{"id":"CVE-2026-68090","summary":"debugobjects: Plug race against a concurrent OOM disable","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndebugobjects: Plug race against a concurrent OOM disable\n\nsyzbot reported a puzzling splat:\n\n   WARNING: kernel/time/hrtimer.c:443 at stub_timer+0xa/0x20\n\nstub_timer() is installed as timer callback function in\nhrtimer_fixup_assert_init(), which is invoked when\ndebug_object_assert_init() can't find a shadow object. In that case debug\nobjects emits a warning about it before invoking the fixup.\n\nThough the provided console log lacks this warning and instead has the\nfollowing a few seconds before the splat:\n\n     ODEBUG: Out of memory. ODEBUG disabled\n\nSo the object was looked up in debug_object_assert_init() and the lookup\nfailed due a concurrent out of memory situation which disabled debug\nobjects and freed the shadow objects:\n\ndebug_object_assert_init()\n        if (!debug_objects_enabled)\n        \treturn;                         obj = alloc();\n                \t\t\t\tif (!obj) {\n\t\t\t\t\t\t\t// Out of memory\n                                                \tdebug_objects_enabled = false;\n                                                        free_objects();\n        obj = lookup_or_alloc();\n\n        // The lookup failed because the other side\n        // removed the objects, so this returns\n        // an error code as the object in question\n        // is not statically initialized\n\n\tif (!IS_ERR_OR_NULL(obj))\n        \treturn;\n        if (!obj) {\n        \tdebug_oom();\n                return;\n        }\n\n        print(...)\n           if (!debug_objects_enabled)\n                return;\n\n        fixup(...)\n\nThe debug object splat is skipped because debug_objects_enabled is false,\nbut the fixup callback is invoked unconditionally, which makes the timer\ndisfunctional.\n\nThis is only a problem in debug_object_assert_init() and\ndebug_object_activate() as both have to handle statically initialized\nobjects and therefore must handle the error pointer return case\ngracefully. All other places only handle the found/not found case and the\nNULL pointer return is a signal for OOM. Otherwise they get a valid shadow\nobject.\n\nPlug the hole by checking whether debug objects are still enabled before\ninvoking the print and fixup function in those two places.","modified":"2026-08-12T04:18:45.412362858Z","published":"2026-08-10T11:51:45.149Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68090.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1f4f02b336c3be125c8fcf87df73db2e0e028b8b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/203a965bf2ab43130778d8214fb0c3c8c2d19cdf"},{"type":"WEB","url":"https://git.kernel.org/stable/c/23da32e88627e63e0864f59f4c63a2dc0ab851a3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2d5e320b7ab9b25229ac4331541964a58b5e1d29"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b81dde13cc163450dcb402dcc915ef13ba241e01"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c00164c9e7fa6145886ad666806cb5347895de5c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d663fbf28b2eebe665bb9cf828d7d528e5a8707e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e2e255d07723c330dded8e576ce28a8d23a692ce"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68090.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68090"},{"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":"b84d435cc228e87951f3bbabf6cc4a5f25d5fb16"},{"fixed":"2d5e320b7ab9b25229ac4331541964a58b5e1d29"},{"fixed":"203a965bf2ab43130778d8214fb0c3c8c2d19cdf"},{"fixed":"23da32e88627e63e0864f59f4c63a2dc0ab851a3"},{"fixed":"d663fbf28b2eebe665bb9cf828d7d528e5a8707e"},{"fixed":"e2e255d07723c330dded8e576ce28a8d23a692ce"},{"fixed":"c00164c9e7fa6145886ad666806cb5347895de5c"},{"fixed":"1f4f02b336c3be125c8fcf87df73db2e0e028b8b"},{"fixed":"b81dde13cc163450dcb402dcc915ef13ba241e01"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-68090.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.3.0"},{"fixed":"5.10.261"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.212"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.178"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.145"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.96"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.39"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-68090.json"}}],"schema_version":"1.9.0"}