=============================
WARNING: suspicious RCU usage
4.15.0-rc2+ #149 Not tainted
-----------------------------
page:000000002d86e974 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 0000000100000001 ffff8801bf200720 0000000000000000
page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)
------------[ cut here ]------------
kernel BUG at ./include/linux/mm.h:483!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 1757 Comm: syz-executor5 Not tainted 4.15.0-rc2+ #149
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:put_page_testzero include/linux/mm.h:483 [inline]
RIP: 0010:__free_pages+0x118/0x150 mm/page_alloc.c:4284
RSP: 0018:ffff8801a2fdf790 EFLAGS: 00010203
RAX: 0000000000000000 RBX: ffffea00068bf7c0 RCX: 0000000000000000
RDX: 00000000001f0100 RSI: 1ffff1003b138535 RDI: ffffed00345fbee0
RBP: ffff8801a2fdf820 R08: 1ffff100345fbe16 R09: 0000000000000000
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff100345fbef3
R13: 1ffff100345fbef7 R14: 0000000000000000 R15: ffff8801a2fdf7f8
FS:  00007f172b624700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020e83000 CR3: 00000001d96c5000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 free_pages+0x51/0x90 mm/page_alloc.c:4298
 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_encrypt_blkcipher+0x213/0x310 crypto/skcipher.c:631
 crypto_skcipher_encrypt include/crypto/skcipher.h:445 [inline]
 _skcipher_recvmsg crypto/algif_skcipher.c:144 [inline]
 skcipher_recvmsg+0x9e8/0xf20 crypto/algif_skcipher.c:165
 sock_recvmsg_nosec net/socket.c:809 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:816
 sock_read_iter+0x361/0x560 net/socket.c:893
 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: 0033:0x452a39
RSP: 002b:00007f172b623c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452a39
RDX: 0000000000000047 RSI: 0000000020e1c000 RDI: 0000000000000017
RBP: 0000000000000554 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f6080
R13: 00000000ffffffff R14: 00007f172b6246d4 R15: 0000000000000001
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 40 32 30 85 48 89 df e8 b8 61 0c 00 <0f> 0b 4c 89 ef 89 b5 74 ff ff ff e8 b8 f3 19 00 8b b5 74 ff ff 
RIP: put_page_testzero include/linux/mm.h:483 [inline] RSP: ffff8801a2fdf790
RIP: __free_pages+0x118/0x150 mm/page_alloc.c:4284 RSP: ffff8801a2fdf790
---[ end trace 36448c6753d35c87 ]---