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Date:   Fri, 04 Nov 2022 07:54:46 -0700
Message-ID: <00000000000035fba305eca64106@google.com>
Subject: [syzbot] BUG: unable to handle kernel paging request in get_desc
From:   syzbot <syzbot+ffb4f000dc2872c93f62@syzkaller.appspotmail.com>
To:     bp@alien8.de, brgerst@gmail.com, dave.hansen@linux.intel.com,
        hpa@zytor.com, kirill@shutemov.name, linux-kernel@vger.kernel.org,
        mingo@redhat.com, peterz@infradead.org,
        syzkaller-bugs@googlegroups.com, tglx@linutronix.de,
        thomas.lendacky@amd.com, x86@kernel.org
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Hello,

syzbot found the following issue on:

HEAD commit:    81214a573d19 Add linux-next specific files for 20221103
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=132019de880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cdc625e9234bac0
dashboard link: https://syzkaller.appspot.com/bug?extid=ffb4f000dc2872c93f62
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12dd52ca880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5d4dda497754/disk-81214a57.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9658efff160a/vmlinux-81214a57.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3711180f2565/bzImage-81214a57.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ffb4f000dc2872c93f62@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: fffffbc5a1c22e00
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 23ffe4067 P4D 23ffe4067 PUD 13ff2d067 PMD 13ff2c067 PTE 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5368 Comm: syz-executor.2 Not tainted 6.1.0-rc3-next-20221103-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
RIP: 0010:get_desc+0x128/0x460 arch/x86/lib/insn-eval.c:660
Code: de 02 00 00 83 e0 07 38 c2 0f 9e c1 84 d2 0f 95 c0 84 c1 0f 85 c9 02 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 d8 48 c1 e8 03 <0f> b6 0c 10 48 8d 43 07 48 89 c6 48 c1 ee 03 0f b6 14 16 48 89 de
RSP: 0018:ffffc9000431fd08 EFLAGS: 00010a06
RAX: 1fffffc5a1c22e00 RBX: fffffe2d0e117000 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000006
RBP: ffffc9000431fdc0 R08: 0000000000000006 R09: 000000000000007f
R10: 0000000000000000 R11: 0000000000000001 R12: 1ffff92000863fa1
R13: dffffc0000000000 R14: 0000000000000000 R15: 000000000000007f
FS:  00007f250ff0e700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffbc5a1c22e00 CR3: 0000000028c1f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 insn_get_seg_base arch/x86/lib/insn-eval.c:725 [inline]
 insn_get_effective_ip+0x187/0x1f0 arch/x86/lib/insn-eval.c:1476
 fixup_iopl_exception+0xd0/0x190 arch/x86/kernel/traps.c:627
 __exc_general_protection arch/x86/kernel/traps.c:752 [inline]
 exc_general_protection+0x176/0x210 arch/x86/kernel/traps.c:728
 asm_exc_general_protection+0x22/0x30 arch/x86/include/asm/idtentry.h:564
RIP: 0003:0x7f250f3abf8c
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 01 00 00 00 00 00 00 00 <00> 00 00 00 48 00 e0 0e 25 7f 00 00 ff ff ff ff ff ff ff ff 01 00
RSP: 0003:00007f250f3abf80 EFLAGS: 00010e96
RAX: 000000003ac744f0 RBX: 0000000000000000 RCX: 00007f250f3abf88
RDX: 0000000000000038 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007f250f3abf80
R10: 0000000000000000 R11: ffffffff00000b5e R12: 00007f250f3abfb0
R13: 00007f250f360680 R14: 0000000000000038 R15: 000000003acf0fd6
 </TASK>
Modules linked in:
CR2: fffffbc5a1c22e00
---[ end trace 0000000000000000 ]---
RIP: 0010:get_desc+0x128/0x460 arch/x86/lib/insn-eval.c:660
Code: de 02 00 00 83 e0 07 38 c2 0f 9e c1 84 d2 0f 95 c0 84 c1 0f 85 c9 02 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 d8 48 c1 e8 03 <0f> b6 0c 10 48 8d 43 07 48 89 c6 48 c1 ee 03 0f b6 14 16 48 89 de
RSP: 0018:ffffc9000431fd08 EFLAGS: 00010a06
RAX: 1fffffc5a1c22e00 RBX: fffffe2d0e117000 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000006
RBP: ffffc9000431fdc0 R08: 0000000000000006 R09: 000000000000007f
R10: 0000000000000000 R11: 0000000000000001 R12: 1ffff92000863fa1
R13: dffffc0000000000 R14: 0000000000000000 R15: 000000000000007f
FS:  00007f250ff0e700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffbc5a1c22e00 CR3: 0000000028c1f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	de 02                	fiadds (%rdx)
   2:	00 00                	add    %al,(%rax)
   4:	83 e0 07             	and    $0x7,%eax
   7:	38 c2                	cmp    %al,%dl
   9:	0f 9e c1             	setle  %cl
   c:	84 d2                	test   %dl,%dl
   e:	0f 95 c0             	setne  %al
  11:	84 c1                	test   %al,%cl
  13:	0f 85 c9 02 00 00    	jne    0x2e2
  19:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  20:	fc ff df
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	0f b6 0c 10          	movzbl (%rax,%rdx,1),%ecx <-- trapping instruction
  2e:	48 8d 43 07          	lea    0x7(%rbx),%rax
  32:	48 89 c6             	mov    %rax,%rsi
  35:	48 c1 ee 03          	shr    $0x3,%rsi
  39:	0f b6 14 16          	movzbl (%rsi,%rdx,1),%edx
  3d:	48 89 de             	mov    %rbx,%rsi


---
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