=============================
WARNING: suspicious RCU usage
4.14.0+ #129 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 1c1992067 P4D 1c1992067 PUD 1cee57067 PMD 0 
Oops: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 20331 Comm: syz-executor5 Not tainted 4.14.0+ #129
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c2e7e240 task.stack: ffff8801d4c40000
RIP: 0010:virt_to_cache mm/slab.c:400 [inline]
RIP: 0010:kfree+0xb2/0x250 mm/slab.c:3802
RSP: 0018:ffff8801d4c47820 EFLAGS: 00010046
RAX: dead000000000100 RBX: ffff8801d4c479e8 RCX: dead0000000000ff
RDX: ffffea00075311c0 RSI: 0000000000000000 RDI: ffff8801d4c479e8
RBP: ffff8801d4c47840 R08: ffffed003b06a014 R09: 0000000000000000
R10: 0000000000000001 R11: ffffed003b06a013 R12: 0000000000000286
R13: 0000000000000000 R14: ffff8801d4c479e8 R15: ffff8801d4c47950
FS:  00007f27ea761700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000074 CR3: 00000001d4466000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 blkcipher_walk_done+0x72b/0xde0 crypto/blkcipher.c:139
 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]
 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: 0033:0x452879
RSP: 002b:00007f27ea760be8 EFLAGS: 00000212 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452879
RDX: 0000000000000093 RSI: 0000000020436000 RDI: 0000000000000018
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a6f7ff R14: 00007f27ea7619c0 R15: 000000000000000c
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: ffff8801d4c47820
RIP: kfree+0xb2/0x250 mm/slab.c:3802 RSP: ffff8801d4c47820
CR2: 0000000000000074
---[ end trace 39529e3d9dce2841 ]---