{"uuid": "0dc82b9c-8467-4695-93a1-e7a59f861487", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2025-37878", "type": "seen", "source": "https://t.me/DarkWebInformer_CVEAlerts/15694", "content": "\ud83d\udd17 DarkWebInformer.com - Cyber Threat Intelligence\n\ud83d\udccc CVE ID: CVE-2025-37878\n\ud83d\udd25 CVSS Score: N/A\n\ud83d\udd39 Description: In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Fix WARN_ON(!ctx) in __free_event() for partial init\n\nMove the get_ctx(child_ctx) call and the child_event->ctx assignment to\noccur immediately after the child event is allocated. Ensure that\nchild_event->ctx is non-NULL before any subsequent error path within\ninherit_event calls free_event(), satisfying the assumptions of the\ncleanup code.\n\nDetails:\n\nThere's no clear Fixes tag, because this bug is a side-effect of\nmultiple interacting commits over time (up to 15 years old), not\na single regression.\n\nThe code initially incremented refcount then assigned context\nimmediately after the child_event was created. Later, an early\nvalidity check for child_event was added before the\nrefcount/assignment. Even later, a WARN_ON_ONCE() cleanup check was\nadded, assuming event->ctx is valid if the pmu_ctx is valid.\nThe problem is that the WARN_ON_ONCE() could trigger after the initial\ncheck passed but before child_event->ctx was assigned, violating its\nprecondition. The solution is to assign child_event->ctx right after\nits initial validation. This ensures the context exists for any\nsubsequent checks or cleanup routines, resolving the WARN_ON_ONCE().\n\nTo resolve it, defer the refcount update and child_event->ctx assignment\ndirectly after child_event->pmu_ctx is set but before checking if the\nparent event is orphaned. The cleanup routine depends on\nevent->pmu_ctx being non-NULL before it verifies event->ctx is\nnon-NULL. This also maintains the author's original intent of passing\nin child_ctx to find_get_pmu_context before its refcount/assignment.\n\n[ mingo: Expanded the changelog from another email by Gabriel Shahrouzi. ]\n\ud83d\udccf Published: 2025-05-09T06:45:42.459Z\n\ud83d\udccf Modified: 2025-05-09T06:45:42.459Z\n\ud83d\udd17 References:\n1. https://git.kernel.org/stable/c/1fe9b92eede32574dbe05b5bdb6ad666b350bed0\n2. https://git.kernel.org/stable/c/90dc6c1e3b200812da8d0aa030e1b7fda8226d0e\n3. https://git.kernel.org/stable/c/cb56cd11feabf99e08bc18960700a53322ffcea7\n4. https://git.kernel.org/stable/c/0ba3a4ab76fd3367b9cb680cad70182c896c795c", "creation_timestamp": "2025-05-09T07:25:40.000000Z"}