In the Linux kernel, the following vulnerability has been resolved:

ftrace: Fix recursive locking direct_mutex in ftrace_modify_direct_caller

Naveen reported recursive locking of direct_mutex with sample
ftrace-direct-modify.ko:

[ 74.762406] WARNING: possible recursive locking detected
[ 74.762887] 6.0.0-rc6+ #33 Not tainted
[ 74.763216] --------------------------------------------
[ 74.763672] event-sample-fn/1084 is trying to acquire lock:
[ 74.764152] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \
register_ftrace_function+0x1f/0x180
[ 74.764922]
[ 74.764922] but task is already holding lock:
[ 74.765421] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \
modify_ftrace_direct+0x34/0x1f0
[ 74.766142]
[ 74.766142] other info that might help us debug this:
[ 74.766701] Possible unsafe locking scenario:
[ 74.766701]
[ 74.767216] CPU0
[ 74.767437] ----
[ 74.767656] lock(direct_mutex);
[ 74.767952] lock(direct_mutex);
[ 74.768245]
[ 74.768245] *** DEADLOCK ***
[ 74.768245]
[ 74.768750] May be due to missing lock nesting notation
[ 74.768750]
[ 74.769332] 1 lock held by event-sample-fn/1084:
[ 74.769731] #0: ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \
modify_ftrace_direct+0x34/0x1f0
[ 74.770496]
[ 74.770496] stack backtrace:
[ 74.770884] CPU: 4 PID: 1084 Comm: event-sample-fn Not tainted ...
[ 74.771498] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ...
[ 74.772474] Call Trace:
[ 74.772696] <TASK>
[ 74.772896] dump_stack_lvl+0x44/0x5b
[ 74.773223] __lock_acquire.cold.74+0xac/0x2b7
[ 74.773616] lock_acquire+0xd2/0x310
[ 74.773936] ? register_ftrace_function+0x1f/0x180
[ 74.774357] ? lock_is_held_type+0xd8/0x130
[ 74.774744] ? my_tramp2+0x11/0x11 [ftrace_direct_modify]
[ 74.775213] __mutex_lock+0x99/0x1010
[ 74.775536] ? register_ftrace_function+0x1f/0x180
[ 74.775954] ? slab_free_freelist_hook.isra.43+0x115/0x160
[ 74.776424] ? ftrace_set_hash+0x195/0x220
[ 74.776779] ? register_ftrace_function+0x1f/0x180
[ 74.777194] ? kfree+0x3e1/0x440
[ 74.777482] ? my_tramp2+0x11/0x11 [ftrace_direct_modify]
[ 74.777941] ? __schedule+0xb40/0xb40
[ 74.778258] ? register_ftrace_function+0x1f/0x180
[ 74.778672] ? my_tramp1+0xf/0xf [ftrace_direct_modify]
[ 74.779128] register_ftrace_function+0x1f/0x180
[ 74.779527] ? ftrace_set_filter_ip+0x33/0x70
[ 74.779910] ? __schedule+0xb40/0xb40
[ 74.780231] ? my_tramp1+0xf/0xf [ftrace_direct_modify]
[ 74.780678] ? my_tramp2+0x11/0x11 [ftrace_direct_modify]
[ 74.781147] ftrace_modify_direct_caller+0x5b/0x90
[ 74.781563] ? 0xffffffffa0201000
[ 74.781859] ? my_tramp1+0xf/0xf [ftrace_direct_modify]
[ 74.782309] modify_ftrace_direct+0x1b2/0x1f0
[ 74.782690] ? __schedule+0xb40/0xb40
[ 74.783014] ? simple_thread+0x2a/0xb0 [ftrace_direct_modify]
[ 74.783508] ? __schedule+0xb40/0xb40
[ 74.783832] ? my_tramp2+0x11/0x11 [ftrace_direct_modify]
[ 74.784294] simple_thread+0x76/0xb0 [ftrace_direct_modify]
[ 74.784766] kthread+0xf5/0x120
[ 74.785052] ? kthread_complete_and_exit+0x20/0x20
[ 74.785464] ret_from_fork+0x22/0x30
[ 74.785781] </TASK>

Fix this by using register_ftrace_function_nolock in
ftrace_modify_direct_caller.

