{"id":"CVE-2026-93253","revision":null,"records":[{"revision":"b2a35ea5a3c3476eb94101ac9ef6ee69","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-93253","aliases":[],"title":"sched/isolation: Defer freeing of cpumask memblock memory to initcall","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/isolation: Defer freeing of cpumask memblock memory to initcall\n\nWhen testing a linux-next kernel with commit 59bd1d914bb5 (\"memblock:\nwarn when freeing reserved memory before memory map is initialized\"),\nthe following warning was hit when there was a \"nohz_full\" kernel boot\nparameter.\n\n Cannot free reserved memory because of deferred initialization of the memory map\n WARNING: mm/memblock.c:904 at __free_reserved_area+0xde/0xf0, CPU#0: swapper/0/0\n :\n Call Trace:\n \n memblock_phys_free+0xcb/0x100\n housekeeping_init+0x14c/0x170\n start_kernel+0x207/0x450\n x86_64_start_reservations+0x24/0x30\n x86_64_start_kernel+0xda/0xe0\n common_startup_64+0x13e/0x141\n \n\nIOW, we shouldn't free memblock allocated memory so early\nin the boot process when memory map isn't fully initialized in\ndeferred_init_memmap().\n\nFix it by saving the housekeeping cpumask memblock memory to be\nfreed into a llist free list in housekeeping_init() and add a new\nhousekeeping_late_init() helper to defer the actual freeing of memblock\nmemory to when initcall's are being processed. The cpumask memblock\nmemory is treated as a llist_node with the size of a \"long\" type which\nis also smallest cpumask size that can be allocated.\n\nThe non-atomic version of the llist APIs are used as there is no\ncontention.\n\nThis commit depends on the presence of commit 7c2eee9c1367 (\"memblock:\ndon't touch memblock arrays when memblock_free() is called late\")\nto prevent a KASAN UAF bug report [1].\n\n [1] https://lore.kernel.org/lkml/20260505051821.1107133-1-longman@redhat.com/","state":0,"publishedAt":"2026-09-24T15:51:29.259+00:00","modifiedAt":"2026-10-19T09:08:06.84+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"kernel/sched/isolation.c\"\n ],\n \"versions\": [\n {\n \"version\": \"27c3a5967f054ab666704cb28f2aeb18ca07cab7\",\n \"lessThan\": \"811fdac2d1bdf0b0d3fda262aac288ddd13a1422\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"27c3a5967f054ab666704cb28f2aeb18ca07cab7\",\n \"lessThan\": \"2b58c749b8c5244e259a0230bc57b10b010dc545\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"kernel/sched/isolation.c\"\n ],\n \"versions\": [\n {\n \"version\": \"7.0\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"7.0\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.6\",\n \"lessThanOrEqual\": \"7.2.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.3\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/811fdac2d1bdf0b0d3fda262aac288ddd13a1422","https://git.kernel.org/stable/c/2b58c749b8c5244e259a0230bc57b10b010dc545"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-93253","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-93253","identifiers":["CVE-2026-93253"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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