syzbot


general protection fault in __rmap_write_protect

Status: upstream: reported C repro on 2025/09/23 06:55
Bug presence: origin:lts
[Documentation on labels]
Reported-by: syzbot+119f95bed03920df33c4@syzkaller.appspotmail.com
First crash: 9d20h, last: 9d17h
Bug presence (2)
Date Name Commit Repro Result
2025/09/23 lts (merge base) 43bb85222e53 C [report] general protection fault in __rmap_write_protect
2025/09/23 upstream (ToT) cec1e6e5d1ab C Didn't crash

Sample crash report:
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 0xe06ff51e00048600: 0000 [#1] PREEMPT SMP KASAN
KASAN: maybe wild-memory-access in range [0x037fc8f000243000-0x037fc8f000243007]
CPU: 0 PID: 369 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:ffffc90000c37898 EFLAGS: 00010206
RAX: 006ff91e00048600 RBX: 037fc8f000243000 RCX: ffff88810d912780
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 037fc8f000243000
RBP: ffffc90000c378d8 R08: 0000000000000004 R09: 0000000000000003
R10: fffff52000186f28 R11: 1ffff92000186f28 R12: 0000000000000001
R13: 037fc8f000243000 R14: dffffc0000000000 R15: ffff888122510818
FS:  000055558c893500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000fe9008 CR3: 000000011cc0d000 CR4: 00000000003526b0
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: 0033:0x7ff99c46eec9
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:00007fff8d0ec948 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ff99c6c5fa0 RCX: 00007ff99c46eec9
RDX: 0000000000000000 RSI: 000000000000aec7 RDI: 0000000000000004
RBP: 00007ff99c4f1f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff99c6c5fa0 R14: 00007ff99c6c5fa0 R15: 0000000000000002
 </TASK>
Modules linked in:
---[ end trace 91f44d867aff5b79 ]---
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:ffffc90000c37898 EFLAGS: 00010206
RAX: 006ff91e00048600 RBX: 037fc8f000243000 RCX: ffff88810d912780
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 037fc8f000243000
RBP: ffffc90000c378d8 R08: 0000000000000004 R09: 0000000000000003
R10: fffff52000186f28 R11: 1ffff92000186f28 R12: 0000000000000001
R13: 037fc8f000243000 R14: dffffc0000000000 R15: ffff888122510818
FS:  000055558c893500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000fe9008 CR3: 000000011cc0d000 CR4: 00000000003526b0
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

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/23 09:17 android13-5.15-lts 8d934e0056f7 0ac7291c .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in __rmap_write_protect
2025/09/23 06:54 android13-5.15-lts 8d934e0056f7 0ac7291c .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in __rmap_write_protect
* Struck through repros no longer work on HEAD.