{"id":"CVE-2025-37807","title":"bpf: Fix kmemleak warning for percpu hashmap","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix kmemleak warning for percpu hashmap\n\nVlad Poenaru reported the following kmemleak issue:\n\n  unreferenced object 0x606fd7c44ac8 (size 32):\n    backtrace (crc 0)…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 25014e3dfa6d2fb95c920b9e6b2f0b303baa4533","Linux >= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 7758e308aeda1038aba1944f7302d34161b3effe","Linux >= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 1f1c29aa1934177349c17e3c32e68ec38a7a56df","Linux >= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 11ba7ce076e5903e7bdc1fd1498979c331b3c286","Linux 4.6"],"published":"2025-05-08","updated":"2026-10-21","sourceUpdated":"2026-10-21T12:36:29.395Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-37807","references":[{"url":"https://git.kernel.org/stable/c/25014e3dfa6d2fb95c920b9e6b2f0b303baa4533"},{"url":"https://git.kernel.org/stable/c/7758e308aeda1038aba1944f7302d34161b3effe"},{"url":"https://git.kernel.org/stable/c/1f1c29aa1934177349c17e3c32e68ec38a7a56df"},{"url":"https://git.kernel.org/stable/c/11ba7ce076e5903e7bdc1fd1498979c331b3c286"}],"tags":["cve.org"],"epss":0.00247,"epssPercentile":0.15924,"ingestedAt":"2026-10-21T12:48:53.710Z","slug":"CVE-2025-37807","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix kmemleak warning for percpu hashmap\n\nVlad Poenaru reported the following kmemleak issue:\n\n  unreferenced object 0x606fd7c44ac8 (size 32):\n    backtrace (crc 0):\n      pcpu_alloc_noprof+0x730/0xeb0\n      bpf_map_alloc_percpu+0x69/0xc0\n      prealloc_init+0x9d/0x1b0\n      htab_map_alloc+0x363/0x510\n      map_create+0x215/0x3a0\n      __sys_bpf+0x16b/0x3e0\n      __x64_sys_bpf+0x18/0x20\n      do_syscall_64+0x7b/0x150\n      entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\nFurther investigation shows the reason is due to not 8-byte aligned\nstore of percpu pointer in htab_elem_set_ptr():\n  *(void __percpu **)(l->key + key_size) = pptr;\n\nNote that the whole htab_elem alignment is 8 (for x86_64). If the key_size\nis 4, that means pptr is stored in a location which is 4 byte aligned but\nnot 8 byte aligned. In mm/kmemleak.c, scan_block() scans the memory based\non 8 byte stride, so it won't detect above pptr, hence reporting the memory\nleak.\n\nIn htab_map_alloc(), we already have\n\n        htab->elem_size = sizeof(struct htab_elem) +\n                          round_up(htab->map.key_size, 8);\n        if (percpu)\n                htab->elem_size += sizeof(void *);\n        else\n                htab->elem_size += round_up(htab->map.value_size, 8);\n\nSo storing pptr with 8-byte alignment won't cause any problem and can fix\nkmemleak too.\n\nThe issue can be reproduced with bpf selftest as well:\n  1. Enable CONFIG_DEBUG_KMEMLEAK config\n  2. Add a getchar() before skel destroy in test_hash_map() in prog_tests/for_each.c.\n     The purpose is to keep map available so kmemleak can be detected.\n  3. run './test_progs -t for_each/hash_map &' and a kmemleak should be reported.\n\n## Affected\n\n- `Linux >= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 25014e3dfa6d2fb95c920b9e6b2f0b303baa4533`\n- `Linux >= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 7758e308aeda1038aba1944f7302d34161b3effe`\n- `Linux >= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 1f1c29aa1934177349c17e3c32e68ec38a7a56df`\n- `Linux >= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 11ba7ce076e5903e7bdc1fd1498979c331b3c286`\n- `Linux 4.6`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}