On Wed, Dec 20, 2017 at 08:03:02AM -0800, syzbot wrote: > Hello, > > syzkaller hit the following crash on > 7dc9f647127d6955ffacaf51cb6a627b31dceec2 > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > > Unfortunately, I don't have any reproducer for this bug yet. > > > binder: 7432:7451 BC_CLEAR_DEATH_NOTIFICATION invalid ref 0 > ================================================================== > BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:674 > [inline] > BUG: KASAN: use-after-free in preempt_notifier_register+0x1e2/0x210 > kernel/sched/core.c:2513 > Write of size 8 at addr ffff8801bddf0d50 by task syz-executor2/7427 > > CPU: 1 PID: 7427 Comm: syz-executor2 Not tainted 4.15.0-rc4-next-20171220+ > #77 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:17 [inline] > dump_stack+0x194/0x257 lib/dump_stack.c:53 > print_address_description+0x73/0x250 mm/kasan/report.c:252 > kasan_report_error mm/kasan/report.c:351 [inline] > kasan_report+0x25b/0x340 mm/kasan/report.c:409 > __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435 > hlist_add_head include/linux/list.h:674 [inline] > preempt_notifier_register+0x1e2/0x210 kernel/sched/core.c:2513 > vcpu_load+0x27/0x40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:157 > vmx_free_vcpu_nested arch/x86/kvm/vmx.c:9795 [inline] > vmx_free_vcpu+0x11b/0x260 arch/x86/kvm/vmx.c:9809 > kvm_arch_vcpu_free arch/x86/kvm/x86.c:7870 [inline] > kvm_free_vcpus arch/x86/kvm/x86.c:8317 [inline] > kvm_arch_destroy_vm+0x4a2/0x980 arch/x86/kvm/x86.c:8416 > kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:728 [inline] > kvm_put_kvm+0x695/0xde0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:749 > kvm_vm_release+0x42/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:760 > __fput+0x327/0x7e0 fs/file_table.c:209 > ____fput+0x15/0x20 fs/file_table.c:243 > task_work_run+0x199/0x270 kernel/task_work.c:113 > exit_task_work include/linux/task_work.h:22 [inline] > do_exit+0x9bb/0x1ad0 kernel/exit.c:869 > do_group_exit+0x149/0x400 kernel/exit.c:972 > get_signal+0x73f/0x16c0 kernel/signal.c:2337 > do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809 > exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:161 > prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] > syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 > entry_SYSCALL_64_fastpath+0x94/0x96 > RIP: 0033:0x452a09 > RSP: 002b:00007f067fe32ce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca > RAX: 0000000000000000 RBX: 000000000071bec8 RCX: 0000000000452a09 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000071bec8 > RBP: 000000000071bec8 R08: 00000000000003bb R09: 000000000071bea0 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: 0000000000a2f7ff R14: 00007f067fe339c0 R15: 0000000000000000 > > Allocated by task 7447: > save_stack+0x43/0xd0 mm/kasan/kasan.c:447 > set_track mm/kasan/kasan.c:459 [inline] > kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 > kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 > kmem_cache_alloc+0x12e/0x760 mm/slab.c:3545 > kmem_cache_zalloc include/linux/slab.h:695 [inline] > vmx_create_vcpu+0xc4/0x2f20 arch/x86/kvm/vmx.c:9819 > kvm_arch_vcpu_create+0x12c/0x1a0 arch/x86/kvm/x86.c:7884 > kvm_vm_ioctl_create_vcpu arch/x86/kvm/../../../virt/kvm/kvm_main.c:2445 > [inline] > kvm_vm_ioctl+0x48b/0x1c60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2943 > vfs_ioctl fs/ioctl.c:46 [inline] > do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 > SYSC_ioctl fs/ioctl.c:701 [inline] > SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 > entry_SYSCALL_64_fastpath+0x1f/0x96 > > Freed by task 7427: > save_stack+0x43/0xd0 mm/kasan/kasan.c:447 > set_track mm/kasan/kasan.c:459 [inline] > kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 > __cache_free mm/slab.c:3489 [inline] > kmem_cache_free+0x83/0x2a0 mm/slab.c:3747 > vmx_free_vcpu+0x1ee/0x260 arch/x86/kvm/vmx.c:9813 > kvm_arch_vcpu_free arch/x86/kvm/x86.c:7870 [inline] > kvm_free_vcpus arch/x86/kvm/x86.c:8317 [inline] > kvm_arch_destroy_vm+0x4a2/0x980 arch/x86/kvm/x86.c:8416 > kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:728 [inline] > kvm_put_kvm+0x695/0xde0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:749 > kvm_vm_release+0x42/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:760 > __fput+0x327/0x7e0 fs/file_table.c:209 > ____fput+0x15/0x20 fs/file_table.c:243 > task_work_run+0x199/0x270 kernel/task_work.c:113 > exit_task_work include/linux/task_work.h:22 [inline] > do_exit+0x9bb/0x1ad0 kernel/exit.c:869 > do_group_exit+0x149/0x400 kernel/exit.c:972 > get_signal+0x73f/0x16c0 kernel/signal.c:2337 > do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809 > exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:161 > prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] > syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 > entry_SYSCALL_64_fastpath+0x94/0x96 Probably a duplicate of the kvm_arch_vcpu_ioctl_set_sregs() bug: #syz dup: KASAN: use-after-free Read in __schedule
