CVE-2026-46035 — mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP

On UP kernels (!CONFIG_SMP), spin_trylock() is a no-op that unconditionally succeeds even when the lock is already held. As a result, alloc_frozen_pages_nolock() called from NMI context can re-enter rmqueue() and acquire the zone lock that the interrupted context is already holding, corrupting the freelists.

With CONFIG_DEBUG_SPINLOCK on UP, the following BUG is triggered with the slub_kunit test module:

BUG: spinlock trylock failure on UP on CPU#0, kunit_try_catch/243 [...] Call Trace: <NMI> dump_stack_lvl+0x3f/0x60 do_raw_spin_trylock+0x41/0x50 _raw_spin_trylock+0x24/0x50 rmqueue.isra.0+0x2a9/0xa70 get_page_from_freelist+0xeb/0x450 alloc_frozen_pages_nolock_noprof+0x111/0x1e0 allocate_slab+0x42a/0x500 ___slab_alloc+0xa7/0x4c0 kmalloc_nolock_noprof+0x164/0x310 [...] </NMI>

Fix this by returning NULL early when invoked from NMI on a UP kernel.

USN-8488-1 — linux, linux-aws, linux-gcp, linux-ibm, linux-oracle, linux-realtime vulnerabilities

Affected: Ubuntu:26.04:LTS: linux, Ubuntu:26.04:LTS: linux-aws, Ubuntu:26.04:LTS: linux-gcp, Ubuntu:26.04:LTS: linux-ibm, Ubuntu:26.04:LTS: linux-oracle, Ubuntu:26.04:LTS: linux-realtime

It was discovered that some AMD processors did not properly clear data in the floating point divider unit during speculative execution. A local attacker could use this to expose sensitive information. (CVE-2025-54505)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM64 architecture; - x86 architecture; - Block layer subsystem; - Cryptographic API; - Rados block device (RBD) driver; - Compressed RAM block device driver; - Character device driver; - TPM device driver; - Hardware crypto device drivers; - EDAC drivers; - GPU drivers; - Greybus drivers; - HID subsystem; - Microsoft Hyper-V drivers; - Hardware monitoring drivers; - I2C subsystem; - IIO subsystem; - InfiniBand drivers; - Input Device core drivers; - LED subsystem; - Multiple devices driver; - Media drivers; - IBM Advanced System Management driver; - MTD block device drivers; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - NTB driver; - NVME drivers; - Device tree and open firmware driver; - PCI subsystem; - Remote Processor subsystem; - SCSI subsystem; - SPI subsystem; - Realtek RTL8723BS SDIO drivers; - SM750 framebuffer staging driver; - Thermal drivers; - USB Gadget drivers; - USB over IP driver; - VFIO drivers; - Framebuffer layer; - 9P distributed file system; - AFS file…

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CVE-2026-46035 — mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP

USN-8488-1 — linux, linux-aws, linux-gcp, linux-ibm, linux-oracle, linux-realtime vulnerabilities