Null pointer dereference in Windows DirectX allows an authorized attacker to deny service locally.
NVIDIA GPU Display Driver for Windows and Linux contains a vulnerability in the kernel mode layer, where a user in a guest VM can cause a NULL-pointer dereference in the host. A successful exploit of this vulnerability may lead to denial of service.
NVIDIA GPU Display Driver for Windows and Linux contains a vulnerability in the kernel mode layer, where a user in a guest can cause a NULL-pointer dereference in the host, which may lead to denial of service.
NVIDIA vGPU software contains a vulnerability in the Virtual GPU Manager, where a malicious user in a guest VM can cause a NULL-pointer dereference, which may lead to denial of service.
NVIDIA GPU Display Driver for Windows and Linux contains a vulnerability in the kernel mode layer, where a local user with basic capabilities can cause a null-pointer dereference, which may lead to denial of service.
NVIDIA GPU Display Driver for Windows contains a vulnerability in the kernel mode layer, where any local user can cause a null-pointer dereference, which may lead to a kernel panic.
NVIDIA GPU Display Driver for Windows and Linux contains a vulnerability in the kernel mode layer, where an unprivileged user can cause a null-pointer dereference, which may lead to denial of service.
NVIDIA GPU Driver for Windows and Linux contains a vulnerability in the kernel mode layer, where an unprivileged regular user can cause a NULL-pointer dereference, which may lead to denial of service.
Null pointer dereference in Windows DirectX allows an authorized attacker to deny service locally.
NVIDIA GPU Display Driver for Windows contains a vulnerability in the kernel mode layer (nvlddmkm.sys) handler for private IOCTLs, where an attacker with local unprivileged system access may cause a NULL pointer dereference, which may lead to denial of service in a component beyond the vulnerable component.
Race condition in some Intel(R) Aptio* V UEFI Firmware Integrator Tools may allow an authenticated user to potentially enable denial of service via local access.
In the Linux kernel, the following vulnerability has been resolved: LoongArch: Change acpi_core_pic[NR_CPUS] to acpi_core_pic[MAX_CORE_PIC] With default config, the value of NR_CPUS is 64. When HW platform has more then 64 cpus, system will crash on these platforms. MAX_CORE_PIC is the maximum cpu number in MADT table (max physical number) which can exceed the supported maximum cpu number (NR_CPUS, max logical number), but kernel should not crash. Kernel should boot cpus with NR_CPUS, let the remainder cpus stay in BIOS. The potential crash reason is that the array acpi_core_pic[NR_CPUS] can be overflowed when parsing MADT table, and it is obvious that CORE_PIC should be corresponding to physical core rather than logical core, so it is better to define the array as acpi_core_pic[MAX_CORE_PIC]. With the patch, system can boot up 64 vcpus with qemu parameter -smp 128, otherwise system will crash with the following message. [ 0.000000] CPU 0 Unable to handle kernel paging request at virtual address 0000420000004259, era == 90000000037a5f0c, ra == 90000000037a46ec [ 0.000000] Oops[#1]: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.8.0-rc2+ #192 [ 0.000000] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022 [ 0.000000] pc 90000000037a5f0c ra 90000000037a46ec tp 9000000003c90000 sp 9000000003c93d60 [ 0.000000] a0 0000000000000019 a1 9000000003d93bc0 a2 0000000000000000 a3 9000000003c93bd8 [ 0.000000] a4 9000000003c93a74 a5 9000000083c93a67 a6 9000000003c938f0 a7 0000000000000005 [ 0.000000] t0 0000420000004201 t1 0000000000000000 t2 0000000000000001 t3 0000000000000001 [ 0.000000] t4 0000000000000003 t5 0000000000000000 t6 0000000000000030 t7 0000000000000063 [ 0.000000] t8 0000000000000014 u0 ffffffffffffffff s9 0000000000000000 s0 9000000003caee98 [ 0.000000] s1 90000000041b0480 s2 9000000003c93da0 s3 9000000003c93d98 s4 9000000003c93d90 [ 0.000000] s5 9000000003caa000 s6 000000000a7fd000 s7 000000000f556b60 s8 000000000e0a4330 [ 0.000000] ra: 90000000037a46ec platform_init+0x214/0x250 [ 0.000000] ERA: 90000000037a5f0c efi_runtime_init+0x30/0x94 [ 0.000000] CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE) [ 0.000000] PRMD: 00000000 (PPLV0 -PIE -PWE) [ 0.000000] EUEN: 00000000 (-FPE -SXE -ASXE -BTE) [ 0.000000] ECFG: 00070800 (LIE=11 VS=7) [ 0.000000] ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0) [ 0.000000] BADV: 0000420000004259 [ 0.000000] PRID: 0014c010 (Loongson-64bit, Loongson-3A5000) [ 0.000000] Modules linked in: [ 0.000000] Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____)) [ 0.000000] Stack : 9000000003c93a14 9000000003800898 90000000041844f8 90000000037a46ec [ 0.000000] 000000000a7fd000 0000000008290000 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 0000000000000000 00000000019d8000 000000000f556b60 [ 0.000000] 000000000a7fd000 000000000f556b08 9000000003ca7700 9000000003800000 [ 0.000000] 9000000003c93e50 9000000003800898 9000000003800108 90000000037a484c [ 0.000000] 000000000e0a4330 000000000f556b60 000000000a7fd000 000000000f556b08 [ 0.000000] 9000000003ca7700 9000000004184000 0000000000200000 000000000e02b018 [ 0.000000] 000000000a7fd000 90000000037a0790 9000000003800108 0000000000000000 [ 0.000000] 0000000000000000 000000000e0a4330 000000000f556b60 000000000a7fd000 [ 0.000000] 000000000f556b08 000000000eaae298 000000000eaa5040 0000000000200000 [ 0.000000] ... [ 0.000000] Call Trace: [ 0.000000] [<90000000037a5f0c>] efi_runtime_init+0x30/0x94 [ 0.000000] [<90000000037a46ec>] platform_init+0x214/0x250 [ 0.000000] [<90000000037a484c>] setup_arch+0x124/0x45c [ 0.000000] [<90000000037a0790>] start_kernel+0x90/0x670 [ 0.000000] [<900000000378b0d8>] kernel_entry+0xd8/0xdc
Integer overflow in some Intel(R) Aptio* V UEFI Firmware Integrator Tools may allow an authenticated user to potentially enable denial of service via local access.
<p>A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to properly validate specific malicious data from a user on a guest operating system.</p> <p>To exploit the vulnerability, an attacker who already has a privileged account on a guest operating system, running as a virtual machine, could run a specially crafted application.</p> <p>The security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to handle these requests.</p>
<p>A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to properly validate specific malicious data from a user on a guest operating system.</p> <p>To exploit the vulnerability, an attacker who already has a privileged account on a guest operating system, running as a virtual machine, could run a specially crafted application.</p> <p>The security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to handle these requests.</p>
A flaw was found in vringh_kiov_advance in drivers/vhost/vringh.c in the host side of a virtio ring in the Linux Kernel. This issue may result in a denial of service from guest to host via zero length descriptor.
Use after free in some Intel(R) Aptio* V UEFI Firmware Integrator Tools may allowed an authenticated user to potentially enable denial of service via local access.
Untrusted pointer dereference in Storvsp.sys Driver allows an authorized attacker to deny service locally.
NVIDIA ConnectX-5, ConnectX-6, and ConnectX6-DX contain a vulnerability in the NIC firmware, where an unprivileged user can cause improper handling of exceptional conditions, which may lead to denial of service.
An issue was discovered in drivers/xen/balloon.c in the Linux kernel before 5.2.3, as used in Xen through 4.12.x, allowing guest OS users to cause a denial of service because of unrestricted resource consumption during the mapping of guest memory, aka CID-6ef36ab967c7.
