[syzbot] [kvm?] WARNING in kvm_mmu_notifier_change_pte

From: syzbot
Date: Wed Dec 13 2023 - 12:30:33 EST

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Hello,

syzbot found the following issue on:

HEAD commit: f2e8a57ee903 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14fdc732e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e56083f7dbe162c2
dashboard link: https://syzkaller.appspot.com/bug?extid=81227d2bd69e9dedb802
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=129d09cae80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10b8afeee80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7b75e59fc59d/disk-f2e8a57e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f853580d61be/vmlinux-f2e8a57e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8c893ce02e2c/bzImage-f2e8a57e.xz

Bisection is inconclusive: the first bad commit could be any of:

d61ea1cb0095 userfaultfd: UFFD_FEATURE_WP_ASYNC
52526ca7fdb9 fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=120b3bdae80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+81227d2bd69e9dedb802@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5067 at arch/x86/kvm/../../../virt/kvm/kvm_main.c:734 kvm_mmu_notifier_change_pte+0x860/0x960 arch/x86/kvm/../../../virt/kvm/kvm_main.c:734
Modules linked in:
CPU: 0 PID: 5067 Comm: syz-executor813 Not tainted 6.7.0-rc4-syzkaller-00358-gf2e8a57ee903 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:kvm_mmu_notifier_change_pte+0x860/0x960 arch/x86/kvm/../../../virt/kvm/kvm_main.c:734
Code: c7 80 16 c2 8a c6 05 61 3e f9 0d 01 e8 29 80 5d 00 e9 80 fa ff ff e8 8f 93 7d 00 90 0f 0b 90 e9 c0 fd ff ff e8 81 93 7d 00 90 <0f> 0b 90 e9 0f f9 ff ff e8 73 93 7d 00 90 0f 0b 90 e9 76 f8 ff ff
RSP: 0018:ffffc900040e73a0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000020537000 RCX: ffffffff8109f33e
RDX: ffff888016fd9dc0 RSI: ffffffff8109fa2f RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000003 R12: ffff88801afd5f00
R13: 0000000020537000 R14: 0000000076630867 R15: ffffffff8109f1d0
FS: 00007f62e85146c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020537000 CR3: 00000000288fa000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__mmu_notifier_change_pte+0x10d/0x1d0 mm/mmu_notifier.c:438
mmu_notifier_change_pte include/linux/mmu_notifier.h:446 [inline]
wp_page_copy mm/memory.c:3197 [inline]
do_wp_page+0x26a7/0x36b0 mm/memory.c:3511
handle_pte_fault mm/memory.c:5055 [inline]
__handle_mm_fault+0x1d7d/0x3d70 mm/memory.c:5180
handle_mm_fault+0x47a/0xa10 mm/memory.c:5345
do_user_addr_fault+0x3d1/0x1000 arch/x86/mm/fault.c:1413
handle_page_fault arch/x86/mm/fault.c:1505 [inline]
exc_page_fault+0x5d/0xc0 arch/x86/mm/fault.c:1561
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0010:rep_movs_alternative+0x4a/0x70 arch/x86/lib/copy_user_64.S:71
Code: 75 f1 c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 <f3> a4 c3 48 89 c8 48 c1 e9 03 83 e0 07 f3 48 a5 89 c1 85 c9 75 b3
RSP: 0018:ffffc900040e7968 EFLAGS: 00050206
RAX: 0000000000000001 RBX: 0000000000001000 RCX: 0000000000000e80
RDX: 0000000000000000 RSI: ffff888010b22180 RDI: 0000000020537000
RBP: 0000000000001000 R08: 0000000000000000 R09: ffffed10021645ff
R10: ffff888010b22fff R11: 0000000000000000 R12: 0000000000536b80
R13: ffffc900040e7d60 R14: ffff888010b22000 R15: 0000000020536e80
copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:133 [inline]
copy_to_user_iter lib/iov_iter.c:25 [inline]
iterate_iovec include/linux/iov_iter.h:51 [inline]
iterate_and_advance2 include/linux/iov_iter.h:247 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
_copy_to_iter+0x4ce/0x11e0 lib/iov_iter.c:186
copy_page_to_iter lib/iov_iter.c:381 [inline]
copy_page_to_iter+0xf1/0x180 lib/iov_iter.c:368
process_vm_rw_pages mm/process_vm_access.c:45 [inline]
process_vm_rw_single_vec mm/process_vm_access.c:117 [inline]
process_vm_rw_core.constprop.0+0x5cd/0xa10 mm/process_vm_access.c:215
process_vm_rw+0x2ff/0x360 mm/process_vm_access.c:283
__do_sys_process_vm_readv mm/process_vm_access.c:295 [inline]
__se_sys_process_vm_readv mm/process_vm_access.c:291 [inline]
__x64_sys_process_vm_readv+0xe2/0x1b0 mm/process_vm_access.c:291
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f62e855c889
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 1d 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f62e85140c8 EFLAGS: 00000216 ORIG_RAX: 0000000000000136
RAX: ffffffffffffffda RBX: 00007f62e85df3e8 RCX: 00007f62e855c889
RDX: 0000000000000002 RSI: 0000000020008400 RDI: 00000000000013ca
RBP: 00007f62e85df3e0 R08: 0000000000000286 R09: 0000000000000000
R10: 0000000020008640 R11: 0000000000000216 R12: 00007f62e85df3ec
R13: 0000000000000000 R14: 00007ffd42ee6360 R15: 00007ffd42ee6448
</TASK>
----------------
Code disassembly (best guess):
0: 75 f1 jne 0xfffffff3
2: c3 ret
3: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1)
a: 00 00 00 00
e: 66 90 xchg %ax,%ax
10: 48 8b 06 mov (%rsi),%rax
13: 48 89 07 mov %rax,(%rdi)
16: 48 83 c6 08 add $0x8,%rsi
1a: 48 83 c7 08 add $0x8,%rdi
1e: 83 e9 08 sub $0x8,%ecx
21: 74 df je 0x2
23: 83 f9 08 cmp $0x8,%ecx
26: 73 e8 jae 0x10
28: eb c9 jmp 0xfffffff3
* 2a: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
2c: c3 ret
2d: 48 89 c8 mov %rcx,%rax
30: 48 c1 e9 03 shr $0x3,%rcx
34: 83 e0 07 and $0x7,%eax
37: f3 48 a5 rep movsq %ds:(%rsi),%es:(%rdi)
3a: 89 c1 mov %eax,%ecx
3c: 85 c9 test %ecx,%ecx
3e: 75 b3 jne 0xfffffff3

---
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Next message: Fabrice Gasnier: "[PATCH v4 2/2] MAINTAINERS: add myself as counter watch events tool maintainer"
Previous message: Sean Christopherson: "Re: [PATCH v10 03/50] KVM: SEV: Do not intercept accesses to MSR_IA32_XSS for SEV-ES guests"
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