Hello, The following program triggers GPF in kvm_lapic_set_tpr: kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN Modules linked in: CPU: 0 PID: 7683 Comm: syz-executor Not tainted 4.7.0-rc4+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff8800300b46c0 ti: ffff880030e78000 task.ti: ffff880030e78000 RIP: 0010:[<ffffffff811269be>] [<ffffffff811269be>] kvm_lapic_set_tpr+0x5e/0xe0 arch/x86/kvm/lapic.c:1648 RSP: 0018:ffff880030e7fa40 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000016 RSI: 0000000000000000 RDI: 00000000000000b0 RBP: ffff880030e7fa58 R08: ffffed0006142069 R09: ffff880030a102c0 R10: ffff880030a10347 R11: ffffed0006142069 R12: 0000000000000000 R13: ffff880030a10040 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007fc65886c700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc65884b000 CR3: 00000000315cd000 CR4: 00000000000026f0 Stack: ffff880030a10040 0000000000000000 ffff880030a10040 ffff880030e7fa78 ffffffff8109496c 0000000000000001 0000000000000000 ffff880030e7faa0 ffffffff81094a22 ffff880030a10040 1ffff100061cff57 ffff880030e7fb58 Call Trace: [<ffffffff8109496c>] kvm_set_cr8.part.135+0x2c/0xb0 arch/x86/kvm/x86.c:809 [<ffffffff81094a22>] kvm_set_cr8+0x32/0x50 arch/x86/kvm/x86.c:806 [<ffffffff81178dd4>] vmx_vcpu_reset+0x114/0xb60 arch/x86/kvm/vmx.c:4996 [<ffffffff810b91b0>] kvm_vcpu_reset+0x410/0x580 arch/x86/kvm/x86.c:7470 [<ffffffff810b9355>] kvm_arch_vcpu_setup+0x35/0x60 arch/x86/kvm/x86.c:7393 [< inline >] kvm_vm_ioctl_create_vcpu arch/x86/kvm/../../../virt/kvm/kvm_main.c:2355 [<ffffffff8106b9f2>] kvm_vm_ioctl+0x582/0x10d0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2839 [< inline >] vfs_ioctl fs/ioctl.c:43 [<ffffffff818510bc>] do_vfs_ioctl+0x18c/0xff0 fs/ioctl.c:674 [< inline >] SYSC_ioctl fs/ioctl.c:689 [<ffffffff81851faf>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680 [<ffffffff86a96fc0>] entry_SYSCALL_64_fastpath+0x23/0xc1 arch/x86/entry/entry_64.S:207 Code: 92 00 00 00 4d 8b a4 24 60 03 00 00 48 b8 00 00 00 00 00 fc ff df c1 e3 04 0f b6 db 49 8d bc 24 b0 00 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 5e 4d 8b ac 24 b0 00 00 00 48 b8 00 00 00 00 00 RIP [<ffffffff811269be>] kvm_lapic_set_tpr+0x5e/0xe0 arch/x86/kvm/lapic.c:1648 RSP <ffff880030e7fa40> ---[ end trace a57f94f7314716fc ]--- Run in a parallel loop: // autogenerated by syzkaller (http://github.com/google/syzkaller) #include <pthread.h> #include <stdint.h> #include <string.h> #include <sys/syscall.h> #include <unistd.h> long r[9]; void* thr(void* arg) { switch ((long)arg) { case 0: r[0] = syscall(SYS_mmap, 0x20000000ul, 0x16000ul, 0x3ul, 0x32ul, 0xfffffffffffffffful, 0x0ul); break; case 1: r[2] = syscall(SYS_open, "/dev/kvm", 0x540ul, 0, 0, 0); break; case 2: r[3] = syscall(SYS_ioctl, r[2], 0xae01ul, 0x0ul, 0, 0, 0); break; case 3: r[4] = syscall(SYS_ioctl, r[3], 0xae41ul, 0x1ul, 0, 0, 0); break; case 4: r[5] = syscall(SYS_ioctl, r[4], 0xae80ul, 0, 0, 0, 0); break; case 5: r[6] = syscall(SYS_ioctl, r[4], 0xae80ul, 0, 0, 0, 0); break; case 6: r[7] = syscall(SYS_ioctl, r[4], 0xae80ul, 0, 0, 0, 0); break; case 7: r[8] = syscall(SYS_ioctl, r[4], 0x8040ae9ful, 0x20014fe4ul, 0, 0, 0); break; } return 0; } int main() { long i; pthread_t th[8]; syscall(SYS_mmap, 0x20000000ul, 0x16000ul, 0x3ul, 0x32ul, 0xfffffffffffffffful, 0x0ul); srand(getpid()); memset(r, -1, sizeof(r)); for (i = 0; i < 8; i++) { pthread_create(&th[i], 0, thr, (void*)i); } for (i = 0; i < 8; i++) { pthread_join(th[i], 0); } for (i = 0; i < 8; i++) { pthread_create(&th[i], 0, thr, (void*)i); if ((rand() % 2) == 0) usleep(rand() % 10000); } for (i = 0; i < 8; i++) { pthread_join(th[i], 0); } return 0; } On commit 67016f6cdfd079e632bbc49e33178b2d558c120a (Jun 20). -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
