{"id":"CVE-2025-37807","state":"PUBLISHED","title":"bpf: Fix kmemleak warning for percpu hashmap","description":"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):\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.","publishedAt":"2025-05-08T06:26:06.296Z","updatedAt":"2026-10-30T12:21:21.057Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"c5f4b04e1838b9eec426d80500af49cff8631762","versionType":"git"},{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"25014e3dfa6d2fb95c920b9e6b2f0b303baa4533","versionType":"git"},{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"7758e308aeda1038aba1944f7302d34161b3effe","versionType":"git"},{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"1f1c29aa1934177349c17e3c32e68ec38a7a56df","versionType":"git"},{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"11ba7ce076e5903e7bdc1fd1498979c331b3c286","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/hashtab.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.6","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.26","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.14.5","status":"unaffected","lessThanOrEqual":"6.14.*","versionType":"semver"},{"version":"6.15","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/hashtab.c"]}],"references":["https://git.kernel.org/stable/c/c5f4b04e1838b9eec426d80500af49cff8631762","https://git.kernel.org/stable/c/25014e3dfa6d2fb95c920b9e6b2f0b303baa4533","https://git.kernel.org/stable/c/7758e308aeda1038aba1944f7302d34161b3effe","https://git.kernel.org/stable/c/1f1c29aa1934177349c17e3c32e68ec38a7a56df","https://git.kernel.org/stable/c/11ba7ce076e5903e7bdc1fd1498979c331b3c286"],"weaknesses":[],"ingestedAt":"2026-10-30T12:38:04.623Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/37xxx/CVE-2025-37807.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-37807","state":"PUBLISHED","datePublished":"2025-05-08T06:26:06.296Z","dateUpdated":"2026-10-30T12:21:21.057Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T04:51:23.942Z"},"containers":{"cna":{"title":"bpf: Fix kmemleak warning for percpu hashmap","descriptions":[{"lang":"en","value":"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):\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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"c5f4b04e1838b9eec426d80500af49cff8631762","versionType":"git"},{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"25014e3dfa6d2fb95c920b9e6b2f0b303baa4533","versionType":"git"},{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"7758e308aeda1038aba1944f7302d34161b3effe","versionType":"git"},{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"1f1c29aa1934177349c17e3c32e68ec38a7a56df","versionType":"git"},{"version":"824bd0ce6c7c43a9e1e210abf124958e54d88342","status":"affected","lessThan":"11ba7ce076e5903e7bdc1fd1498979c331b3c286","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/hashtab.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.6","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.26","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.14.5","status":"unaffected","lessThanOrEqual":"6.14.*","versionType":"semver"},{"version":"6.15","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/hashtab.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c5f4b04e1838b9eec426d80500af49cff8631762"},{"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:21:21.057Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.12.26"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.14.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.15"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}