[Android 5.15] general protection fault in __rmap_write_protect

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8d934e0056f7 Merge 5.15.193 into android13-5.15-lts
git tree: android13-5.15-lts
console output: https://syzkaller.appspot.com/x/log.txt?x=129d18e2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=aba6efd42433473
dashboard link: https://syzkaller.appspot.com/bug?extid=119f95bed03920df33c4
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11893534580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=169d18e2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c425ec21539f/disk-8d934e00.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/719bf8e2c482/vmlinux-8d934e00.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6f71fdbe8d3d/bzImage-8d934e00.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+119f95...@syzkaller.appspotmail.com

L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.
general protection fault, probably for non-canonical address 0xe06ff51e0003ea00: 0000 [#1] PREEMPT SMP KASAN
KASAN: maybe wild-memory-access in range [0x037fc8f0001f5000-0x037fc8f0001f5007]
CPU: 1 PID: 372 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rmap_get_first arch/x86/kvm/mmu/mmu.c:1120 [inline]
RIP: 0010:__rmap_write_protect+0x2d/0x3a0 arch/x86/kvm/mmu/mmu.c:1242
Code: e5 41 57 41 56 41 55 41 54 53 48 83 ec 18 41 89 f4 48 89 fb 49 be 00 00 00 00 00 fc ff df e8 ea 91 4f 00 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 b4 0d 8e 00 4c 8b 33 31 ff 4c 89
RSP: 0018:ffffc90000b57898 EFLAGS: 00010206
RAX: 006ff91e0003ea00 RBX: 037fc8f0001f5000 RCX: ffff8881109162c0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 037fc8f0001f5000
RBP: ffffc90000b578d8 R08: 0000000000000004 R09: 0000000000000003
R10: fffff5200016af28 R11: 1ffff9200016af28 R12: 0000000000000001
R13: 037fc8f0001f5000 R14: dffffc0000000000 R15: ffff88812a430818
FS: 00005555780ef500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000fe9008 CR3: 000000010a923000 CR4: 00000000003526a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
kvm_mmu_slot_gfn_write_protect+0x14a/0x270 arch/x86/kvm/mmu/mmu.c:1415
kvm_arch_mmu_enable_log_dirty_pt_masked+0x10c/0x3d0 arch/x86/kvm/mmu/mmu.c:1388
kvm_reset_dirty_gfn+0x19d/0x210 virt/kvm/dirty_ring.c:65
kvm_dirty_ring_reset+0x4a9/0x620 virt/kvm/dirty_ring.c:152
kvm_vm_ioctl_reset_dirty_pages+0x1a3/0x3b0 virt/kvm/kvm_main.c:4368
kvm_vm_ioctl+0x385/0xa80 virt/kvm/kvm_main.c:4643
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0x121/0x1a0 fs/ioctl.c:860
__x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:860
x64_sys_call+0x2f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f0c0e587ec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffca2915eb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f0c0e7defa0 RCX: 00007f0c0e587ec9
RDX: 0000000000000000 RSI: 000000000000aec7 RDI: 0000000000000004
RBP: 00007f0c0e60af91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0c0e7defa0 R14: 00007f0c0e7defa0 R15: 0000000000000002
</TASK>
Modules linked in:
---[ end trace 9a468e75569788de ]---
RIP: 0010:rmap_get_first arch/x86/kvm/mmu/mmu.c:1120 [inline]
RIP: 0010:__rmap_write_protect+0x2d/0x3a0 arch/x86/kvm/mmu/mmu.c:1242
Code: e5 41 57 41 56 41 55 41 54 53 48 83 ec 18 41 89 f4 48 89 fb 49 be 00 00 00 00 00 fc ff df e8 ea 91 4f 00 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 b4 0d 8e 00 4c 8b 33 31 ff 4c 89
RSP: 0018:ffffc90000b57898 EFLAGS: 00010206
RAX: 006ff91e0003ea00 RBX: 037fc8f0001f5000 RCX: ffff8881109162c0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 037fc8f0001f5000
RBP: ffffc90000b578d8 R08: 0000000000000004 R09: 0000000000000003
R10: fffff5200016af28 R11: 1ffff9200016af28 R12: 0000000000000001
R13: 037fc8f0001f5000 R14: dffffc0000000000 R15: ffff88812a430818
FS: 00005555780ef500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000fe9008 CR3: 000000010a923000 CR4: 00000000003526a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: e5 41 in $0x41,%eax
2: 57 push %rdi
3: 41 56 push %r14
5: 41 55 push %r13
7: 41 54 push %r12
9: 53 push %rbx
a: 48 83 ec 18 sub $0x18,%rsp
e: 41 89 f4 mov %esi,%r12d
11: 48 89 fb mov %rdi,%rbx
14: 49 be 00 00 00 00 00 movabs $0xdffffc0000000000,%r14
1b: fc ff df
1e: e8 ea 91 4f 00 call 0x4f920d
23: 48 89 d8 mov %rbx,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 48 89 df mov %rbx,%rdi
34: e8 b4 0d 8e 00 call 0x8e0ded
39: 4c 8b 33 mov (%rbx),%r14
3c: 31 ff xor %edi,%edi
3e: 4c rex.WR
3f: 89 .byte 0x89


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