Guest can force Linux netback driver to hog large amounts of kernel memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them. There are some measures taken for avoiding to pile up too much data, but those can be bypassed by the guest: There is a timeout how long the client side of an interface can stop consuming new packets before it is assumed to have stalled, but this timeout is rather long (60 seconds by default). Using a UDP connection on a fast interface can easily accumulate gigabytes of data in that time. (CVE-2021-28715) The timeout could even never trigger if the guest manages to have only one free slot in its RX queue ring page and the next package would require more than one free slot, which may be the case when using GSO, XDP, or software hashing. (CVE-2021-28714)
NVIDIA Display Driver for Windows and Linux contains a vulnerability where an attacker could leak held driver locks. A successful exploit of this vulnerability might lead to denial of service.
Windows Hyper-V Denial of Service Vulnerability
Guests can trigger NIC interface reset/abort/crash via netback It is possible for a guest to trigger a NIC interface reset/abort/crash in a Linux based network backend by sending certain kinds of packets. It appears to be an (unwritten?) assumption in the rest of the Linux network stack that packet protocol headers are all contained within the linear section of the SKB and some NICs behave badly if this is not the case. This has been reported to occur with Cisco (enic) and Broadcom NetXtrem II BCM5780 (bnx2x) though it may be an issue with other NICs/drivers as well. In case the frontend is sending requests with split headers, netback will forward those violating above mentioned assumption to the networking core, resulting in said misbehavior.
A flaw was found in the IPv4 Resource Reservation Protocol (RSVP) classifier in the Linux kernel. The xprt pointer may go beyond the linear part of the skb, leading to an out-of-bounds read in the `rsvp_classify` function. This issue may allow a local user to crash the system and cause a denial of service.
Windows Virtual Trusted Platform Module Denial of Service Vulnerability
An issue was discovered in arch/x86/kvm/vmx/nested.c in the Linux kernel before 6.2.8. nVMX on x86_64 lacks consistency checks for CR0 and CR4.
Windows Hyper-V Denial of Service Vulnerability
Privilege escalation vulnerability in DXL Broker for Windows prior to 6.0.0.280 allows local users to gain elevated privileges by exploiting weak directory controls in the logs directory. This can lead to a denial-of-service attack on the DXL Broker.
DirectX Graphics Kernel File Denial of Service Vulnerability
Windows Hyper-V Denial of Service Vulnerability
In the Linux kernel, the following vulnerability has been resolved: drm/amd/amdkfd: Fix kernel panic when reset failed and been triggered again In SRIOV configuration, the reset may failed to bring asic back to normal but stop cpsch already been called, the start_cpsch will not be called since there is no resume in this case. When reset been triggered again, driver should avoid to do uninitialization again.
In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Bury Intel PT virtualization (guest/host mode) behind CONFIG_BROKEN Hide KVM's pt_mode module param behind CONFIG_BROKEN, i.e. disable support for virtualizing Intel PT via guest/host mode unless BROKEN=y. There are myriad bugs in the implementation, some of which are fatal to the guest, and others which put the stability and health of the host at risk. For guest fatalities, the most glaring issue is that KVM fails to ensure tracing is disabled, and *stays* disabled prior to VM-Enter, which is necessary as hardware disallows loading (the guest's) RTIT_CTL if tracing is enabled (enforced via a VMX consistency check). Per the SDM: If the logical processor is operating with Intel PT enabled (if IA32_RTIT_CTL.TraceEn = 1) at the time of VM entry, the "load IA32_RTIT_CTL" VM-entry control must be 0. On the host side, KVM doesn't validate the guest CPUID configuration provided by userspace, and even worse, uses the guest configuration to decide what MSRs to save/load at VM-Enter and VM-Exit. E.g. configuring guest CPUID to enumerate more address ranges than are supported in hardware will result in KVM trying to passthrough, save, and load non-existent MSRs, which generates a variety of WARNs, ToPA ERRORs in the host, a potential deadlock, etc.
Windows Hyper-V Denial of Service Vulnerability
Windows Hyper-V Denial of Service Vulnerability
Windows Hyper-V Discrete Device Assignment (DDA) Denial of Service Vulnerability
NVIDIA Display Driver for Linux contains a vulnerability in the Multi-Instance GPU (MIG) partition management, where an insecure default initialization of memory subsystem routing resources could lead to data corruption or a hang during partition reconfiguration. A successful exploit of this vulnerability might lead to denial of service.
