syzbot

page:ffffea00025c3ac0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x1fffc0000000000()
raw: 01fffc0000000000 ffffea00024bf988 ffffea00021dd448 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)
------------[ cut here ]------------
kernel BUG at include/linux/mm.h:579!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 7779 Comm: syz-executor379 Not tainted 5.0.0-rc8-next-20190226 #43
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:put_page_testzero include/linux/mm.h:579 [inline]
RIP: 0010:put_page include/linux/mm.h:1025 [inline]
RIP: 0010:generic_pipe_buf_release+0x120/0x160 fs/pipe.c:224
Code: bd ff 4c 89 e7 e8 90 43 db ff e8 bb 29 bd ff 5b 41 5c 41 5d 5d c3 e8 af 29 bd ff 48 c7 c6 20 98 75 87 4c 89 e7 e8 c0 db e4 ff <0f> 0b e8 99 29 bd ff 4d 8d 65 ff e9 3d ff ff ff 48 89 df e8 e8 f8
RSP: 0018:ffff8880a503f920 EFLAGS: 00010293
RAX: ffff88808d2ec6c0 RBX: ffffea00025c3af4 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81982852 RDI: ffffea00025c3af8
RBP: ffff8880a503f938 R08: 000000000000003e R09: ffffed1015d05011
R10: ffffed1015d05010 R11: ffff8880ae828087 R12: ffffea00025c3ac0
R13: 0000000000000000 R14: ffff88809b6e8a40 R15: ffff8880952c4000
FS:  00000000016a0880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020f50f90 CR3: 0000000097b89000 CR4: 00000000001406f0
Call Trace:
 pipe_buf_release include/linux/pipe_fs_i.h:129 [inline]
 iter_file_splice_write+0x7d1/0xbe0 fs/splice.c:759
 do_splice_from fs/splice.c:847 [inline]
 direct_splice_actor+0x126/0x1a0 fs/splice.c:1019
 splice_direct_to_actor+0x369/0x970 fs/splice.c:974
 do_splice_direct+0x1da/0x2a0 fs/splice.c:1062
 do_sendfile+0x597/0xd00 fs/read_write.c:1442
 __do_sys_sendfile64 fs/read_write.c:1503 [inline]
 __se_sys_sendfile64 fs/read_write.c:1489 [inline]
 __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1489
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443d29
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b d8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffc1e47c88 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000443d29
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000003
RBP: 00000000006ce018 R08: 00000000004002e0 R09: 00000000004002e0
R10: 0000000102000300 R11: 0000000000000246 R12: 0000000000401a30
R13: 0000000000401ac0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 9daff95e0e1a45ff ]---
RIP: 0010:put_page_testzero include/linux/mm.h:579 [inline]
RIP: 0010:put_page include/linux/mm.h:1025 [inline]
RIP: 0010:generic_pipe_buf_release+0x120/0x160 fs/pipe.c:224
Code: bd ff 4c 89 e7 e8 90 43 db ff e8 bb 29 bd ff 5b 41 5c 41 5d 5d c3 e8 af 29 bd ff 48 c7 c6 20 98 75 87 4c 89 e7 e8 c0 db e4 ff <0f> 0b e8 99 29 bd ff 4d 8d 65 ff e9 3d ff ff ff 48 89 df e8 e8 f8
RSP: 0018:ffff8880a503f920 EFLAGS: 00010293
RAX: ffff88808d2ec6c0 RBX: ffffea00025c3af4 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81982852 RDI: ffffea00025c3af8
RBP: ffff8880a503f938 R08: 000000000000003e R09: ffffed1015d05011
R10: ffffed1015d05010 R11: ffff8880ae828087 R12: ffffea00025c3ac0
R13: 0000000000000000 R14: ffff88809b6e8a40 R15: ffff8880952c4000
FS:  00000000016a0880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020f50f90 CR3: 0000000097b89000 CR4: 00000000001406f0