CVE-2026-46029

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mm/slab: return NULL early from kmalloc_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, kmalloc_nolock() called from NMI context can re-enter the slab<br /> allocator and acquire n-&gt;list_lock that the interrupted context is<br /> already holding, corrupting slab state.<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 /> get_from_partial_node+0x120/0x4d0<br /> ___slab_alloc+0x8a/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.