{"id":"CVE-2026-46029","summary":"mm/slab: return NULL early from kmalloc_nolock() in NMI on UP","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slab: return NULL early from kmalloc_nolock() in NMI on UP\n\nOn UP kernels (!CONFIG_SMP), spin_trylock() is a no-op that\nunconditionally succeeds even when the lock is already held. As a\nresult, kmalloc_nolock() called from NMI context can re-enter the slab\nallocator and acquire n-\u003elist_lock that the interrupted context is\nalready holding, corrupting slab state.\n\nWith CONFIG_DEBUG_SPINLOCK on UP, the following BUG is triggered with\nthe slub_kunit test module:\n\n  BUG: spinlock trylock failure on UP on CPU#0, kunit_try_catch/243\n  [...]\n  Call Trace:\n   \u003cNMI\u003e\n   dump_stack_lvl+0x3f/0x60\n   do_raw_spin_trylock+0x41/0x50\n   _raw_spin_trylock+0x24/0x50\n   get_from_partial_node+0x120/0x4d0\n   ___slab_alloc+0x8a/0x4c0\n   kmalloc_nolock_noprof+0x164/0x310\n   [...]\n   \u003c/NMI\u003e\n\nFix this by returning NULL early when invoked from NMI on a UP kernel.","modified":"2026-06-18T03:56:52.433920341Z","published":"2026-05-27T12:56:38.376Z","related":["openSUSE-SU-2026:10954-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46029.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5b31044e649e3e54c2caef135c09b371c2fbcd08"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a8d95d274be241ad21f6523bf2d6ba0d7d7e46b7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d66553204a15bdb257d9ef8aca1e12f5fbb910b2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46029.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46029"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"af92793e52c3a99b828ed4bdd277fd3e11c18d08"},{"fixed":"a8d95d274be241ad21f6523bf2d6ba0d7d7e46b7"},{"fixed":"d66553204a15bdb257d9ef8aca1e12f5fbb910b2"},{"fixed":"5b31044e649e3e54c2caef135c09b371c2fbcd08"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-46029.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.18.0"},{"fixed":"6.18.27"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-46029.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}