{"id":"CVE-2022-49648","summary":"tracing/histograms: Fix memory leak problem","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/histograms: Fix memory leak problem\n\nThis reverts commit 46bbe5c671e06f070428b9be142cc4ee5cedebac.\n\nAs commit 46bbe5c671e0 (\"tracing: fix double free\") said, the\n\"double free\" problem reported by clang static analyzer is:\n  \u003e In parse_var_defs() if there is a problem allocating\n  \u003e var_defs.expr, the earlier var_defs.name is freed.\n  \u003e This free is duplicated by free_var_defs() which frees\n  \u003e the rest of the list.\n\nHowever, if there is a problem allocating N-th var_defs.expr:\n  + in parse_var_defs(), the freed 'earlier var_defs.name' is\n    actually the N-th var_defs.name;\n  + then in free_var_defs(), the names from 0th to (N-1)-th are freed;\n\n                        IF ALLOCATING PROBLEM HAPPENED HERE!!! -+\n                                                                 \\\n                                                                  |\n          0th           1th                 (N-1)-th      N-th    V\n          +-------------+-------------+-----+-------------+-----------\nvar_defs: | name | expr | name | expr | ... | name | expr | name | ///\n          +-------------+-------------+-----+-------------+-----------\n\nThese two frees don't act on same name, so there was no \"double free\"\nproblem before. Conversely, after that commit, we get a \"memory leak\"\nproblem because the above \"N-th var_defs.name\" is not freed.\n\nIf enable CONFIG_DEBUG_KMEMLEAK and inject a fault at where the N-th\nvar_defs.expr allocated, then execute on shell like:\n  $ echo 'hist:key=call_site:val=$v1,$v2:v1=bytes_req,v2=bytes_alloc' \u003e \\\n/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger\n\nThen kmemleak reports:\n  unreferenced object 0xffff8fb100ef3518 (size 8):\n    comm \"bash\", pid 196, jiffies 4295681690 (age 28.538s)\n    hex dump (first 8 bytes):\n      76 31 00 00 b1 8f ff ff                          v1......\n    backtrace:\n      [\u003c0000000038fe4895\u003e] kstrdup+0x2d/0x60\n      [\u003c00000000c99c049a\u003e] event_hist_trigger_parse+0x206f/0x20e0\n      [\u003c00000000ae70d2cc\u003e] trigger_process_regex+0xc0/0x110\n      [\u003c0000000066737a4c\u003e] event_trigger_write+0x75/0xd0\n      [\u003c000000007341e40c\u003e] vfs_write+0xbb/0x2a0\n      [\u003c0000000087fde4c2\u003e] ksys_write+0x59/0xd0\n      [\u003c00000000581e9cdf\u003e] do_syscall_64+0x3a/0x80\n      [\u003c00000000cf3b065c\u003e] entry_SYSCALL_64_after_hwframe+0x46/0xb0","modified":"2026-04-02T08:27:47.400642Z","published":"2025-02-26T02:23:52.035Z","related":["ALSA-2025:20518","SUSE-SU-2025:1027-1","SUSE-SU-2025:1176-1","SUSE-SU-2025:1183-1","SUSE-SU-2025:1194-1","SUSE-SU-2025:1241-1","SUSE-SU-2025:1263-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49648.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/22eeff55679d9e7c0f768c79bfbd83e2f8142d89"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4d453eb5e1eec89971aa5b3262857ee26cfdffd3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/78a1400c42ee11197eb1f0f85ba51df9a4fdfff0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7edc3945bdce9c39198a10d6129377a5c53559c2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/eb622d5580b9e2ff694f62da6410618bd73853cb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ecc6dec12c33aa92c086cd702af9f544ddaf3c75"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49648.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-49648"},{"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":"240dd5118a9e0454f280ffeae63f22bd14735733"},{"fixed":"eb622d5580b9e2ff694f62da6410618bd73853cb"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"e92c490f104993cea35e5f5d5108ac12df1850ac"},{"fixed":"ecc6dec12c33aa92c086cd702af9f544ddaf3c75"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"46bbe5c671e06f070428b9be142cc4ee5cedebac"},{"fixed":"78a1400c42ee11197eb1f0f85ba51df9a4fdfff0"},{"fixed":"22eeff55679d9e7c0f768c79bfbd83e2f8142d89"},{"fixed":"4d453eb5e1eec89971aa5b3262857ee26cfdffd3"},{"fixed":"7edc3945bdce9c39198a10d6129377a5c53559c2"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"e3a23511638a3dcf0275c1e71a46d1ca2e2e6788"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-49648.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"}]}