GHSA-JCQ2-873M-MP53
Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-22 18:30In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix race between update_event_fields and, event_define_fields
The following sequence may leads race between event_define_fields() and update_event_fields():
CPU0 (loads module A) CPU1 (loads module B) =============================== =============================== load_module(A) load_module(B) notifier_call_chain notifier_call_chain trace_module_notify trace_module_notify mutex_lock(&event_mutex) trace_event_update_all() trace_module_add_events(A) down_write(&trace_event_sem) __register_event(call_A) __add_event_to_tracers(call_A) event_define_fields(call_A) for each f: list_for_each_entry(field, list_add(&f->link, &class->fields, link) &class->fields) field = class->fields->next;
Where access to the class->fields is not protected by the event_mutex in trace_event_update_all().
This produces the following panic: Unable to handle kernel access ... at virtual address 0000000000000018 pc : update_event_fields+0xf8/0x368 Call trace: update_event_fields+0xf8/0x368 trace_event_update_all+0x7c/0x2b4 trace_module_notify+0x4c/0x1dc notifier_call_chain+0x84/0x168 blocking_notifier_call_chain_robust+0x64/0xd4 load_module+0x10c8/0x123c __arm64_sys_finit_module+0x230/0x31c
Fix by taking event_mutex in trace_event_update_all() before trace_event_sem.
{
"affected": [],
"aliases": [
"CVE-2026-74636"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-22T16:16:36Z",
"severity": null
},
"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(\u0026event_mutex) trace_event_update_all()\n trace_module_add_events(A) down_write(\u0026trace_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(\u0026f-\u003elink, \u0026class-\u003efields, link)\n \u0026class-\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.",
"id": "GHSA-jcq2-873m-mp53",
"modified": "2026-08-22T18:30:27Z",
"published": "2026-08-22T18:30:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74636"
},
{
"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"
}
],
"schema_version": "1.4.0",
"severity": []
}
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