[syzbot] upstream boot error: BUG: unable to handle kernel paging request in copy_namespaces

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5d6a0f4da927 Merge tag 'for-linus-6.0-rc1b-tag' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1168343d080000
kernel config: https://syzkaller.appspot.com/x/.config?x=f6bcb425ba129b87
dashboard link: https://syzkaller.appspot.com/bug?extid=2984d1b7aef6b51353f0
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2984d1...@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: ffffdc0000000013
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 11826067 P4D 11826067 PUD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 11 Comm: kworker/u4:1 Not tainted 5.19.0-syzkaller-14374-g5d6a0f4da927 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Workqueue: events_unbound call_usermodehelper_exec_work
RIP: 0010:copy_namespaces+0xe8/0x480 kernel/nsproxy.c:154
Code: 0e 5f 2b 00 45 85 ed 0f 84 d4 01 00 00 e8 40 62 2b 00 49 8d bf 98 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 42 03 00 00 4d 8b bf 98 00 00 00 e8 32 ab 15 00
RSP: 0000:ffffc90000107900 EFLAGS: 00010a02
RAX: dffffc0000000000 RBX: ffff888020118000 RCX: 0000000000000000
RDX: 1fffe00000000013 RSI: ffffffff8150a4b0 RDI: ffff000000000098
RBP: ffff000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000808100
R13: 0000000000000001 R14: ffff8880201188a0 R15: ffff000000000000
FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffdc0000000013 CR3: 000000000bc8e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
copy_process+0x305c/0x7090 kernel/fork.c:2259
kernel_clone+0xe7/0xab0 kernel/fork.c:2673
user_mode_thread+0xad/0xe0 kernel/fork.c:2742
call_usermodehelper_exec_work kernel/umh.c:174 [inline]
call_usermodehelper_exec_work+0xcc/0x180 kernel/umh.c:160
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
Modules linked in:
CR2: ffffdc0000000013
---[ end trace 0000000000000000 ]---
RIP: 0010:copy_namespaces+0xe8/0x480 kernel/nsproxy.c:154
Code: 0e 5f 2b 00 45 85 ed 0f 84 d4 01 00 00 e8 40 62 2b 00 49 8d bf 98 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 42 03 00 00 4d 8b bf 98 00 00 00 e8 32 ab 15 00
RSP: 0000:ffffc90000107900 EFLAGS: 00010a02
RAX: dffffc0000000000 RBX: ffff888020118000 RCX: 0000000000000000
RDX: 1fffe00000000013 RSI: ffffffff8150a4b0 RDI: ffff000000000098
RBP: ffff000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000808100
R13: 0000000000000001 R14: ffff8880201188a0 R15: ffff000000000000
FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffdc0000000013 CR3: 000000000bc8e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 5f pop %rdi
1: 2b 00 sub (%rax),%eax
3: 45 85 ed test %r13d,%r13d
6: 0f 84 d4 01 00 00 je 0x1e0
c: e8 40 62 2b 00 callq 0x2b6251
11: 49 8d bf 98 00 00 00 lea 0x98(%r15),%rdi
18: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1f: fc ff df
22: 48 89 fa mov %rdi,%rdx
25: 48 c1 ea 03 shr $0x3,%rdx
* 29: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2d: 0f 85 42 03 00 00 jne 0x375
33: 4d 8b bf 98 00 00 00 mov 0x98(%r15),%r15
3a: e8 32 ab 15 00 callq 0x15ab71


---
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[Guenter Roeck]

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git  fc4d146e8d7d25ef88d409bea1f2e9aff7f30635

[syzbot]

> #syz test https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git

I see the command but can't find the corresponding bug.
Please resend the email to syzbo...@syzkaller.appspotmail.com address
that is the sender of the bug report (also present in the Reported-by tag).

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[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+2984d1...@syzkaller.appspotmail.com

Tested on:

commit: fc4d146e virtio_net: Revert "virtio_net: set the defau..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git
kernel config: https://syzkaller.appspot.com/x/.config?x=3b9175e0879a7749

dashboard link: https://syzkaller.appspot.com/bug?extid=2984d1b7aef6b51353f0
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+2984d1...@syzkaller.appspotmail.com

Tested on:

commit: 568035b0 Linux 6.0-rc1
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git v6.0-rc1

kernel config: https://syzkaller.appspot.com/x/.config?x=3b9175e0879a7749
dashboard link: https://syzkaller.appspot.com/bug?extid=2984d1b7aef6b51353f0
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

patch: https://syzkaller.appspot.com/x/patch.diff?x=11949fc3080000

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.