================================================================== BUG: KASAN: use-after-free in __fire_sched_in_preempt_notifiers kernel/sched/core.c:2481 [inline] BUG: KASAN: use-after-free in fire_sched_in_preempt_notifiers kernel/sched/core.c:2487 [inline] BUG: KASAN: use-after-free in finish_task_switch+0x544/0x870 kernel/sched/core.c:2679 Read of size 8 at addr ffff880193b21d18 by task syz-executor3/4885 CPU: 0 PID: 4885 Comm: syz-executor3 Not tainted 4.18.0-rc8-next-20180806+ #32 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 __fire_sched_in_preempt_notifiers kernel/sched/core.c:2481 [inline] fire_sched_in_preempt_notifiers kernel/sched/core.c:2487 [inline] finish_task_switch+0x544/0x870 kernel/sched/core.c:2679 context_switch kernel/sched/core.c:2826 [inline] __schedule+0x884/0x1ec0 kernel/sched/core.c:3471 preempt_schedule_common+0x22/0x60 kernel/sched/core.c:3595 _cond_resched+0x1d/0x30 kernel/sched/core.c:4961 zap_pmd_range mm/memory.c:1449 [inline] zap_pud_range mm/memory.c:1476 [inline] zap_p4d_range mm/memory.c:1497 [inline] unmap_page_range+0x11d2/0x2100 mm/memory.c:1518 unmap_single_vma+0x1a0/0x310 mm/memory.c:1563 unmap_vmas+0x125/0x200 mm/memory.c:1593 exit_mmap+0x2c2/0x590 mm/mmap.c:3093 __mmput kernel/fork.c:1003 [inline] mmput+0x265/0x620 kernel/fork.c:1024 exit_mm kernel/exit.c:544 [inline] do_exit+0xec6/0x2760 kernel/exit.c:856 do_group_exit+0x177/0x440 kernel/exit.c:972 get_signal+0x88e/0x1970 kernel/signal.c:2467 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e5/0x380 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x456cb9 Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f24f212ecf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00000000009300a8 RCX: 0000000000456cb9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000009300a8 RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000009300ac R13: 00007ffe23b48b7f R14: 00007f24f212f9c0 R15: 0000000000000000 Allocated by task 4885: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554 kmem_cache_zalloc include/linux/slab.h:697 [inline] vmx_create_vcpu+0xcf/0x2980 arch/x86/kvm/vmx.c:10656 kvm_arch_vcpu_create+0xe5/0x220 arch/x86/kvm/x86.c:8398 kvm_vm_ioctl_create_vcpu arch/x86/kvm/../../../virt/kvm/kvm_main.c:2476 [inline] kvm_vm_ioctl+0x488/0x1d80 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2977 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 __do_sys_ioctl fs/ioctl.c:709 [inline] __se_sys_ioctl fs/ioctl.c:707 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 4884: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x86/0x2d0 mm/slab.c:3756 vmx_free_vcpu+0x26b/0x300 arch/x86/kvm/vmx.c:10650 kvm_arch_vcpu_free arch/x86/kvm/x86.c:8384 [inline] kvm_free_vcpus arch/x86/kvm/x86.c:8833 [inline] kvm_arch_destroy_vm+0x365/0x7c0 arch/x86/kvm/x86.c:8930 kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:752 [inline] kvm_put_kvm+0x73f/0x1060 arch/x86/kvm/../../../virt/kvm/kvm_main.c:773 kvm_vcpu_release+0x7b/0xa0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2407 __fput+0x376/0x8a0 fs/file_table.c:279 ____fput+0x15/0x20 fs/file_table.c:312 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff880193b21d00 which belongs to the cache kvm_vcpu of size 23808 The buggy address is located 24 bytes inside of 23808-byte region [ffff880193b21d00, ffff880193b27a00) The buggy address belongs to the page: page:ffffea00064ec800 count:1 mapcount:0 mapping:ffff8801d4c35dc0 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffffea000657de08 ffff8801d4c29648 ffff8801d4c35dc0 raw: 0000000000000000 ffff880193b21d00 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff880193b21c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff880193b21c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff880193b21d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff880193b21d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff880193b21e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================