Hello,
Syzkaller has triggered a kernel WARNING when fuzzing a 4.4 kernel with the following stacktrace. Call Trace: [<ffffffff81989d3d>] __dump_stack lib/dump_stack.c:15 [inline] [<ffffffff81989d3d>] dump_stack+0xbf/0x113 lib/dump_stack.c:51 [<ffffffff813be4aa>] panic+0x1a6/0x361 kernel/panic.c:116 [<ffffffff811c2c00>] __warn+0x168/0x1b0 kernel/panic.c:470 [<ffffffff813be6a1>] warn_slowpath_null+0x3c/0x40 kernel/panic.c:514 [<ffffffff81030f13>] __x86_set_memory_region+0x1c2/0x3ef arch/x86/kvm/x86.c:7792 [<ffffffff81031185>] x86_set_memory_region+0x45/0x5c arch/x86/kvm/x86.c:7838 [<ffffffff810add1e>] vmx_set_tss_addr+0x8c/0x246 arch/x86/kvm/vmx.c:5171 [<ffffffff8103a798>] kvm_vm_ioctl_set_tss_addr arch/x86/kvm/x86.c:3520 [inline] [<ffffffff8103a798>] kvm_arch_vm_ioctl+0x26b/0x17db arch/x86/kvm/x86.c:3788 [<ffffffff81013cb4>] kvm_vm_ioctl+0xb7d/0xbfa arch/x86/kvm/../../../virt/kvm/kvm_main.c:2959 [<ffffffff8149d51a>] vfs_ioctl fs/ioctl.c:43 [inline] [<ffffffff8149d51a>] do_vfs_ioctl+0xcb0/0xd0f fs/ioctl.c:630 [<ffffffff8149d5ea>] SYSC_ioctl fs/ioctl.c:645 [inline] [<ffffffff8149d5ea>] SyS_ioctl+0x71/0xad fs/ioctl.c:636 [<ffffffff832bca35>] tracesys_phase2+0xa3/0xa8
Could the following patch be applied to v4.4.y. The patch is present in v4.9.y. * b21629da120d ("kvm: x86: avoid warning on repeated KVM_SET_TSS_ADDR")
Tests run: * Syzkaller reproducer * Chrome OS tryjobs
Thanks, - Zubin