{"id":"CVE-2024-50140","url":"https://www.cyber-defence.io/tools/cve/CVE-2024-50140","generatedAt":"2026-10-28T02:13:52.288Z","title":"In the Linux kernel, the following vulnerability has been resolved: sched/core: Disable page allocation in task_tick_mm_cid() With KASAN and PREEMPT_RT enabled, calling task_work_add() in task_tick_mm_cid() may cause the following splat. [ 63.696416]…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/core: Disable page allocation in task_tick_mm_cid()\n\nWith KASAN and PREEMPT_RT enabled, calling task_work_add() in\ntask_tick_mm_cid() may cause the following splat.\n\n[   63.696416] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48\n[   63.696416] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 610, name: modprobe\n[   63.696416] preempt_count: 10001, expected: 0\n[   63.696416] RCU nest depth: 1, expected: 1\n\nThis problem is caused by the following call trace.\n\n  sched_tick() [ acquire rq->__lock ]\n   -> task_tick_mm_cid()\n    -> task_work_add()\n     -> __kasan_record_aux_stack()\n      -> kasan_save_stack()\n       -> stack_depot_save_flags()\n        -> alloc_pages_mpol_noprof()\n         -> __alloc_pages_noprof()\n\t  -> get_page_from_freelist()\n\t   -> rmqueue()\n\t    -> rmqueue_pcplist()\n\t     -> __rmqueue_pcplist()\n\t      -> rmqueue_bulk()\n\t       -> rt_spin_lock()\n\nThe rq lock is a raw_spinlock_t. We can't sleep while holding\nit. IOW, we can't call alloc_pages() in stack_depot_save_flags().\n\nThe task_tick_mm_cid() function with its task_work_add() call was\nintroduced by commit 223baf9d17f2 (\"sched: Fix performance regression\nintroduced by mm_cid\") in v6.4 kernel.\n\nFortunately, there is a kasan_record_aux_stack_noalloc() variant that\ncalls stack_depot_save_flags() while not allowing it to allocate\nnew pages.  To allow task_tick_mm_cid() to use task_work without\npage allocation, a new TWAF_NO_ALLOC flag is added to enable calling\nkasan_record_aux_stack_noalloc() instead of kasan_record_aux_stack()\nif set. The task_tick_mm_cid() function is modified to add this new flag.\n\nThe possible downside is the missing stack trace in a KASAN report due\nto new page allocation required when task_work_add_noallloc() is called\nwhich should be rare.","published":"2024-11-07T10:15:06.000Z","lastModified":"2026-06-17T08:03:41.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["linux/linux kernel"],"epss":{"score":0.00231,"percentile":0.13835,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/509c29d0d26f68a6f6d0a05cb1a89725237e2b87","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/73ab05aa46b02d96509cb029a8d04fca7bbde8c7","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ce0241ef83eed55f675376e8a3605d23de53d875","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2024-50140","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}