From: Paolo Bonzini pbonzini@redhat.com
commit b21629da120dd6145d14dbd6d028e1bba680a92b upstream.
Found by syzkaller:
WARNING: CPU: 3 PID: 15175 at arch/x86/kvm/x86.c:7705 __x86_set_memory_region+0x1dc/0x1f0 [kvm]() CPU: 3 PID: 15175 Comm: a.out Tainted: G W 4.4.6-300.fc23.x86_64 #1 Hardware name: LENOVO 2325F51/2325F51, BIOS G2ET32WW (1.12 ) 05/30/2012 0000000000000286 00000000950899a7 ffff88011ab3fbf0 ffffffff813b542e 0000000000000000 ffffffffa0966496 ffff88011ab3fc28 ffffffff810a40f2 00000000000001fd 0000000000003000 ffff88014fc50000 0000000000000000 Call Trace: [<ffffffff813b542e>] dump_stack+0x63/0x85 [<ffffffff810a40f2>] warn_slowpath_common+0x82/0xc0 [<ffffffff810a423a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa09251cc>] __x86_set_memory_region+0x1dc/0x1f0 [kvm] [<ffffffffa092521b>] x86_set_memory_region+0x3b/0x60 [kvm] [<ffffffffa09bb61c>] vmx_set_tss_addr+0x3c/0x150 [kvm_intel] [<ffffffffa092f4d4>] kvm_arch_vm_ioctl+0x654/0xbc0 [kvm] [<ffffffffa091d31a>] kvm_vm_ioctl+0x9a/0x6f0 [kvm] [<ffffffff81241248>] do_vfs_ioctl+0x298/0x480 [<ffffffff812414a9>] SyS_ioctl+0x79/0x90 [<ffffffff817a04ee>] entry_SYSCALL_64_fastpath+0x12/0x71
Testcase:
#include <unistd.h> #include <sys/ioctl.h> #include <fcntl.h> #include <string.h> #include <linux/kvm.h>
long r[8];
int main() { memset(r, -1, sizeof(r)); r[2] = open("/dev/kvm", O_RDONLY|O_TRUNC); r[3] = ioctl(r[2], KVM_CREATE_VM, 0x0ul); r[5] = ioctl(r[3], KVM_SET_TSS_ADDR, 0x20000000ul); r[7] = ioctl(r[3], KVM_SET_TSS_ADDR, 0x20000000ul); return 0; }
Reported-by: Dmitry Vyukov dvyukov@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Radim Krčmář rkrcmar@redhat.com Cc: Zubin Mithra zsm@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7799,7 +7799,7 @@ int __x86_set_memory_region(struct kvm *
slot = id_to_memslot(slots, id); if (size) { - if (WARN_ON(slot->npages)) + if (slot->npages) return -EEXIST;
/*