An issue was discovered in the Linux kernel 5.9.x through 5.11.3, as used with Xen. In some less-common configurations, an x86 PV guest OS user can crash a Dom0 or driver domain via a large amount of I/O activity. The issue relates to misuse of guest physical addresses when a configuration has CONFIG_XEN_UNPOPULATED_ALLOC but not CONFIG_XEN_BALLOON_MEMORY_HOTPLUG.
Guest can force Linux netback driver to hog large amounts of kernel memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them. There are some measures taken for avoiding to pile up too much data, but those can be bypassed by the guest: There is a timeout how long the client side of an interface can stop consuming new packets before it is assumed to have stalled, but this timeout is rather long (60 seconds by default). Using a UDP connection on a fast interface can easily accumulate gigabytes of data in that time. (CVE-2021-28715) The timeout could even never trigger if the guest manages to have only one free slot in its RX queue ring page and the next package would require more than one free slot, which may be the case when using GSO, XDP, or software hashing. (CVE-2021-28714)
The fix for XSA-365 includes initialization of pointers such that subsequent cleanup code wouldn't use uninitialized or stale values. This initialization went too far and may under certain conditions also overwrite pointers which are in need of cleaning up. The lack of cleanup would result in leaking persistent grants. The leak in turn would prevent fully cleaning up after a respective guest has died, leaving around zombie domains. All Linux versions having the fix for XSA-365 applied are vulnerable. XSA-365 was classified to affect versions back to at least 3.11.
An issue was discovered in the Linux kernel through 5.11.3, as used with Xen PV. A certain part of the netback driver lacks necessary treatment of errors such as failed memory allocations (as a result of changes to the handling of grant mapping errors). A host OS denial of service may occur during misbehavior of a networking frontend driver. NOTE: this issue exists because of an incomplete fix for CVE-2021-26931.
Windows Hyper-V Denial of Service Vulnerability
KVM in the Linux kernel on Power8 processors has a conflicting use of HSTATE_HOST_R1 to store r1 state in kvmppc_hv_entry plus in kvmppc_{save,restore}_tm, leading to a stack corruption. Because of this, an attacker with the ability run code in kernel space of a guest VM can cause the host kernel to panic. There were two commits that, according to the reporter, introduced the vulnerability: f024ee098476 ("KVM: PPC: Book3S HV: Pull out TM state save/restore into separate procedures") 87a11bb6a7f7 ("KVM: PPC: Book3S HV: Work around XER[SO] bug in fake suspend mode") The former landed in 4.8, the latter in 4.17. This was fixed without realizing the impact in 4.18 with the following three commits, though it's believed the first is the only strictly necessary commit: 6f597c6b63b6 ("KVM: PPC: Book3S PR: Add guest MSR parameter for kvmppc_save_tm()/kvmppc_restore_tm()") 7b0e827c6970 ("KVM: PPC: Book3S HV: Factor fake-suspend handling out of kvmppc_save/restore_tm") 009c872a8bc4 ("KVM: PPC: Book3S PR: Move kvmppc_save_tm/kvmppc_restore_tm to separate file")
VMware Workstation (16.x prior to 16.2.2) and Horizon Client for Windows (5.x prior to 5.5.3) contains a denial-of-service vulnerability in the Cortado ThinPrint component. The issue exists in TrueType font parser. A malicious actor with access to a virtual machine or remote desktop may exploit this issue to trigger a denial-of-service condition in the Thinprint service running on the host machine where VMware Workstation or Horizon Client for Windows is installed.
