syzbot


KCSAN: data-race in emulator_read_write_onepage / install_new_memslots (2)

Status: closed as invalid on 2020/06/18 14:13
Subsystems: kvm
[Documentation on labels]
First crash: 1449d, last: 1425d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in emulator_read_write_onepage / install_new_memslots kvm 2 1602d 1615d 0/26 auto-closed as invalid on 2020/02/23 22:37

Sample crash report:
==================================================================
BUG: KCSAN: data-race in emulator_read_write_onepage / install_new_memslots

write to 0xffff888100d4b000 of 8 bytes by task 16004 on cpu 0:
 install_new_memslots+0xe9/0x130 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1077
 kvm_set_memslot+0x800/0xb70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1153
 __kvm_set_memory_region+0x91c/0xc20 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1300
 kvm_set_memory_region+0x31/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1321
 kvm_vm_ioctl_set_memory_region arch/x86/kvm/../../../virt/kvm/kvm_main.c:1333 [inline]
 kvm_vm_ioctl+0x662/0x18b0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3604
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x101/0x150 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x47/0x60 fs/ioctl.c:770
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888100d4b000 of 8 bytes by task 16009 on cpu 1:
 vcpu_match_mmio_gen arch/x86/kvm/x86.h:183 [inline]
 vcpu_match_mmio_gva arch/x86/kvm/x86.h:202 [inline]
 vcpu_mmio_gva_to_gpa arch/x86/kvm/x86.c:5597 [inline]
 emulator_read_write_onepage+0x1e3/0x740 arch/x86/kvm/x86.c:5722
 emulator_read_write.isra.0+0x15b/0x300 arch/x86/kvm/x86.c:5782
 emulator_read_emulated+0x4a/0x60 arch/x86/kvm/x86.c:5809
 read_emulated arch/x86/kvm/emulate.c:1457 [inline]
 segmented_read+0x172/0x220 arch/x86/kvm/emulate.c:1481
 x86_emulate_insn+0x9c9/0x2840 arch/x86/kvm/emulate.c:5621
 x86_emulate_instruction+0x702/0x11d0 arch/x86/kvm/x86.c:6867
 kvm_mmu_page_fault+0x1c7/0xac0 arch/x86/kvm/mmu/mmu.c:5495
 handle_ept_violation+0x1ce/0x430 arch/x86/kvm/vmx/vmx.c:5196
 vmx_handle_exit+0x1de/0xfe0 arch/x86/kvm/vmx/vmx.c:5980
 vcpu_enter_guest+0xc00/0x3740 arch/x86/kvm/x86.c:8481
 vcpu_run arch/x86/kvm/x86.c:8544 [inline]
 kvm_arch_vcpu_ioctl_run+0x281/0xd60 arch/x86/kvm/x86.c:8766
 kvm_vcpu_ioctl+0x70b/0x9d0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3138
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x101/0x150 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x47/0x60 fs/ioctl.c:770
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16009 Comm: syz-executor.2 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/09 14:23 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 092934c1 .config console log report ci2-upstream-kcsan-gce
2020/05/16 13:37 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 37bccd4e .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.