CVE-2026-46035

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP<br /> <br /> On UP kernels (!CONFIG_SMP), spin_trylock() is a no-op that<br /> unconditionally succeeds even when the lock is already held. As a<br /> result, alloc_frozen_pages_nolock() called from NMI context can<br /> re-enter rmqueue() and acquire the zone lock that the interrupted<br /> context is already holding, corrupting the freelists.<br /> <br /> With CONFIG_DEBUG_SPINLOCK on UP, the following BUG is triggered with<br /> the slub_kunit test module:<br /> <br /> BUG: spinlock trylock failure on UP on CPU#0, kunit_try_catch/243<br /> [...]<br /> Call Trace:<br /> <br /> dump_stack_lvl+0x3f/0x60<br /> do_raw_spin_trylock+0x41/0x50<br /> _raw_spin_trylock+0x24/0x50<br /> rmqueue.isra.0+0x2a9/0xa70<br /> get_page_from_freelist+0xeb/0x450<br /> alloc_frozen_pages_nolock_noprof+0x111/0x1e0<br /> allocate_slab+0x42a/0x500<br /> ___slab_alloc+0xa7/0x4c0<br /> kmalloc_nolock_noprof+0x164/0x310<br /> [...]<br /> <br /> <br /> Fix this by returning NULL early when invoked from NMI on a UP kernel.