{"id":"CVE-2021-47462","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/mempolicy: do not allow illegal MPOL_F_NUMA_BALANCING | MPOL_LOCAL in mbind()\n\nsyzbot reported access to unitialized memory in mbind() [1]\n\nIssue came with commit bda420b98505 (\"numa balancing: migrate on fault\namong multiple bound nodes\")\n\nThis commit added a new bit in MPOL_MODE_FLAGS, but only checked valid\ncombination (MPOL_F_NUMA_BALANCING can only be used with MPOL_BIND) in\ndo_set_mempolicy()\n\nThis patch moves the check in sanitize_mpol_flags() so that it is also\nused by mbind()\n\n  [1]\n  BUG: KMSAN: uninit-value in __mpol_equal+0x567/0x590 mm/mempolicy.c:2260\n   __mpol_equal+0x567/0x590 mm/mempolicy.c:2260\n   mpol_equal include/linux/mempolicy.h:105 [inline]\n   vma_merge+0x4a1/0x1e60 mm/mmap.c:1190\n   mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811\n   do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333\n   kernel_mbind mm/mempolicy.c:1483 [inline]\n   __do_sys_mbind mm/mempolicy.c:1490 [inline]\n   __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486\n   __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486\n   do_syscall_x64 arch/x86/entry/common.c:51 [inline]\n   do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82\n   entry_SYSCALL_64_after_hwframe+0x44/0xae\n\n  Uninit was created at:\n   slab_alloc_node mm/slub.c:3221 [inline]\n   slab_alloc mm/slub.c:3230 [inline]\n   kmem_cache_alloc+0x751/0xff0 mm/slub.c:3235\n   mpol_new mm/mempolicy.c:293 [inline]\n   do_mbind+0x912/0x15f0 mm/mempolicy.c:1289\n   kernel_mbind mm/mempolicy.c:1483 [inline]\n   __do_sys_mbind mm/mempolicy.c:1490 [inline]\n   __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486\n   __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486\n   do_syscall_x64 arch/x86/entry/common.c:51 [inline]\n   do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82\n   entry_SYSCALL_64_after_hwframe+0x44/0xae\n  =====================================================\n  Kernel panic - not syncing: panic_on_kmsan set ...\n  CPU: 0 PID: 15049 Comm: syz-executor.0 Tainted: G    B             5.15.0-rc2-syzkaller #0\n  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\n  Call Trace:\n   __dump_stack lib/dump_stack.c:88 [inline]\n   dump_stack_lvl+0x1ff/0x28e lib/dump_stack.c:106\n   dump_stack+0x25/0x28 lib/dump_stack.c:113\n   panic+0x44f/0xdeb kernel/panic.c:232\n   kmsan_report+0x2ee/0x300 mm/kmsan/report.c:186\n   __msan_warning+0xd7/0x150 mm/kmsan/instrumentation.c:208\n   __mpol_equal+0x567/0x590 mm/mempolicy.c:2260\n   mpol_equal include/linux/mempolicy.h:105 [inline]\n   vma_merge+0x4a1/0x1e60 mm/mmap.c:1190\n   mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811\n   do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333\n   kernel_mbind mm/mempolicy.c:1483 [inline]\n   __do_sys_mbind mm/mempolicy.c:1490 [inline]\n   __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486\n   __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486\n   do_syscall_x64 arch/x86/entry/common.c:51 [inline]\n   do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82\n   entry_SYSCALL_64_after_hwframe+0x44/0xae","modified":"2026-03-14T11:19:11.475353Z","published":"2024-05-22T07:15:11.117Z","related":["SUSE-SU-2024:2008-1","SUSE-SU-2024:2011-1","SUSE-SU-2024:2019-1","SUSE-SU-2024:2189-1","SUSE-SU-2024:2190-1"],"references":[{"type":"FIX","url":"https://git.kernel.org/stable/c/6d2aec9e123bb9c49cb5c7fc654f25f81e688e8c"},{"type":"FIX","url":"https://git.kernel.org/stable/c/9ee4e9ae98f1f262d6fae0d266cfdf3ba2c321d9"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47462.json","unresolved_ranges":[{"events":[{"introduced":"5.12"},{"fixed":"5.14.15"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc1"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc2"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc3"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc4"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc5"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc6"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}