2017-12-09 19:39 GMT+08:00 Tianyu Lan <lantianyu1986@xxxxxxxxx>: > 2017-12-09 17:15 GMT+08:00 syzbot > <bot+b19026412c772c86fca485fc8342e3490da9c269@xxxxxxxxxxxxxxxxxxxxxxxxx>: >> syzkaller has found reproducer for the following crash on >> ad4dac17f9d563b9e34aab78a34293b10993e9b5 >> 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. >> C reproducer is attached >> syzkaller reproducer is attached. See https://goo.gl/kgGztJ >> for information about syzkaller reproducers >> >> >> kvm: KVM_SET_TSS_ADDR need to be called before entering vcpu >> ================================================================== >> BUG: KASAN: stack-out-of-bounds in write_mmio+0x560/0x600 >> arch/x86/kvm/x86.c:4669 >> Read of size 8 at addr ffff8801c4587220 by task syzkaller601256/3159 >> >> CPU: 1 PID: 3159 Comm: syzkaller601256 Not tainted 4.15.0-rc2-next-20171208+ >> #63 >> 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_load8_noabort+0x14/0x20 mm/kasan/report.c:430 >> write_mmio+0x560/0x600 arch/x86/kvm/x86.c:4669 >> emulator_read_write_onepage+0x45a/0xea0 arch/x86/kvm/x86.c:4739 >> emulator_read_write+0xe7/0x540 arch/x86/kvm/x86.c:4788 >> emulator_write_emulated arch/x86/kvm/x86.c:4825 [inline] >> emulator_fix_hypercall+0x14d/0x1b0 arch/x86/kvm/x86.c:6349 >> em_hypercall+0x5d/0x120 arch/x86/kvm/emulate.c:3705 >> x86_emulate_insn+0x55d/0x3c20 arch/x86/kvm/emulate.c:5498 >> x86_emulate_instruction+0x411/0x1ad0 arch/x86/kvm/x86.c:5756 >> emulate_instruction arch/x86/include/asm/kvm_host.h:1177 [inline] >> handle_exception+0x3d5/0xa20 arch/x86/kvm/vmx.c:5921 >> vmx_handle_exit+0x25d/0x1ce0 arch/x86/kvm/vmx.c:8887 >> vcpu_enter_guest arch/x86/kvm/x86.c:7068 [inline] >> vcpu_run arch/x86/kvm/x86.c:7130 [inline] >> kvm_arch_vcpu_ioctl_run+0x1836/0x5be0 arch/x86/kvm/x86.c:7300 >> kvm_vcpu_ioctl+0x64c/0x1010 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2555 >> vfs_ioctl fs/ioctl.c:46 [inline] >> do_vfs_ioctl+0x1b1/0x1530 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 >> RIP: 0033:0x4435c9 >> RSP: 002b:00007fffdf34ced8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 >> RAX: ffffffffffffffda RBX: 00000000205b3000 RCX: 00000000004435c9 >> RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 >> RBP: 000000000000000b R08: 0000000000000000 R09: 0000000000000002 >> R10: 0000000000000012 R11: 0000000000000202 R12: 00000000205b7e00 >> R13: 00000000205b6e00 R14: 00000000205b7a00 R15: 00000000205b3000 >> >> The buggy address belongs to the page: >> page:000000002e827842 count:0 mapcount:0 mapping: (null) index:0x0 >> flags: 0x2fffc0000000000() >> raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff >> raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000 >> page dumped because: kasan: bad access detected >> >> Memory state around the buggy address: >> ffff8801c4587100: f2 f2 f2 f2 00 f2 f2 f2 f3 f3 f3 f3 00 00 00 00 >> ffff8801c4587180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >>> >>> ffff8801c4587200: f1 f1 f1 f1 03 f2 f2 f2 f3 f3 f3 f3 00 00 00 00 >> >> ^ >> ffff8801c4587280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >> ffff8801c4587300: 00 f1 f1 f1 f1 02 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 >> ================================================================== >> > > This issue seems to be as same as previous pop issue. I will have a look. It is the *(u64 *)val in trace_kvm_mmio() causes the stack-out-of-bounds, I will cook a patch soon. Regards, Wanpeng Li