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init() l2cap_le_flowctl_init() can cause both div-by-zero and an integer overflow since hdev->le_mtu may not fall in the valid range. Move MTU from hci_dev to hci_conn to validate MTU and stop the connection process earlier if MTU is invalid. Also, add a missing validation in read_buffer_size() and make it return an error value if the validation fails. Now hci_conn_add() returns ERR_PTR() as it can fail due to the both a kzalloc failure and invalid MTU value. divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 PID: 67 Comm: kworker/u5:0 Tainted: G W 6.9.0-rc5+ #20 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: hci0 hci_rx_work RIP: 0010:l2cap_le_flowctl_init+0x19e/0x3f0 net/bluetooth/l2cap_core.c:547 Code: e8 17 17 0c 00 66 41 89 9f 84 00 00 00 bf 01 00 00 00 41 b8 02 00 00 00 4c 89 fe 4c 89 e2 89 d9 e8 27 17 0c 00 44 89 f0 31 d2 <66> f7 f3 89 c3 ff c3 4d 8d b7 88 00 00 00 4c 89 f0 48 c1 e8 03 42 RSP: 0018:ffff88810bc0f858 EFLAGS: 00010246 RAX: 00000000000002a0 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffff88810bc0f7c0 RDI: ffffc90002dcb66f RBP: ffff88810bc0f880 R08: aa69db2dda70ff01 R09: 0000ffaaaaaaaaaa R10: 0084000000ffaaaa R11: 0000000000000000 R12: ffff88810d65a084 R13: dffffc0000000000 R14: 00000000000002a0 R15: ffff88810d65a000 FS: 0000000000000000(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000100 CR3: 0000000103268003 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <TASK> l2cap_le_connect_req net/bluetooth/l2cap_core.c:4902 [inline] l2cap_le_sig_cmd net/bluetooth/l2cap_core.c:5420 [inline] l2cap_le_sig_channel net/bluetooth/l2cap_core.c:5486 [inline] l2cap_recv_frame+0xe59d/0x11710 net/bluetooth/l2cap_core.c:6809 l2cap_recv_acldata+0x544/0x10a0 net/bluetooth/l2cap_core.c:7506 hci_acldata_packet net/bluetooth/hci_core.c:3939 [inline] hci_rx_work+0x5e5/0xb20 net/bluetooth/hci_core.c:4176 process_one_work kernel/workqueue.c:3254 [inline] process_scheduled_works+0x90f/0x1530 kernel/workqueue.c:3335 worker_thread+0x926/0xe70 kernel/workqueue.c:3416 kthread+0x2e3/0x380 kernel/kthread.c:388 ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]---
arch/x86/kvm/x86.c in the Linux kernel before 4.4 does not reset the PIT counter values during state restoration, which allows guest OS users to cause a denial of service (divide-by-zero error and host OS crash) via a zero value, related to the kvm_vm_ioctl_set_pit and kvm_vm_ioctl_set_pit2 functions.
VMware Workstation and Fusion contain a heap buffer-overflow vulnerability in the Shader functionality. A malicious actor with non-administrative access to a virtual machine with 3D graphics enabled may be able to exploit this vulnerability to create a denial of service condition.
Windows Hyper-V Denial of Service Vulnerability
In the Linux kernel, the following vulnerability has been resolved: s390/bpf: Fix bpf_plt pointer arithmetic Kui-Feng Lee reported a crash on s390x triggered by the dummy_st_ops/dummy_init_ptr_arg test [1]: [<0000000000000002>] 0x2 [<00000000009d5cde>] bpf_struct_ops_test_run+0x156/0x250 [<000000000033145a>] __sys_bpf+0xa1a/0xd00 [<00000000003319dc>] __s390x_sys_bpf+0x44/0x50 [<0000000000c4382c>] __do_syscall+0x244/0x300 [<0000000000c59a40>] system_call+0x70/0x98 This is caused by GCC moving memcpy() after assignments in bpf_jit_plt(), resulting in NULL pointers being written instead of the return and the target addresses. Looking at the GCC internals, the reordering is allowed because the alias analysis thinks that the memcpy() destination and the assignments' left-hand-sides are based on different objects: new_plt and bpf_plt_ret/bpf_plt_target respectively, and therefore they cannot alias. This is in turn due to a violation of the C standard: When two pointers are subtracted, both shall point to elements of the same array object, or one past the last element of the array object ... From the C's perspective, bpf_plt_ret and bpf_plt are distinct objects and cannot be subtracted. In the practical terms, doing so confuses the GCC's alias analysis. The code was written this way in order to let the C side know a few offsets defined in the assembly. While nice, this is by no means necessary. Fix the noncompliance by hardcoding these offsets. [1] https://lore.kernel.org/bpf/c9923c1d-971d-4022-8dc8-1364e929d34c@gmail.com/
