CVE-2025-39833
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-16

Last updated on: 2025-12-03

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: mISDN: hfcpci: Fix warning when deleting uninitialized timer With CONFIG_DEBUG_OBJECTS_TIMERS unloading hfcpci module leads to the following splat: [ 250.215892] ODEBUG: assert_init not available (active state 0) object: ffffffffc01a3dc0 object type: timer_list hint: 0x0 [ 250.217520] WARNING: CPU: 0 PID: 233 at lib/debugobjects.c:612 debug_print_object+0x1b6/0x2c0 [ 250.218775] Modules linked in: hfcpci(-) mISDN_core [ 250.219537] CPU: 0 UID: 0 PID: 233 Comm: rmmod Not tainted 6.17.0-rc2-g6f713187ac98 #2 PREEMPT(voluntary) [ 250.220940] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 250.222377] RIP: 0010:debug_print_object+0x1b6/0x2c0 [ 250.223131] Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4f 41 56 48 8b 14 dd a0 4e 01 9f 48 89 ee 48 c7 c7 20 46 01 9f e8 cb 84d [ 250.225805] RSP: 0018:ffff888015ea7c08 EFLAGS: 00010286 [ 250.226608] RAX: 0000000000000000 RBX: 0000000000000005 RCX: ffffffff9be93a95 [ 250.227708] RDX: 1ffff1100d945138 RSI: 0000000000000008 RDI: ffff88806ca289c0 [ 250.228993] RBP: ffffffff9f014a00 R08: 0000000000000001 R09: ffffed1002bd4f39 [ 250.230043] R10: ffff888015ea79cf R11: 0000000000000001 R12: 0000000000000001 [ 250.231185] R13: ffffffff9eea0520 R14: 0000000000000000 R15: ffff888015ea7cc8 [ 250.232454] FS: 00007f3208f01540(0000) GS:ffff8880caf5a000(0000) knlGS:0000000000000000 [ 250.233851] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 250.234856] CR2: 00007f32090a7421 CR3: 0000000004d63000 CR4: 00000000000006f0 [ 250.236117] Call Trace: [ 250.236599] <TASK> [ 250.236967] ? trace_irq_enable.constprop.0+0xd4/0x130 [ 250.237920] debug_object_assert_init+0x1f6/0x310 [ 250.238762] ? __pfx_debug_object_assert_init+0x10/0x10 [ 250.239658] ? __lock_acquire+0xdea/0x1c70 [ 250.240369] __try_to_del_timer_sync+0x69/0x140 [ 250.241172] ? __pfx___try_to_del_timer_sync+0x10/0x10 [ 250.242058] ? __timer_delete_sync+0xc6/0x120 [ 250.242842] ? lock_acquire+0x30/0x80 [ 250.243474] ? __timer_delete_sync+0xc6/0x120 [ 250.244262] __timer_delete_sync+0x98/0x120 [ 250.245015] HFC_cleanup+0x10/0x20 [hfcpci] [ 250.245704] __do_sys_delete_module+0x348/0x510 [ 250.246461] ? __pfx___do_sys_delete_module+0x10/0x10 [ 250.247338] do_syscall_64+0xc1/0x360 [ 250.247924] entry_SYSCALL_64_after_hwframe+0x77/0x7f Fix this by initializing hfc_tl timer with DEFINE_TIMER macro. Also, use mod_timer instead of manual timeout update.
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Meta Information
Published
2025-09-16
Last Modified
2025-12-03
Generated
2026-05-07
AI Q&A
2025-09-16
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 2.6.29 (inc) to 6.16.5 (exc)
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
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CWE ID Description
CWE-908 The product uses or accesses a resource that has not been initialized.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is related to the Linux kernel's mISDN hfcpci module. When unloading the hfcpci module with CONFIG_DEBUG_OBJECTS_TIMERS enabled, a warning occurs due to deleting an uninitialized timer. This leads to a kernel warning and potential instability. The issue is caused by the timer not being properly initialized before deletion. The fix involves initializing the timer with the DEFINE_TIMER macro and using mod_timer instead of manually updating the timeout.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by checking the system logs for the specific warning messages related to the hfcpci module and timer deletion issues. Look for kernel log entries containing 'ODEBUG: assert_init not available' and warnings from 'debug_print_object' related to the hfcpci module. You can use the following command to search the kernel logs: sudo dmesg | grep -E 'ODEBUG|hfcpci|debug_print_object'. Additionally, monitoring for splat or warning messages when unloading the hfcpci module (e.g., using rmmod) can indicate the presence of this issue.


What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability immediately, update the Linux kernel to a version where the hfcpci module timer initialization is fixed by using the DEFINE_TIMER macro and mod_timer instead of manual timeout updates. If updating is not immediately possible, avoid unloading the hfcpci module when CONFIG_DEBUG_OBJECTS_TIMERS is enabled to prevent the warning and potential instability.


How can this vulnerability impact me? :

This vulnerability can cause kernel warnings and instability when unloading the hfcpci module, potentially leading to system crashes or unexpected behavior. It affects system reliability but does not directly indicate a security breach or data compromise.


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