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.
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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
|
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Fixes
Solution
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Workaround
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References
History
Wed, 27 May 2026 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | mm/slab: return NULL early from kmalloc_nolock() in NMI on UP | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-27T12:56:38.376Z
Reserved: 2026-05-13T15:03:33.093Z
Link: CVE-2026-46029
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2026-05-27T14:17:21.563
Modified: 2026-05-27T14:48:03.013
Link: CVE-2026-46029
Redhat
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OpenCVE Enrichment
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Weaknesses
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