{"id":"CVE-2024-50140","summary":"sched/core: Disable page allocation in task_tick_mm_cid()","details":"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-\u003e__lock ]\n   -\u003e task_tick_mm_cid()\n    -\u003e task_work_add()\n     -\u003e __kasan_record_aux_stack()\n      -\u003e kasan_save_stack()\n       -\u003e stack_depot_save_flags()\n        -\u003e alloc_pages_mpol_noprof()\n         -\u003e __alloc_pages_noprof()\n\t  -\u003e get_page_from_freelist()\n\t   -\u003e rmqueue()\n\t    -\u003e rmqueue_pcplist()\n\t     -\u003e __rmqueue_pcplist()\n\t      -\u003e rmqueue_bulk()\n\t       -\u003e 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.","modified":"2026-04-16T04:31:20.286910072Z","published":"2024-11-07T09:31:17.379Z","related":["SUSE-SU-2025:01919-1","SUSE-SU-2025:01951-1","SUSE-SU-2025:01967-1","SUSE-SU-2025:1177-1","SUSE-SU-2025:1178-1","SUSE-SU-2025:1180-1","SUSE-SU-2025:20190-1","SUSE-SU-2025:20192-1","SUSE-SU-2025:20260-1","SUSE-SU-2025:20270-1","USN-7276-1","USN-7277-1","openSUSE-SU-2024:14500-1","openSUSE-SU-2025:14705-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50140.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/509c29d0d26f68a6f6d0a05cb1a89725237e2b87"},{"type":"WEB","url":"https://git.kernel.org/stable/c/73ab05aa46b02d96509cb029a8d04fca7bbde8c7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ce0241ef83eed55f675376e8a3605d23de53d875"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50140.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-50140"},{"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":"223baf9d17f25e2608dbdff7232c095c1e612268"},{"fixed":"509c29d0d26f68a6f6d0a05cb1a89725237e2b87"},{"fixed":"ce0241ef83eed55f675376e8a3605d23de53d875"},{"fixed":"73ab05aa46b02d96509cb029a8d04fca7bbde8c7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50140.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}