CVE-2025-39767
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-11

Last updated on: 2025-11-25

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: LoongArch: Optimize module load time by optimizing PLT/GOT counting When enabling CONFIG_KASAN, CONFIG_PREEMPT_VOLUNTARY_BUILD and CONFIG_PREEMPT_VOLUNTARY at the same time, there will be soft deadlock, the relevant logs are as follows: rcu: INFO: rcu_sched self-detected stall on CPU ... Call Trace: [<900000000024f9e4>] show_stack+0x5c/0x180 [<90000000002482f4>] dump_stack_lvl+0x94/0xbc [<9000000000224544>] rcu_dump_cpu_stacks+0x1fc/0x280 [<900000000037ac80>] rcu_sched_clock_irq+0x720/0xf88 [<9000000000396c34>] update_process_times+0xb4/0x150 [<90000000003b2474>] tick_nohz_handler+0xf4/0x250 [<9000000000397e28>] __hrtimer_run_queues+0x1d0/0x428 [<9000000000399b2c>] hrtimer_interrupt+0x214/0x538 [<9000000000253634>] constant_timer_interrupt+0x64/0x80 [<9000000000349938>] __handle_irq_event_percpu+0x78/0x1a0 [<9000000000349a78>] handle_irq_event_percpu+0x18/0x88 [<9000000000354c00>] handle_percpu_irq+0x90/0xf0 [<9000000000348c74>] handle_irq_desc+0x94/0xb8 [<9000000001012b28>] handle_cpu_irq+0x68/0xa0 [<9000000001def8c0>] handle_loongarch_irq+0x30/0x48 [<9000000001def958>] do_vint+0x80/0xd0 [<9000000000268a0c>] kasan_mem_to_shadow.part.0+0x2c/0x2a0 [<90000000006344f4>] __asan_load8+0x4c/0x120 [<900000000025c0d0>] module_frob_arch_sections+0x5c8/0x6b8 [<90000000003895f0>] load_module+0x9e0/0x2958 [<900000000038b770>] __do_sys_init_module+0x208/0x2d0 [<9000000001df0c34>] do_syscall+0x94/0x190 [<900000000024d6fc>] handle_syscall+0xbc/0x158 After analysis, this is because the slow speed of loading the amdgpu module leads to the long time occupation of the cpu and then the soft deadlock. When loading a module, module_frob_arch_sections() tries to figure out the number of PLTs/GOTs that will be needed to handle all the RELAs. It will call the count_max_entries() to find in an out-of-order date which counting algorithm has O(n^2) complexity. To make it faster, we sort the relocation list by info and addend. That way, to check for a duplicate relocation, it just needs to compare with the previous entry. This reduces the complexity of the algorithm to O(n log n), as done in commit d4e0340919fb ("arm64/module: Optimize module load time by optimizing PLT counting"). This gives sinificant reduction in module load time for modules with large number of relocations. After applying this patch, the soft deadlock problem has been solved, and the kernel starts normally without "Call Trace". Using the default configuration to test some modules, the results are as follows: Module Size ip_tables 36K fat 143K radeon 2.5MB amdgpu 16MB Without this patch: Module Module load time (ms) Count(PLTs/GOTs) ip_tables 18 59/6 fat 0 162/14 radeon 54 1221/84 amdgpu 1411 4525/1098 With this patch: Module Module load time (ms) Count(PLTs/GOTs) ip_tables 18 59/6 fat 0 162/14 radeon 22 1221/84 amdgpu 45 4525/1098
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Meta Information
Published
2025-09-11
Last Modified
2025-11-25
Generated
2026-05-07
AI Q&A
2025-09-11
EPSS Evaluated
2026-05-05
NVD
CVE-2025-39767
Affected Vendors & Products
Showing 5 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-667 The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel when enabling CONFIG_KASAN, CONFIG_PREEMPT_VOLUNTARY_BUILD, and CONFIG_PREEMPT_VOLUNTARY simultaneously, causing a soft deadlock due to slow module loading, particularly with the amdgpu module. The slow loading is caused by an inefficient O(n^2) algorithm used to count PLTs/GOTs during module loading. The issue was fixed by optimizing the counting algorithm to O(n log n) by sorting the relocation list, which significantly reduces module load time and prevents the soft deadlock.


How can this vulnerability impact me? :

This vulnerability can cause a soft deadlock in the Linux kernel, leading to the system becoming unresponsive or stalled during module loading, especially for large modules like amdgpu. This can affect system stability and availability until the module loading completes or the system is restarted.


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

This vulnerability can be detected by observing soft deadlock symptoms in the Linux kernel logs when loading modules with specific kernel configurations enabled (CONFIG_KASAN, CONFIG_PREEMPT_VOLUNTARY_BUILD, and CONFIG_PREEMPT_VOLUNTARY). Relevant logs include messages like 'rcu: INFO: rcu_sched self-detected stall on CPU' followed by a call trace. To detect this, you can check the kernel logs using commands such as 'dmesg | grep rcu' or 'journalctl -k | grep rcu' to look for these stall messages and call traces during module loading.


What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, apply the patch that optimizes the module load time by sorting the relocation list and reducing the complexity of the counting algorithm from O(n^2) to O(n log n). This patch resolves the soft deadlock issue by significantly reducing module load time, especially for large modules like amdgpu. Until the patch is applied, avoid loading large modules that trigger the deadlock or disable the combination of CONFIG_KASAN, CONFIG_PREEMPT_VOLUNTARY_BUILD, and CONFIG_PREEMPT_VOLUNTARY kernel options if possible.


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