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00027.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
53cd885bc5c3ea283cc9c00ca6446c778f00bfba affected < 2482eacb685b6500e158268befbe6c90de5f166a
53cd885bc5c3ea283cc9c00ca6446c778f00bfba affected < 9d2ce78ddcee159eb6a97449e9c68b6d60b9cec4
Linux Linux affected
Version Status Constraints
6.0 affected —
0 unaffected < 6.0
6.0.3 unaffected ≤ 6.0.*
6.1 unaffected ≤ *

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References
Link Providers
https://git.kernel.org/stable/c/2482eacb685b6500e158268befbe6c90de5f166a cve-icon cve-icon
https://git.kernel.org/stable/c/9d2ce78ddcee159eb6a97449e9c68b6d60b9cec4 cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025120937-CVE-2022-50648-ac1e@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2022-50648 cve-icon
https://www.cve.org/CVERecord?id=CVE-2022-50648 cve-icon
History

Wed, 10 Dec 2025 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low

Tue, 09 Dec 2025 00:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix recursive locking direct_mutex in ftrace_modify_direct_caller Naveen reported recursive locking of direct_mutex with sample ftrace-direct-modify.ko: [ 74.762406] WARNING: possible recursive locking detected [ 74.762887] 6.0.0-rc6+ #33 Not tainted [ 74.763216] -------------------------------------------- [ 74.763672] event-sample-fn/1084 is trying to acquire lock: [ 74.764152] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \ register_ftrace_function+0x1f/0x180 [ 74.764922] [ 74.764922] but task is already holding lock: [ 74.765421] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \ modify_ftrace_direct+0x34/0x1f0 [ 74.766142] [ 74.766142] other info that might help us debug this: [ 74.766701] Possible unsafe locking scenario: [ 74.766701] [ 74.767216] CPU0 [ 74.767437] ---- [ 74.767656] lock(direct_mutex); [ 74.767952] lock(direct_mutex); [ 74.768245] [ 74.768245] *** DEADLOCK *** [ 74.768245] [ 74.768750] May be due to missing lock nesting notation [ 74.768750] [ 74.769332] 1 lock held by event-sample-fn/1084: [ 74.769731] #0: ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \ modify_ftrace_direct+0x34/0x1f0 [ 74.770496] [ 74.770496] stack backtrace: [ 74.770884] CPU: 4 PID: 1084 Comm: event-sample-fn Not tainted ... [ 74.771498] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ... [ 74.772474] Call Trace: [ 74.772696] <TASK> [ 74.772896] dump_stack_lvl+0x44/0x5b [ 74.773223] __lock_acquire.cold.74+0xac/0x2b7 [ 74.773616] lock_acquire+0xd2/0x310 [ 74.773936] ? register_ftrace_function+0x1f/0x180 [ 74.774357] ? lock_is_held_type+0xd8/0x130 [ 74.774744] ? my_tramp2+0x11/0x11 [ftrace_direct_modify] [ 74.775213] __mutex_lock+0x99/0x1010 [ 74.775536] ? register_ftrace_function+0x1f/0x180 [ 74.775954] ? slab_free_freelist_hook.isra.43+0x115/0x160 [ 74.776424] ? ftrace_set_hash+0x195/0x220 [ 74.776779] ? register_ftrace_function+0x1f/0x180 [ 74.777194] ? kfree+0x3e1/0x440 [ 74.777482] ? my_tramp2+0x11/0x11 [ftrace_direct_modify] [ 74.777941] ? __schedule+0xb40/0xb40 [ 74.778258] ? register_ftrace_function+0x1f/0x180 [ 74.778672] ? my_tramp1+0xf/0xf [ftrace_direct_modify] [ 74.779128] register_ftrace_function+0x1f/0x180 [ 74.779527] ? ftrace_set_filter_ip+0x33/0x70 [ 74.779910] ? __schedule+0xb40/0xb40 [ 74.780231] ? my_tramp1+0xf/0xf [ftrace_direct_modify] [ 74.780678] ? my_tramp2+0x11/0x11 [ftrace_direct_modify] [ 74.781147] ftrace_modify_direct_caller+0x5b/0x90 [ 74.781563] ? 0xffffffffa0201000 [ 74.781859] ? my_tramp1+0xf/0xf [ftrace_direct_modify] [ 74.782309] modify_ftrace_direct+0x1b2/0x1f0 [ 74.782690] ? __schedule+0xb40/0xb40 [ 74.783014] ? simple_thread+0x2a/0xb0 [ftrace_direct_modify] [ 74.783508] ? __schedule+0xb40/0xb40 [ 74.783832] ? my_tramp2+0x11/0x11 [ftrace_direct_modify] [ 74.784294] simple_thread+0x76/0xb0 [ftrace_direct_modify] [ 74.784766] kthread+0xf5/0x120 [ 74.785052] ? kthread_complete_and_exit+0x20/0x20 [ 74.785464] ret_from_fork+0x22/0x30 [ 74.785781] </TASK> Fix this by using register_ftrace_function_nolock in ftrace_modify_direct_caller.
Title ftrace: Fix recursive locking direct_mutex in ftrace_modify_direct_caller
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-12-09T00:00:22.410Z

Reserved: 2025-12-08T23:57:43.371Z

Link: CVE-2022-50648

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-12-09T01:16:47.490

Modified: 2025-12-09T18:37:13.640

Link: CVE-2022-50648

cve-icon Redhat

Severity : Low

Publid Date: 2025-12-09T00:00:00Z

Links: CVE-2022-50648 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

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