{"cve":"CVE-2025-39737","nvd":{"published":"2025-09-11T17:15:35.173","modified":"2026-10-19T21:10:00.160","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/kmemleak: avoid soft lockup in __kmemleak_do_cleanup()\n\nA soft lockup warning was observed on a relative small system x86-64\nsystem with 16 GB of memory when running a debug kernel with kmemleak\nenabled.\n\n  watchdog: BUG: soft lockup - CPU#8 stuck for 33s! [kworker/8:1:134]\n\nThe test system was running a workload with hot unplug happening in\nparallel.  Then kemleak decided to disable itself due to its inability to\nallocate more kmemleak objects.  The debug kernel has its\nCONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE set to 40,000.\n\nThe soft lockup happened in kmemleak_do_cleanup() when the existing\nkmemleak objects were being removed and deleted one-by-one in a loop via a\nworkqueue.  In this particular case, there are at least 40,000 objects\nthat need to be processed and given the slowness of a debug kernel and the\nfact that a raw_spinlock has to be acquired and released in\n__delete_object(), it could take a while to properly handle all these\nobjects.\n\nAs kmemleak has been disabled in this case, the object removal and\ndeletion process can be further optimized as locking isn't really needed. \nHowever, it is probably not worth the effort to optimize for such an edge\ncase that should rarely happen.  So the simple solution is to call\ncond_resched() at periodic interval in the iteration loop to avoid soft\nlockup.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-401"],"references":["https://git.kernel.org/stable/c/1ef72a7fedc5bca70e8cc980985790de10d407aa","https://git.kernel.org/stable/c/8d2d22a55ffe35c38e69795468a7addd1a80e9ce","https://git.kernel.org/stable/c/926092268efdf1ed7b55cf486356c74a9e7710d1","https://git.kernel.org/stable/c/9b80430c194e4a114dc663c1025d56b4f3d0153d","https://git.kernel.org/stable/c/9f1f4e95031f84867c5821540466d62f88dab8ca"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-39737","score":0.00176,"percentile":0.07036,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}