Riskcovery

CVE-2026-46029

mm/slab: return NULL early from kmalloc_nolock() in NMI on UP

State
Published
Severity
7.0 High
Published
May 27, 2026
Updated
Aug 5, 2026
Reserved
May 13, 2026

Read the record on cve.org

Description

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

mm/slab: return NULL early from kmalloc_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, kmalloc_nolock() called from NMI context can re-enter the slab allocator and acquire n->list_lock that the interrupted context is already holding, corrupting slab state.

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 get_from_partial_node+0x120/0x4d0 ___slab_alloc+0x8a/0x4c0 kmalloc_nolock_noprof+0x164/0x310 [...] </NMI>

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

Scores

CVSSScoreVectorSource
3.17.0 HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HLinux

Weaknesses

The record names no weakness.

Affected Products

ProductVersions
LinuxLinux
  • af92793e52c3a99b828ed4bdd277fd3e11c18d08 to before a8d95d274be241ad21f6523bf2d6ba0d7d7e46b7Affected
  • af92793e52c3a99b828ed4bdd277fd3e11c18d08 to before d66553204a15bdb257d9ef8aca1e12f5fbb910b2Affected
  • af92793e52c3a99b828ed4bdd277fd3e11c18d08 to before 5b31044e649e3e54c2caef135c09b371c2fbcd08Affected
LinuxLinux
  • 6.18Affected
  • before 6.18Not affected
  • 6.18.27 through 6.18.*Not affected
  • 7.0.4 through 7.0.*Not affected
  • 7.1 and laterNot affected

References

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