BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: __crypto_alg_lookup+0x43/0x190 crypto/api.c:63
PGD 2152aa067 P4D 2152aa067 PUD 2088c2067 PMD 0 
Oops: 0000 [#1] SMP
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 14573 Comm: syz-executor0 Not tainted 4.15.0-rc3-next-20171214+ #67
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__crypto_alg_lookup+0x43/0x190 crypto/api.c:63
RSP: 0018:ffffc900010fbc10 EFLAGS: 00010216
RAX: 0000000000010000 RBX: 0000000000000000 RCX: ffffffff816741f3
RDX: 0000000000000122 RSI: ffffc900036fa000 RDI: ffff880216a63089
RBP: ffffc900010fbc58 R08: 0000000000000001 R09: 0000000000000001
R10: ffffc900010fbbd8 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000002c85 R14: 000000000000240f R15: 000000000000040e
FS:  00007fc29de31700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000020 CR3: 00000001ff20e001 CR4: 00000000001626f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 crypto_alg_lookup+0x31/0x50 crypto/api.c:201
 crypto_larval_lookup.part.8+0x34/0x1c0 crypto/api.c:218
 crypto_larval_lookup crypto/api.c:212 [inline]
 crypto_alg_mod_lookup+0x77/0x120 crypto/api.c:271
 crypto_find_alg crypto/api.c:501 [inline]
 crypto_alloc_tfm+0x67/0x180 crypto/api.c:534
 crypto_alloc_shash+0x2c/0x40 crypto/shash.c:436
 kdf_alloc security/keys/dh.c:99 [inline]
 __keyctl_dh_compute+0xf8/0xa40 security/keys/dh.c:288
 keyctl_dh_compute+0x57/0x81 security/keys/dh.c:434
 SYSC_keyctl security/keys/keyctl.c:1741 [inline]
 SyS_keyctl+0x72/0x2c0 security/keys/keyctl.c:1637
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a09
RSP: 002b:00007fc29de30c58 EFLAGS: 00000212 ORIG_RAX: 00000000000000fa
RAX: ffffffffffffffda RBX: 000000000071bf58 RCX: 0000000000452a09
RDX: 0000000020599000 RSI: 00000000201d5000 RDI: 0000000000000017
RBP: 0000000000000016 R08: 000000002010c000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000212 R12: 00000000006ed2b0
R13: 00000000ffffffff R14: 00007fc29de316d4 R15: 0000000000000002
Code: 89 7d d0 e8 70 61 c4 ff 48 8b 1d 89 df a6 01 48 81 fb 60 21 0e 83 0f 84 4c 01 00 00 c7 45 c4 fe ff ff ff 45 31 e4 e8 4d 61 c4 ff <44> 8b 6b 20 41 f6 c5 60 0f 85 03 01 00 00 e8 3a 61 c4 ff 44 89 
RIP: __crypto_alg_lookup+0x43/0x190 crypto/api.c:63 RSP: ffffc900010fbc10
CR2: 0000000000000020
---[ end trace 69a7a895665cb7dc ]---