BUG: unable to handle kernel NULL pointer dereference in do_syscall

BUG: unable to handle kernel NULL pointer dereference in do_syscall_64 (2)
Status: upstream: reported C repro on 2020/03/06 05:27
Reported-by: syzbot+d6d57d324860c94d5836@syzkaller.appspotmail.com
First crash: 132d, last: 23d

Cause bisection: the bug happens on the oldest tested release
Crash: WARNING in sysfs_warn_dup (log)
Repro: C syz .config

similar bugs (4):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	BUG: unable to handle kernel NULL pointer dereference in do_syscall_64	2	754d	754d	0/17	auto-closed as invalid on 2019/02/22 10:29
linux-4.14	BUG: unable to handle kernel NULL pointer dereference in do_syscall_64	1	255d	254d	0/1	auto-closed as invalid on 2020/02/28 23:04
linux-4.14	BUG: unable to handle kernel NULL pointer dereference in do_syscall_64 (2)	7	53d	90d	0/1	upstream: reported on 2020/04/13 01:23
linux-4.19	BUG: unable to handle kernel NULL pointer dereference in do_syscall_64	3	119d	134d	0/1	upstream: reported on 2020/02/29 09:51

Sample crash report:

IPVS: ftp: loaded support on port[0] = 21
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 962b6067 P4D 962b6067 PUD 9441e067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 7058 Comm: syz-executor367 Not tainted 5.6.0-next-20200406-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 7d 50 48 ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 80
RSP: 0018:ffffc90001657f28 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000023 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8163ea3d RDI: 0000000000000282
RBP: ffffc90001657f58 R08: ffff8880a9156440 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff89949570 R14: 0000000000000000 R15: 0000000000000000
FS:  00000000015f5940(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000962b7000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x4464b0
Code: c0 5b 5d c3 66 0f 1f 44 00 00 8b 04 24 48 83 c4 18 5b 5d c3 66 0f 1f 44 00 00 83 3d 61 cb 29 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 84 20 fc ff c3 48 83 ec 08 e8 5a 43 00 00
RSP: 002b:00007fffeb3290d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000023
RAX: ffffffffffffffda RBX: 00007fffeb329140 RCX: 00000000004464b0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fffeb3290e0
RBP: 0000000000000002 R08: 0000000000000001 R09: 00000000015f5940
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000fb38
R13: 0000000000408a50 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
CR2: 0000000000000000
---[ end trace 07b78701f72ec477 ]---
RIP: 0010:do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 7d 50 48 ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 80
RSP: 0018:ffffc90001657f28 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000023 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8163ea3d RDI: 0000000000000282
RBP: ffffc90001657f58 R08: ffff8880a9156440 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff89949570 R14: 0000000000000000 R15: 0000000000000000
FS:  00000000015f5940(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000962b7000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (9):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-linux-next-kasan-gce-root	2020/04/07 00:24	linux-next	b2e2a818	99a96044	.config	log	report	syz	C	bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-qemu-upstream	2020/06/19 01:41	upstream	435faf5c	bc258b50	.config	log	report			bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-smack-root	2020/05/18 20:16	upstream	45088963	684d3606	.config	log	report			bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-smack-root	2020/05/18 02:14	upstream	b9bbe6ed	37bccd4e	.config	log	report			bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-smack-root	2020/05/16 01:50	upstream	12bf0b63	37bccd4e	.config	log	report			bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-smack-root	2020/05/13 15:30	upstream	24085f70	9a6d42fb	.config	log	report			bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-smack-root	2020/04/19 11:40	upstream	50cc09c1	6dfd45e1	.config	log	report			bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-smack-root	2020/04/19 03:51	upstream	50cc09c1	365fba24	.config	log	report			bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce	2020/03/02 00:18	upstream	63623fd4	c88c7b75	.config	log	report			bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org