396 RSP: ffff8881c5647c78
---[ end trace e81a8b7ee0bd5f63 ]---