=============================
WARNING: suspicious RCU usage
4.14.0+ #192 Not tainted
BUG: unable to handle kernel NULL pointer dereference at 0000000000000074
IP: virt_to_cache mm/slab.c:400 [inline]
IP: kfree+0xb2/0x250 mm/slab.c:3802
PGD 1d94ee067 P4D 1d94ee067 PUD 1c0ecd067 PMD 0 
Oops: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 10241 Comm: syz-executor5 Not tainted 4.14.0+ #192
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cf1c0140 task.stack: ffff8801c1118000
RIP: 0010:virt_to_cache mm/slab.c:400 [inline]
RIP: 0010:kfree+0xb2/0x250 mm/slab.c:3802
RSP: 0018:ffff8801c111f750 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8801c111f918 RCX: ffffffffffffffff
RDX: ffffea00070447c0 RSI: 0000000000000000 RDI: ffff8801c111f918
RBP: ffff8801c111f770 R08: ffff8801cfc9a940 R09: ffff8801c16b1e00
R10: ffff8801c111f920 R11: 0000000000000118 R12: 0000000000000286
R13: 0000000000000000 R14: ffff8801c111f918 R15: ffff8801c111f880
FS:  00007f2a40ae8700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000074 CR3: 00000001d1c84000 CR4: 00000000001426f0
Call Trace:
 blkcipher_walk_done+0x72b/0xde0 crypto/blkcipher.c:139
 encrypt+0x20e/0x540 arch/x86/crypto/salsa20_glue.c:79
 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
 skcipher_recvmsg_nokey+0x60/0x80 crypto/algif_skcipher.c:283
 sock_recvmsg_nosec net/socket.c:805 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:812
 ___sys_recvmsg+0x29b/0x630 net/socket.c:2207
 __sys_recvmsg+0xe2/0x210 net/socket.c:2252
 SYSC_recvmsg net/socket.c:2264 [inline]
 SyS_recvmsg+0x2d/0x50 net/socket.c:2259
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452879
RSP: 002b:00007f2a40ae7be8 EFLAGS: 00000212 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 0000000000758190 RCX: 0000000000452879
RDX: 0000000000002000 RSI: 0000000020222fc8 RDI: 0000000000000016
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a6f7ff R14: 00007f2a40ae89c0 R15: 0000000000000002
Code: c2 48 b8 00 00 00 00 00 ea ff ff 48 89 df 48 c1 ea 0c 48 c1 e2 06 48 01 c2 48 8b 42 20 48 8d 48 ff a8 01 48 0f 45 d1 4c 8b 6a 30 <49> 63 75 74 e8 e5 73 af ff 48 89 de 4c 89 ef 4c 8b 75 08 e8 06 
RIP: virt_to_cache mm/slab.c:400 [inline] RSP: ffff8801c111f750
RIP: kfree+0xb2/0x250 mm/slab.c:3802 RSP: ffff8801c111f750
CR2: 0000000000000074
---[ end trace 11886170e54c1c6e ]---