In the Linux kernel, the following vulnerability has been resolved: book3s64/radix : Align section vmemmap start address to PAGE_SIZE A vmemmap altmap is a device-provided region used to provide backing storage for struct pages. For each namespace, the altmap should belong to that same namespace. If the namespaces are created unaligned, there is a chance that the section vmemmap start address could also be unaligned. If the section vmemmap start address is unaligned, the altmap page allocated from the current namespace might be used by the previous namespace also. During the free operation, since the altmap is shared between two namespaces, the previous namespace may detect that the page does not belong to its altmap and incorrectly assume that the page is a normal page. It then attempts to free the normal page, which leads to a kernel crash. Kernel attempted to read user page (18) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x00000018 Faulting instruction address: 0xc000000000530c7c Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries CPU: 32 PID: 2104 Comm: ndctl Kdump: loaded Tainted: G W NIP: c000000000530c7c LR: c000000000530e00 CTR: 0000000000007ffe REGS: c000000015e57040 TRAP: 0300 Tainted: G W MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 84482404 CFAR: c000000000530dfc DAR: 0000000000000018 DSISR: 40000000 IRQMASK: 0 GPR00: c000000000530e00 c000000015e572e0 c000000002c5cb00 c00c000101008040 GPR04: 0000000000000000 0000000000000007 0000000000000001 000000000000001f GPR08: 0000000000000005 0000000000000000 0000000000000018 0000000000002000 GPR12: c0000000001d2fb0 c0000060de6b0080 0000000000000000 c0000060dbf90020 GPR16: c00c000101008000 0000000000000001 0000000000000000 c000000125b20f00 GPR20: 0000000000000001 0000000000000000 ffffffffffffffff c00c000101007fff GPR24: 0000000000000001 0000000000000000 0000000000000000 0000000000000000 GPR28: 0000000004040201 0000000000000001 0000000000000000 c00c000101008040 NIP [c000000000530c7c] get_pfnblock_flags_mask+0x7c/0xd0 LR [c000000000530e00] free_unref_page_prepare+0x130/0x4f0 Call Trace: free_unref_page+0x50/0x1e0 free_reserved_page+0x40/0x68 free_vmemmap_pages+0x98/0xe0 remove_pte_table+0x164/0x1e8 remove_pmd_table+0x204/0x2c8 remove_pud_table+0x1c4/0x288 remove_pagetable+0x1c8/0x310 vmemmap_free+0x24/0x50 section_deactivate+0x28c/0x2a0 __remove_pages+0x84/0x110 arch_remove_memory+0x38/0x60 memunmap_pages+0x18c/0x3d0 devm_action_release+0x30/0x50 release_nodes+0x68/0x140 devres_release_group+0x100/0x190 dax_pmem_compat_release+0x44/0x80 [dax_pmem_compat] device_for_each_child+0x8c/0x100 [dax_pmem_compat_remove+0x2c/0x50 [dax_pmem_compat] nvdimm_bus_remove+0x78/0x140 [libnvdimm] device_remove+0x70/0xd0 Another issue is that if there is no altmap, a PMD-sized vmemmap page will be allocated from RAM, regardless of the alignment of the section start address. If the section start address is not aligned to the PMD size, a VM_BUG_ON will be triggered when setting the PMD-sized page to page table. In this patch, we are aligning the section vmemmap start address to PAGE_SIZE. After alignment, the start address will not be part of the current namespace, and a normal page will be allocated for the vmemmap mapping of the current section. For the remaining sections, altmaps will be allocated. During the free operation, the normal page will be correctly freed. In the same way, a PMD_SIZE vmemmap page will be allocated only if the section start address is PMD_SIZE-aligned; otherwise, it will fall back to a PAGE-sized vmemmap allocation. Without this patch ================== NS1 start NS2 start _________________________________________________________ | NS1 | NS2 | --------------------------------------------------------- | Altmap| Altmap | .....|Altmap| Altmap | ........... | NS1 | NS1 ---truncated---