{"id":"CVE-2022-50648","summary":"ftrace: Fix recursive locking direct_mutex in ftrace_modify_direct_caller","details":"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]  \u003cTASK\u003e\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]  \u003c/TASK\u003e\n\nFix this by using register_ftrace_function_nolock in\nftrace_modify_direct_caller.","modified":"2026-04-02T08:28:40.798838Z","published":"2025-12-09T00:00:22.410Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50648.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2482eacb685b6500e158268befbe6c90de5f166a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9d2ce78ddcee159eb6a97449e9c68b6d60b9cec4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50648.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-50648"},{"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":"53cd885bc5c3ea283cc9c00ca6446c778f00bfba"},{"fixed":"2482eacb685b6500e158268befbe6c90de5f166a"},{"fixed":"9d2ce78ddcee159eb6a97449e9c68b6d60b9cec4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50648.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.0.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50648.json"}}],"schema_version":"1.7.5"}