random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) ================================================================== 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 ffff8801c79482d8 by task syz-executor216/4445 CPU: 0 PID: 4445 Comm: syz-executor216 Not tainted 4.18.0-rc8-next-20180810+ #36 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 schedule+0xfb/0x450 kernel/sched/core.c:3515 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x3f9/0x840 kernel/futex.c:2530 futex_wait+0x45b/0xa20 kernel/futex.c:2645 do_futex+0x336/0x27d0 kernel/futex.c:3527 __do_sys_futex kernel/futex.c:3587 [inline] __se_sys_futex kernel/futex.c:3555 [inline] __x64_sys_futex+0x472/0x6a0 kernel/futex.c:3555 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4468a9 Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 7b 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f34d3e78da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00000000006dbc88 RCX: 00000000004468a9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000006dbc88 RBP: 00000000006dbc80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc8c R13: 0030656c69662f2e R14: 6c75662f7665642f R15: 00000000006dbd6c Allocated by task 4439: 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/0x28b0 arch/x86/kvm/vmx.c:10682 kvm_arch_vcpu_create+0xe5/0x220 arch/x86/kvm/x86.c:8401 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 4423: 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:10676 kvm_arch_vcpu_free arch/x86/kvm/x86.c:8387 [inline] kvm_free_vcpus arch/x86/kvm/x86.c:8836 [inline] kvm_arch_destroy_vm+0x365/0x7c0 arch/x86/kvm/x86.c:8933 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 ffff8801c79482c0 which belongs to the cache kvm_vcpu of size 23808 The buggy address is located 24 bytes inside of 23808-byte region [ffff8801c79482c0, ffff8801c794dfc0) The buggy address belongs to the page: page:ffffea00071e5200 count:1 mapcount:0 mapping:ffff8801d4c35a80 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffffea000721fe08 ffffea0007364208 ffff8801d4c35a80 raw: 0000000000000000 ffff8801c79482c0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c7948180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801c7948200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801c7948280: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8801c7948300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c7948380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================