=============================
WARNING: suspicious RCU usage
4.15.0-rc1+ #133 Not tainted
-----------------------------
page:000000006ccc40fd count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000
page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)
------------[ cut here ]------------
kernel BUG at ./include/linux/mm.h:482!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 29409 Comm: syz-executor2 Not tainted 4.15.0-rc1+ #133
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: 00000000bdb76ce5 task.stack: 00000000cd3e1747
RIP: 0010:put_page_testzero include/linux/mm.h:482 [inline]
RIP: 0010:__free_pages+0x118/0x150 mm/page_alloc.c:4288
RSP: 0018:ffff8801c8a3f790 EFLAGS: 00010203
RAX: 0000000000000000 RBX: ffffea0007228fc0 RCX: 0000000000000000
RDX: 00000000001f0100 RSI: 1ffff10033b02d4d RDI: ffffed0039147ee0
RBP: ffff8801c8a3f820 R08: 1ffff10039147e16 R09: 0000000000000000
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff10039147ef3
R13: 1ffff10039147ef7 R14: 0000000000000000 R15: ffff8801c8a3f7f8
FS:  00007fcaeb1ee700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f39c24132b8 CR3: 00000001ccd5b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 free_pages+0x51/0x90 mm/page_alloc.c:4302
 blkcipher_walk_done+0x767/0xde0 crypto/blkcipher.c:141
 encrypt+0x50a/0xaf0 crypto/salsa20_generic.c:208
 skcipher_crypt_blkcipher crypto/skcipher.c:622 [inline]
 skcipher_decrypt_blkcipher+0x213/0x310 crypto/skcipher.c:640
 crypto_skcipher_decrypt include/crypto/skcipher.h:463 [inline]
 _skcipher_recvmsg crypto/algif_skcipher.c:144 [inline]
 skcipher_recvmsg+0xa54/0xf20 crypto/algif_skcipher.c:165
 sock_recvmsg_nosec net/socket.c:805 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:812
 sock_read_iter+0x361/0x560 net/socket.c:889
 call_read_iter include/linux/fs.h:1766 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 __vfs_read+0x6ad/0xa00 fs/read_write.c:413
 vfs_read+0x124/0x360 fs/read_write.c:447
 SYSC_read fs/read_write.c:573 [inline]
 SyS_read+0xef/0x220 fs/read_write.c:566
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x4529d9
RSP: 002b:00007fcaeb1edc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 00000000004529d9
RDX: 00000000000000f5 RSI: 0000000020f73f0b RDI: 0000000000000018
RBP: 0000000000000141 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006eeeb8
R13: 00000000ffffffff R14: 00007fcaeb1ee6d4 R15: 000000000000000a
Code: 20 08 00 00 00 00 48 83 c4 68 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 29 f5 ff ff eb cf 48 c7 c6 80 29 30 85 48 89 df e8 a8 60 0c 00 <0f> 0b 4c 89 ef 89 b5 74 ff ff ff e8 e8 f0 19 00 8b b5 74 ff ff 
RIP: put_page_testzero include/linux/mm.h:482 [inline] RSP: ffff8801c8a3f790
RIP: __free_pages+0x118/0x150 mm/page_alloc.c:4288 RSP: ffff8801c8a3f790
---[ end trace b90ce5fb4026a02a ]---