{"cve":"CVE-2022-50648","nvd":{"published":"2025-12-09T01:16:47.490","modified":"2026-06-17T05:23:55.767","status":"Deferred","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nftrace: Fix recursive locking direct_mutex in ftrace_modify_direct_caller\n\nNaveen reported recursive locking of direct_mutex with sample\nftrace-direct-modify.ko:\n\n[   74.762406] WARNING: possible recursive locking detected\n[   74.762887] 6.0.0-rc6+ #33 Not tainted\n[   74.763216] --------------------------------------------\n[   74.763672] event-sample-fn/1084 is trying to acquire lock:\n[   74.764152] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \\\n    register_ftrace_function+0x1f/0x180\n[   74.764922]\n[   74.764922] but task is already holding lock:\n[   74.765421] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \\\n    modify_ftrace_direct+0x34/0x1f0\n[   74.766142]\n[   74.766142] other info that might help us debug this:\n[   74.766701]  Possible unsafe locking scenario:\n[   74.766701]\n[   74.767216]        CPU0\n[   74.767437]        ----\n[   74.767656]   lock(direct_mutex);\n[   74.767952]   lock(direct_mutex);\n[   74.768245]\n[   74.768245]  *** DEADLOCK ***\n[   74.768245]\n[   74.768750]  May be due to missing lock nesting notation\n[   74.768750]\n[   74.769332] 1 lock held by event-sample-fn/1084:\n[   74.769731]  #0: ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \\\n    modify_ftrace_direct+0x34/0x1f0\n[   74.770496]\n[   74.770496] stack backtrace:\n[   74.770884] CPU: 4 PID: 1084 Comm: event-sample-fn Not tainted ...\n[   74.771498] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ...\n[   74.772474] Call Trace:\n[   74.772696]  <TASK>\n[   74.772896]  dump_stack_lvl+0x44/0x5b\n[   74.773223]  __lock_acquire.cold.74+0xac/0x2b7\n[   74.773616]  lock_acquire+0xd2/0x310\n[   74.773936]  ? register_ftrace_function+0x1f/0x180\n[   74.774357]  ? lock_is_held_type+0xd8/0x130\n[   74.774744]  ? my_tramp2+0x11/0x11 [ftrace_direct_modify]\n[   74.775213]  __mutex_lock+0x99/0x1010\n[   74.775536]  ? register_ftrace_function+0x1f/0x180\n[   74.775954]  ? slab_free_freelist_hook.isra.43+0x115/0x160\n[   74.776424]  ? ftrace_set_hash+0x195/0x220\n[   74.776779]  ? register_ftrace_function+0x1f/0x180\n[   74.777194]  ? kfree+0x3e1/0x440\n[   74.777482]  ? my_tramp2+0x11/0x11 [ftrace_direct_modify]\n[   74.777941]  ? __schedule+0xb40/0xb40\n[   74.778258]  ? register_ftrace_function+0x1f/0x180\n[   74.778672]  ? my_tramp1+0xf/0xf [ftrace_direct_modify]\n[   74.779128]  register_ftrace_function+0x1f/0x180\n[   74.779527]  ? ftrace_set_filter_ip+0x33/0x70\n[   74.779910]  ? __schedule+0xb40/0xb40\n[   74.780231]  ? my_tramp1+0xf/0xf [ftrace_direct_modify]\n[   74.780678]  ? my_tramp2+0x11/0x11 [ftrace_direct_modify]\n[   74.781147]  ftrace_modify_direct_caller+0x5b/0x90\n[   74.781563]  ? 0xffffffffa0201000\n[   74.781859]  ? my_tramp1+0xf/0xf [ftrace_direct_modify]\n[   74.782309]  modify_ftrace_direct+0x1b2/0x1f0\n[   74.782690]  ? __schedule+0xb40/0xb40\n[   74.783014]  ? simple_thread+0x2a/0xb0 [ftrace_direct_modify]\n[   74.783508]  ? __schedule+0xb40/0xb40\n[   74.783832]  ? my_tramp2+0x11/0x11 [ftrace_direct_modify]\n[   74.784294]  simple_thread+0x76/0xb0 [ftrace_direct_modify]\n[   74.784766]  kthread+0xf5/0x120\n[   74.785052]  ? kthread_complete_and_exit+0x20/0x20\n[   74.785464]  ret_from_fork+0x22/0x30\n[   74.785781]  </TASK>\n\nFix this by using register_ftrace_function_nolock in\nftrace_modify_direct_caller.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/2482eacb685b6500e158268befbe6c90de5f166a","https://git.kernel.org/stable/c/9d2ce78ddcee159eb6a97449e9c68b6d60b9cec4"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:16:40.427100871+00:00"},"epss":{"cve":"CVE-2022-50648","score":0.00185,"percentile":0.08087,"date":"2026-10-31"},"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."]}