BUG: unable to handle kernel paging request in syscall_return

BUG: unable to handle kernel paging request in syscall_return_slowpath
Status: upstream: reported C repro on 2020/05/04 10:54
Reported-by: syzbot+3231e7d48f1538976553@syzkaller.appspotmail.com
First crash: 30d, last: 8h22m

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

Sample crash report:

BUG: unable to handle page fault for address: fffffffff8778570
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 927c067 P4D 927c067 PUD 927e067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 7070 Comm: syz-executor231 Not tainted 5.7.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:0xfffffffff8778570
Code: Bad RIP value.
RSP: 0018:ffffc90001627f00 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000000004000 RCX: ffff888092d64280
RDX: ffff888092d64280 RSI: 0000000000000200 RDI: 0000000000000000
RBP: 0000000000000200 R08: ffffffff8100848d R09: fffffbfff16e6e11
R10: fffffbfff16e6e11 R11: 0000000000000000 R12: 1ffff110125ac850
R13: dffffc0000000000 R14: ffff888092d64280 R15: ffff888092d64280
FS:  0000000001be0880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffff8778546 CR3: 00000000a82d6000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 syscall_return_slowpath+0x9b/0x420 arch/x86/entry/common.c:266
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
Modules linked in:
CR2: fffffffff8778570
---[ end trace 8e914c2fec746223 ]---
RIP: 0010:0xfffffffff8778570
Code: Bad RIP value.
RSP: 0018:ffffc90001627f00 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000000004000 RCX: ffff888092d64280
RDX: ffff888092d64280 RSI: 0000000000000200 RDI: 0000000000000000
RBP: 0000000000000200 R08: ffffffff8100848d R09: fffffbfff16e6e11
R10: fffffbfff16e6e11 R11: 0000000000000000 R12: 1ffff110125ac850
R13: dffffc0000000000 R14: ffff888092d64280 R15: ffff888092d64280
FS:  0000000001be0880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffff8778546 CR3: 00000000a82d6000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Fix bisection attempts:
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-upstream-kasan-gce-smack-root	2020/06/02 19:45	upstream	f3592877	58ae5e18	.config	log	report	syz	C

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-kasan-gce-smack-root	2020/05/03 18:55	upstream	f66ed1eb	58ae5e18	.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-upstream-kasan-gce-smack-root	2020/05/03 15:42	upstream	f66ed1eb	58ae5e18	.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