=============================
WARNING: suspicious RCU usage
4.15.0-rc1+ #197 Not tainted
page:ffffea000691d1c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: dead000000000100 dead000000000200 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: 16404 Comm: syz-executor6 Not tainted 4.15.0-rc1+ #197
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801ca1a40c0 task.stack: ffff8801a4740000
RIP: 0010:put_page_testzero include/linux/mm.h:482 [inline]
RIP: 0010:__free_pages+0x118/0x150 mm/page_alloc.c:4288
RSP: 0018:ffff8801a47475e0 EFLAGS: 00010206
RAX: 0000000000000000 RBX: ffffea000691d1c0 RCX: 0000000000000000
RDX: 00000000001f0100 RSI: 1ffff1003943492d RDI: ffffed00348e8eb0
RBP: ffff8801a4747670 R08: 1ffff100348e8de0 R09: 0000000000000000
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff100348e8ebd
R13: 1ffff100348e8ec1 R14: 0000000000000000 R15: ffff8801a4747648
FS:  00007fb12a2d0700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020f3f000 CR3: 00000001c95da000 CR4: 00000000001426f0
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:619 [inline]
 skcipher_decrypt_blkcipher+0x213/0x310 crypto/skcipher.c:637
 crypto_skcipher_decrypt include/crypto/skcipher.h:463 [inline]
 _skcipher_recvmsg crypto/algif_skcipher.c:133 [inline]
 skcipher_recvmsg+0xb06/0xf30 crypto/algif_skcipher.c:164
 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]
 do_iter_readv_writev+0x607/0x7f0 fs/read_write.c:651
 do_iter_read+0x220/0x5b0 fs/read_write.c:895
 vfs_readv+0x121/0x1c0 fs/read_write.c:959
 do_readv+0xfc/0x2a0 fs/read_write.c:992
 SYSC_readv fs/read_write.c:1079 [inline]
 SyS_readv+0x27/0x30 fs/read_write.c:1076
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x4529d9
RSP: 002b:00007fb12a2cfc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 00007fb12a2d0700 RCX: 00000000004529d9
RDX: 0000000000000002 RSI: 0000000020f3f000 RDI: 000000000000001b
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a6f7ff R14: 00007fb12a2d09c0 R15: 0000000000000000
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: ffff8801a47475e0
RIP: __free_pages+0x118/0x150 mm/page_alloc.c:4288 RSP: ffff8801a47475e0
---[ end trace acad69c4cd37292b ]---