BUG: unable to handle kernel NULL pointer dereference in pcrypt_aead_serial

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: e6a95d88 Linux 4.14.124
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1794dcdaa00000
kernel config: https://syzkaller.appspot.com/x/.config?x=ab7251aa14ac721d
dashboard link: https://syzkaller.appspot.com/bug?extid=9ebcee0e1fe76a7dd301
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9ebcee...@syzkaller.appspotmail.com

TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
cookies. Check SNMP counters.
input: syz0 as /devices/virtual/input/input28
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: (null)
PGD 9919d067 P4D 9919d067 PUD 96c63067 PMD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
cookies. Check SNMP counters.
Modules linked in:
CPU: 1 PID: 30299 Comm: kworker/1:0 Not tainted 4.14.124 #18
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: pencrypt padata_serial_worker
kobject: 'loop4' (ffff8880a4aa41a0): kobject_uevent_env
task: ffff8880a9da85c0 task.stack: ffff888062fc8000
RIP: 0010: (null)
RSP: 0018:ffff888062fcfc80 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff8880a59d2200 RCX: ffff888062fcfcf0
RDX: 1ffff11014b3a442 RSI: 0000000000000000 RDI: ffff8880a59d2200
RBP: ffff888062fcfc98 R08: ffff8880a9da85c0 R09: 0000000000000002
R10: 0000000000000000 R11: ffff8880a9da85c0 R12: ffff888062fcfd10
R13: ffff8880a66ec99c R14: ffff8880a59d2258 R15: ffff8880a59d2250
FS: 0000000000000000(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000009954e000 CR4: 00000000001406e0
Call Trace:
aead_request_complete include/crypto/internal/aead.h:75 [inline]
pcrypt_aead_serial+0x7e/0xb0 crypto/pcrypt.c:123
padata_serial_worker+0x261/0x400 kernel/padata.c:307
kobject: 'loop4' (ffff8880a4aa41a0): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop2' (ffff8880a4a34960): kobject_uevent_env
process_one_work+0x863/0x1600 kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
kobject: 'loop2' (ffff8880a4a34960): fill_kobj_path: path
= '/devices/virtual/block/loop2'
Code: Bad RIP value.
kobject: 'loop4' (ffff8880a4aa41a0): kobject_uevent_env
RIP: (null) RSP: ffff888062fcfc80
CR2: 0000000000000000
---[ end trace a9d599bf30a9ec78 ]---
kobject: 'loop4' (ffff8880a4aa41a0): fill_kobj_path: path
= '/devices/virtual/block/loop4'


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: e6a95d88 Linux 4.14.124
git tree: linux-4.14.y

console output: https://syzkaller.appspot.com/x/log.txt?x=145548f1a00000

kernel config: https://syzkaller.appspot.com/x/.config?x=ab7251aa14ac721d
dashboard link: https://syzkaller.appspot.com/bug?extid=9ebcee0e1fe76a7dd301
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14ae07c1a00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=109bdc01a00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9ebcee...@syzkaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read)
audit: type=1400 audit(1560197892.998:36): avc: denied { map } for
pid=7204 comm="syz-executor598" path="/root/syz-executor598666960"
dev="sda1" ino=1426 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1

TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
cookies. Check SNMP counters.

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: (null)

PGD 7e4a8067 P4D 7e4a8067 PUD 96606067 PMD 0

Oops: 0010 [#1] PREEMPT SMP KASAN

Modules linked in:
CPU: 0 PID: 3146 Comm: kworker/0:2 Not tainted 4.14.124 #18

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: pencrypt padata_serial_worker

task: ffff88809c3ca6c0 task.stack: ffff88809bc00000
RIP: 0010: (null)
RSP: 0018:ffff88809bc07c80 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff88808055bc80 RCX: ffff88809bc07cf0
RDX: 1ffff110100ab792 RSI: 0000000000000000 RDI: ffff88808055bc80
RBP: ffff88809bc07c98 R08: ffff88809c3ca6c0 R09: 0000000000000002
R10: 0000000000000000 R11: ffff88809c3ca6c0 R12: ffff88809bc07d10
R13: ffff8880a694d41c R14: ffff88808055bcd8 R15: ffff88808055bcd0
FS: 0000000000000000(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000000000000 CR3: 00000000a10d2000 CR4: 00000000001406f0

Call Trace:
aead_request_complete include/crypto/internal/aead.h:75 [inline]
pcrypt_aead_serial+0x7e/0xb0 crypto/pcrypt.c:123
padata_serial_worker+0x261/0x400 kernel/padata.c:307

process_one_work+0x863/0x1600 kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Code: Bad RIP value.
RIP: (null) RSP: ffff88809bc07c80
CR2: 0000000000000000
---[ end trace 5d9f7b2e3912ca28 ]---