kasan: GPF could be caused by NULL-ptr deref or user memory access
9pnet_virtio: no channels available for device ./file0
BUG: spinlock bad magic on CPU#0, syz-executor5/13960
 lock: 0xffff8801ac450018, .magic: dead4eac, .owner: <none>/-1, .owner_cpu: -1
CPU: 0 PID: 13960 Comm: syz-executor5 Not tainted 4.9.81-gd2c57b6 #34
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801c6557840 ffffffff81d94de9 ffff8801ac450018 ffff8801d52c4800
 ffffed0037fd3b40 ffffffff844de160 ffff8801bfe9da00 ffff8801c6557880
 ffffffff812489fd ffffffff81224564 2a3708b100000000 0000000000000000
Call Trace:
 [<ffffffff81d94de9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d94de9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff812489fd>] spin_dump+0x14d/0x280 kernel/locking/spinlock_debug.c:67
 [<ffffffff81248d34>] spin_bug kernel/locking/spinlock_debug.c:75 [inline]
 [<ffffffff81248d34>] debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
 [<ffffffff81248d34>] do_raw_spin_lock+0x174/0x1e0 kernel/locking/spinlock_debug.c:112
 [<ffffffff838b3c46>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:119 [inline]
 [<ffffffff838b3c46>] _raw_spin_lock_irqsave+0x56/0x70 kernel/locking/spinlock.c:159
 [<ffffffff81224564>] remove_wait_queue+0x14/0x40 kernel/sched/wait.c:49
 [<ffffffff8165158f>] ep_remove_wait_queue fs/eventpoll.c:535 [inline]
 [<ffffffff8165158f>] ep_unregister_pollwait.isra.6+0xaf/0x240 fs/eventpoll.c:553
 [<ffffffff81651ff1>] ep_remove+0x41/0x290 fs/eventpoll.c:716
 [<ffffffff81653f95>] eventpoll_release_file+0xc5/0x140 fs/eventpoll.c:940
 [<ffffffff81575a88>] eventpoll_release include/linux/eventpoll.h:61 [inline]
 [<ffffffff81575a88>] __fput+0x5a8/0x6e0 fs/file_table.c:199
 [<ffffffff81575c45>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff81195855>] task_work_run+0x115/0x190 kernel/task_work.c:116
 [<ffffffff8113c2c7>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff8113c2c7>] do_exit+0x7e7/0x2a40 kernel/exit.c:833
 [<ffffffff811429d8>] do_group_exit+0x108/0x320 kernel/exit.c:937
 [<ffffffff81165854>] get_signal+0x4d4/0x14e0 kernel/signal.c:2317
 [<ffffffff81052c87>] do_signal+0x87/0x19f0 arch/x86/kernel/signal.c:807
 [<ffffffff81003a31>] exit_to_usermode_loop+0xe1/0x120 arch/x86/entry/common.c:157
 [<ffffffff810066d0>] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
 [<ffffffff810066d0>] syscall_return_slowpath arch/x86/entry/common.c:260 [inline]
 [<ffffffff810066d0>] do_syscall_64+0x370/0x490 arch/x86/entry/common.c:287
 [<ffffffff838b3dbd>] entry_SYSCALL_64_after_swapgs+0x47/0xc5
9pnet_virtio: no channels available for device ./file0
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 13952 Comm: syz-executor6 Not tainted 4.9.81-gd2c57b6 #34
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d4d68000 task.stack: ffff8801d5090000
RIP: 0010:[<ffffffff8144ef61>]  [<ffffffff8144ef61>] __read_once_size include/linux/compiler.h:243 [inline]
RIP: 0010:[<ffffffff8144ef61>]  [<ffffffff8144ef61>] atomic_read arch/x86/include/asm/atomic.h:26 [inline]
RIP: 0010:[<ffffffff8144ef61>]  [<ffffffff8144ef61>] page_ref_count include/linux/page_ref.h:66 [inline]
RIP: 0010:[<ffffffff8144ef61>]  [<ffffffff8144ef61>] put_page_testzero include/linux/mm.h:450 [inline]
RIP: 0010:[<ffffffff8144ef61>]  [<ffffffff8144ef61>] __free_pages+0x21/0x80 mm/page_alloc.c:3897
RSP: 0018:ffff8801d50979a0  EFLAGS: 00010a07
RAX: dffffc0000000000 RBX: dead4ead00000000 RCX: ffffffff8266840b
RDX: 1bd5a9d5a0000003 RSI: 0000000000000000 RDI: dead4ead0000001c
RBP: ffff8801d50979b0 R08: 0000000000000000 R09: ffffed0037fb1dcd
R10: 0000000000000005 R11: ffffed0037fb1dcc R12: 0000000000000004
R13: 0000000000000020 R14: ffff8801c4d72100 R15: dffffc0000000000
FS:  00007f32a6f2e700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020fd9ff0 CR3: 00000001ba092000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff838b4729 ffff8801c4d72258 ffff8801d5097a10 ffffffff82668431
 ffff8801c4d72270 ffffed00389ae44b ffffed00389ae44e ffff8801c4d72268
 dead4ead00000000 ffff8801c4d72240 0000000000000000 0000000000000000
Call Trace:
 [<ffffffff82668431>] sg_remove_scat.isra.19+0x1c1/0x2d0 drivers/scsi/sg.c:1944
 [<ffffffff826687f5>] sg_finish_rem_req+0x2b5/0x340 drivers/scsi/sg.c:1825
 [<ffffffff8266a686>] sg_read+0xa16/0x1440 drivers/scsi/sg.c:526
 [<ffffffff8156cd01>] do_loop_readv_writev.part.17+0x141/0x1e0 fs/read_write.c:714
 [<ffffffff81570b70>] do_loop_readv_writev fs/read_write.c:880 [inline]
 [<ffffffff81570b70>] do_readv_writev+0x520/0x750 fs/read_write.c:874
 [<ffffffff81570e24>] vfs_readv+0x84/0xc0 fs/read_write.c:898
 [<ffffffff81570f46>] do_readv+0xe6/0x250 fs/read_write.c:924
 [<ffffffff81574437>] SYSC_readv fs/read_write.c:1011 [inline]
 [<ffffffff81574437>] SyS_readv+0x27/0x30 fs/read_write.c:1008
 [<ffffffff81006505>] do_syscall_64+0x1a5/0x490 arch/x86/entry/common.c:282
 [<ffffffff838b3dbd>] entry_SYSCALL_64_after_swapgs+0x47/0xc5
Code: e9 27 fc ff ff 0f 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 53 48 89 fb 48 83 c7 1c 48 89 fa 48 83 ec 08 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 3d 
RIP  [<ffffffff8144ef61>] __read_once_size include/linux/compiler.h:243 [inline]
RIP  [<ffffffff8144ef61>] atomic_read arch/x86/include/asm/atomic.h:26 [inline]
RIP  [<ffffffff8144ef61>] page_ref_count include/linux/page_ref.h:66 [inline]
RIP  [<ffffffff8144ef61>] put_page_testzero include/linux/mm.h:450 [inline]
RIP  [<ffffffff8144ef61>] __free_pages+0x21/0x80 mm/page_alloc.c:3897
 RSP <ffff8801d50979a0>
---[ end trace a2afc0ac54c6959d ]---