BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 5ddc6067 P4D 5ddc6067 PUD 2c440067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 10675 Comm: syz-executor.2 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:252 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x60 kernel/kcov.c:202
Code: c2 00 01 ff 00 74 11 f7 c2 00 01 00 00 74 35 83 b9 04 14 00 00 00 74 2c 8b 91 e0 13 00 00 83 fa 02 75 21 48 8b 91 e8 13 00 00 <48> 8b 32 48 8d 7e 01 8b 89 e4 13 00 00 48 39 cf 73 08 48 89 44 f2
RSP: 0018:ffffc90016fe7970 EFLAGS: 00010246
RAX: ffffffff83b6c99d RBX: ffff8880a340d060 RCX: ffff8880910c25c0
RDX: 0000000000000000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffff8880a340d0b0 R08: ffffffff83b6c917 R09: ffffffff83b6aed7
R10: 0000000000000003 R11: ffff8880910c25c0 R12: 000000000000000a
R13: 93c0deabd5e9915a R14: 0000000000000003 R15: dffffc0000000000
FS:  00007f58513ad700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007ac69000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 mpih_sqr_n+0x2ad/0x5f0 lib/mpi/mpih-mul.c:292
 mpih_sqr_n+0x25c/0x5f0 lib/mpi/mpih-mul.c:289
 mpi_powm+0x11d9/0x2710 lib/mpi/mpi-pow.c:200
 _compute_val crypto/dh.c:39 [inline]
 dh_compute_value+0x218/0x550 crypto/dh.c:178
 crypto_kpp_generate_public_key include/crypto/kpp.h:315 [inline]
 __keyctl_dh_compute+0x9ef/0x1590 security/keys/dh.c:367
 keyctl_dh_compute+0x87/0xb0 security/keys/dh.c:422
 __do_sys_keyctl security/keys/keyctl.c:1881 [inline]
 __se_sys_keyctl+0x4ff/0x830 security/keys/keyctl.c:1777
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca59
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f58513acc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000fa
RAX: ffffffffffffffda RBX: 00000000004f57e0 RCX: 000000000045ca59
RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000017
RBP: 000000000078bf00 R08: 0000000020000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000718 R14: 00000000004ca10f R15: 00007f58513ad6d4
Modules linked in:
CR2: 0000000000000000
---[ end trace d878d14ce2fcc85e ]---
RIP: 0010:__read_once_size include/linux/compiler.h:252 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x60 kernel/kcov.c:202
Code: c2 00 01 ff 00 74 11 f7 c2 00 01 00 00 74 35 83 b9 04 14 00 00 00 74 2c 8b 91 e0 13 00 00 83 fa 02 75 21 48 8b 91 e8 13 00 00 <48> 8b 32 48 8d 7e 01 8b 89 e4 13 00 00 48 39 cf 73 08 48 89 44 f2
RSP: 0018:ffffc90016fe7970 EFLAGS: 00010246
RAX: ffffffff83b6c99d RBX: ffff8880a340d060 RCX: ffff8880910c25c0
RDX: 0000000000000000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffff8880a340d0b0 R08: ffffffff83b6c917 R09: ffffffff83b6aed7
R10: 0000000000000003 R11: ffff8880910c25c0 R12: 000000000000000a
R13: 93c0deabd5e9915a R14: 0000000000000003 R15: dffffc0000000000
FS:  00007f58513ad700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fab85a01020 CR3: 000000007ac69000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400