L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details. BUG: unable to handle page fault for address: ffffffffffffffea #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD ba8f067 P4D ba8f067 PUD ba91067 PMD 0 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 1 PID: 3601 Comm: syz-executor232 Not tainted 6.1.0-rc1-next-20221021-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 RIP: 0010:arch_atomic_fetch_sub arch/x86/include/asm/atomic.h:190 [inline] RIP: 0010:atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:177 [inline] RIP: 0010:__refcount_sub_and_test include/linux/refcount.h:272 [inline] RIP: 0010:__refcount_dec_and_test include/linux/refcount.h:315 [inline] RIP: 0010:refcount_dec_and_test include/linux/refcount.h:333 [inline] RIP: 0010:kref_put include/linux/kref.h:64 [inline] RIP: 0010:eventfd_ctx_put+0x1e/0x110 fs/eventfd.c:112 Code: 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 54 55 48 89 fd 53 bb ff ff ff ff e8 cf a8 8f ff be 04 00 00 00 48 89 ef e8 f2 38 dc ff 0f c1 5d 00 bf 01 00 00 00 89 de e8 81 a5 8f ff 83 fb 01 74 35 RSP: 0018:ffffc90003c1f748 EFLAGS: 00010246 RAX: 0000000000000001 RBX: 00000000ffffffff RCX: ffffffff81ecec6e RDX: fffffbfffffffffe RSI: 0000000000000004 RDI: ffffffffffffffea RBP: ffffffffffffffea R08: 0000000000000001 R09: ffffffffffffffed R10: fffffbfffffffffd R11: 000000000008c001 R12: 0000000000000003 R13: ffffffffffffffea R14: ffffc90003c31000 R15: 00000000ffffffea FS: 0000555555de5300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffea CR3: 0000000075191000 CR4: 00000000003526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kvm_xen_eventfd_assign arch/x86/kvm/xen.c:1720 [inline] kvm_xen_setattr_evtchn arch/x86/kvm/xen.c:1779 [inline] kvm_xen_hvm_set_attr+0x563/0x1630 arch/x86/kvm/xen.c:486 kvm_arch_vm_ioctl+0xe39/0x18b0 arch/x86/kvm/x86.c:6829 kvm_vm_ioctl+0x1661/0x2380 arch/x86/kvm/../../../virt/kvm/kvm_main.c:4816 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fe6123bdb69 Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc0dee52c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe6123bdb69 RDX: 0000000020000040 RSI: 000000004048aec9 RDI: 0000000000000004 RBP: 00007fe612381d10 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe612381da0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: CR2: ffffffffffffffea ---[ end trace 0000000000000000 ]--- RIP: 0010:arch_atomic_fetch_sub arch/x86/include/asm/atomic.h:190 [inline] RIP: 0010:atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:177 [inline] RIP: 0010:__refcount_sub_and_test include/linux/refcount.h:272 [inline] RIP: 0010:__refcount_dec_and_test include/linux/refcount.h:315 [inline] RIP: 0010:refcount_dec_and_test include/linux/refcount.h:333 [inline] RIP: 0010:kref_put include/linux/kref.h:64 [inline] RIP: 0010:eventfd_ctx_put+0x1e/0x110 fs/eventfd.c:112 Code: 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 54 55 48 89 fd 53 bb ff ff ff ff e8 cf a8 8f ff be 04 00 00 00 48 89 ef e8 f2 38 dc ff 0f c1 5d 00 bf 01 00 00 00 89 de e8 81 a5 8f ff 83 fb 01 74 35 RSP: 0018:ffffc90003c1f748 EFLAGS: 00010246 RAX: 0000000000000001 RBX: 00000000ffffffff RCX: ffffffff81ecec6e RDX: fffffbfffffffffe RSI: 0000000000000004 RDI: ffffffffffffffea RBP: ffffffffffffffea R08: 0000000000000001 R09: ffffffffffffffed R10: fffffbfffffffffd R11: 000000000008c001 R12: 0000000000000003 R13: ffffffffffffffea R14: ffffc90003c31000 R15: 00000000ffffffea FS: 0000555555de5300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffea CR3: 0000000075191000 CR4: 00000000003526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 7: 00 8: 0f 1f 40 00 nopl 0x0(%rax) c: 41 54 push %r12 e: 55 push %rbp f: 48 89 fd mov %rdi,%rbp 12: 53 push %rbx 13: bb ff ff ff ff mov $0xffffffff,%ebx 18: e8 cf a8 8f ff callq 0xff8fa8ec 1d: be 04 00 00 00 mov $0x4,%esi 22: 48 89 ef mov %rbp,%rdi 25: e8 f2 38 dc ff callq 0xffdc391c * 2a: f0 0f c1 5d 00 lock xadd %ebx,0x0(%rbp) <-- trapping instruction 2f: bf 01 00 00 00 mov $0x1,%edi 34: 89 de mov %ebx,%esi 36: e8 81 a5 8f ff callq 0xff8fa5bc 3b: 83 fb 01 cmp $0x1,%ebx 3e: 74 35 je 0x75