{"id":"CVE-2026-74636","summary":"tracing: Fix race between update_event_fields and, event_define_fields","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix race between update_event_fields and, event_define_fields\n\nThe following sequence may leads race between event_define_fields()\nand update_event_fields():\n\n CPU0 (loads module A)                      CPU1 (loads module B)\n ===============================            ===============================\n load_module(A)                             load_module(B)\n   notifier_call_chain                        notifier_call_chain\n     trace_module_notify                        trace_module_notify\n       mutex_lock(&event_mutex)                   trace_event_update_all()\n         trace_module_add_events(A)                 down_write(&trace_event_sem)\n            __register_event(call_A)\n              __add_event_to_tracers(call_A)\n                event_define_fields(call_A)\n                  for each f:                         list_for_each_entry(field,\n                    list_add(&f-\u003elink,                                    &class-\u003efields, link)\n                             &class-\u003efields)            field = class-\u003efields-\u003enext;\n\nWhere access to the class-\u003efields is not protected by the event_mutex in\ntrace_event_update_all().\n\nThis produces the following panic:\n   Unable to handle kernel access ... at virtual address 0000000000000018\n   pc : update_event_fields+0xf8/0x368\n   Call trace:\n    update_event_fields+0xf8/0x368\n    trace_event_update_all+0x7c/0x2b4\n    trace_module_notify+0x4c/0x1dc\n    notifier_call_chain+0x84/0x168\n    blocking_notifier_call_chain_robust+0x64/0xd4\n    load_module+0x10c8/0x123c\n    __arm64_sys_finit_module+0x230/0x31c\n\nFix by taking event_mutex in trace_event_update_all() before\ntrace_event_sem.","modified":"2026-10-28T02:31:00.095674436Z","published":"2026-08-22T15:32:16.026Z","related":["SUSE-SU-2026:24179-1","SUSE-SU-2026:24181-1","SUSE-SU-2026:24182-1","SUSE-SU-2026:24184-1","SUSE-SU-2026:24197-1","SUSE-SU-2026:24235-1","SUSE-SU-2026:24315-1","SUSE-SU-2026:24316-1","SUSE-SU-2026:4640-1","SUSE-SU-2026:4706-1","openSUSE-SU-2026:22091-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74636.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4e39f7b4d9d36508c53e89e6cbc640728df870b5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a30d421468300b1e7b2f233136aeb2db8013f555"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c3730b8373bb5059d735509b9e6a00d7eb337d7c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e5f1d301b4bdaa4206db251fdc691f623162b0a8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ed49684e69f846bf50b5050651ccdb87cfd152c0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f128740f39ab28d1f4ad5bdd10f3e117eec0c374"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fdeb190b0905a6aaed1e5d6adfb8613214748d7d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74636.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74636"},{"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":"7c6bd60999f32138e3b73fd97ea11ef47a94de25"},{"fixed":"4e39f7b4d9d36508c53e89e6cbc640728df870b5"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"b3bc8547d3be60898818885f5bf22d0a62e2eb48"},{"fixed":"a30d421468300b1e7b2f233136aeb2db8013f555"},{"fixed":"e5f1d301b4bdaa4206db251fdc691f623162b0a8"},{"fixed":"fdeb190b0905a6aaed1e5d6adfb8613214748d7d"},{"fixed":"ed49684e69f846bf50b5050651ccdb87cfd152c0"},{"fixed":"f128740f39ab28d1f4ad5bdd10f3e117eec0c374"},{"fixed":"c3730b8373bb5059d735509b9e6a00d7eb337d7c"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.15.33"},{"fixed":"5.15.216"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.16.19"},{"fixed":"5.17"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.17.2"},{"fixed":"5.18"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"55defdf935fab9f2989a197aae1042c082d9a343"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0c53a5c80e6e286733381a1d9f255ba4039e2e45"}]}],"versions":["v5.15.215","v5.15.214","v5.15.213","v5.15.212","v5.15.211","v5.15.210","v5.15.209","v5.15.208","v5.15.207","v5.15.206","v5.15.205","v5.15.204","v5.15.203","v5.15.202","v5.15.201","v5.15.200","v5.15.199","v5.15.198","v5.15.197","v5.15.196","v5.15.195","v5.15.194","v5.15.193","v5.15.192","v5.15.191","v5.15.190","v5.15.189","v5.15.188","v5.15.187","v5.15.186","v5.15.185","v5.15.184","v5.15.183","v5.15.182","v5.15.181","v5.15.180","v5.15.179","v5.15.178","v5.15.177","v5.15.176","v5.15.175","v5.15.174","v5.15.173","v5.15.172","v5.15.171","v5.15.170","v5.15.169","v5.15.168","v5.15.167","v5.15.166","v5.15.165","v5.15.164","v5.15.163","v5.15.162","v5.15.161","v5.15.160","v5.15.159","v5.15.158","v5.15.157","v5.15.156","v5.15.155","v5.15.154","v5.15.153","v5.15.152","v5.15.151","v5.15.150","v5.15.149","v5.15.148","v5.15.147","v5.15.146","v5.15.145","v5.15.144","v5.15.143","v5.15.142","v5.15.141","v5.15.140","v5.15.139","v5.15.138","v5.15.137","v5.15.136","v5.15.135","v5.15.134","v5.15.133","v5.15.132","v5.15.131","v5.15.130","v5.15.129","v5.15.128","v5.15.127","v5.15.126","v5.15.125","v5.15.124","v5.15.123","v5.15.122","v5.15.121","v5.15.120","v5.15.119","v5.15.118","v5.15.117","v5.15.116","v5.15.115","v5.15.114","v5.15.113","v5.15.112","v5.15.111","v5.15.110","v5.15.109","v5.15.108","v5.15.107","v5.15.106","v5.15.105","v5.15.104","v5.15.103","v5.15.102","v5.15.101","v5.15.100","v5.15.99","v5.15.98","v5.15.97","v5.15.96","v5.15.95","v5.15.94","v5.15.93","v5.15.92","v5.15.91","v5.15.90","v5.15.89","v5.15.88","v5.15.87","v5.15.86","v5.15.85","v5.15.84","v5.15.83","v5.15.82","v5.15.81","v5.15.80","v5.15.79","v5.15.78","v5.15.77","v5.15.76","v5.15.75","v5.15.74","v5.15.73","v5.15.72","v5.15.71","v5.15.70","v5.15.69","v5.15.68","v5.15.67","v5.15.66","v5.15.65","v5.15.64","v5.15.63","v5.15.62","v5.15.61","v5.15.60","v5.15.59","v5.15.58","v5.15.57","v5.15.56","v5.15.55","v5.15.54","v5.15.53","v5.15.52","v5.15.51","v5.15.50","v5.15.49","v5.15.48","v5.15.47","v5.15.46","v5.15.45","v5.15.44","v5.15.43","v5.15.42","v5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