{"id":"CVE-2025-21933","summary":"arm: pgtable: fix NULL pointer dereference issue","details":"In the Linux kernel, the following vulnerability has been resolved:\n\narm: pgtable: fix NULL pointer dereference issue\n\nWhen update_mmu_cache_range() is called by update_mmu_cache(), the vmf\nparameter is NULL, which will cause a NULL pointer dereference issue in\nadjust_pte():\n\nUnable to handle kernel NULL pointer dereference at virtual address 00000030 when read\nHardware name: Atmel AT91SAM9\nPC is at update_mmu_cache_range+0x1e0/0x278\nLR is at pte_offset_map_rw_nolock+0x18/0x2c\nCall trace:\n update_mmu_cache_range from remove_migration_pte+0x29c/0x2ec\n remove_migration_pte from rmap_walk_file+0xcc/0x130\n rmap_walk_file from remove_migration_ptes+0x90/0xa4\n remove_migration_ptes from migrate_pages_batch+0x6d4/0x858\n migrate_pages_batch from migrate_pages+0x188/0x488\n migrate_pages from compact_zone+0x56c/0x954\n compact_zone from compact_node+0x90/0xf0\n compact_node from kcompactd+0x1d4/0x204\n kcompactd from kthread+0x120/0x12c\n kthread from ret_from_fork+0x14/0x38\nException stack(0xc0d8bfb0 to 0xc0d8bff8)\n\nTo fix it, do not rely on whether 'ptl' is equal to decide whether to hold\nthe pte lock, but decide it by whether CONFIG_SPLIT_PTE_PTLOCKS is\nenabled.  In addition, if two vmas map to the same PTE page, there is no\nneed to hold the pte lock again, otherwise a deadlock will occur.  Just\nadd the need_lock parameter to let adjust_pte() know this information.","modified":"2026-04-02T12:45:17.393159Z","published":"2025-04-01T15:41:02.300Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21933.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/91d011efe30aedde067ce6d218d521cf99b162e5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a564ccfe300fa6a065beda06ab7f3c140d6b4d63"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21933.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-21933"},{"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":"fc9c45b71f43cafcc0435dd4c7a2d3b99955a0fa"},{"fixed":"91d011efe30aedde067ce6d218d521cf99b162e5"},{"fixed":"a564ccfe300fa6a065beda06ab7f3c140d6b4d63"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21933.json"}}],"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"}]}