CVE-2025-68322
Description
In the Linux kernel, the following vulnerability has been resolved:
parisc: Avoid crash due to unaligned access in unwinder
Guenter Roeck reported this kernel crash on his emulated B160L machine:
Starting network: udhcpc: started, v1.36.1 Backtrace: [<104320d4>] unwind_once+0x1c/0x5c [<10434a00>] walk_stackframe.isra.0+0x74/0xb8 [<10434a6c>] arch_stack_walk+0x28/0x38 [<104e5efc>] stack_trace_save+0x48/0x5c [<105d1bdc>] set_track_prepare+0x44/0x6c [<105d9c80>] ___slab_alloc+0xfc4/0x1024 [<105d9d38>] __slab_alloc.isra.0+0x58/0x90 [<105dc80c>] kmem_cache_alloc_noprof+0x2ac/0x4a0 [<105b8e54>] __anon_vma_prepare+0x60/0x280 [<105a823c>] __vmf_anon_prepare+0x68/0x94 [<105a8b34>] do_wp_page+0x8cc/0xf10 [<105aad88>] handle_mm_fault+0x6c0/0xf08 [<10425568>] do_page_fault+0x110/0x440 [<10427938>] handle_interruption+0x184/0x748 [<11178398>] schedule+0x4c/0x190 BUG: spinlock recursion on CPU#0, ifconfig/2420 lock: terminate_lock.2+0x0/0x1c, .magic: dead4ead, .owner: ifconfig/2420, .owner_cpu: 0
While creating the stack trace, the unwinder uses the stack pointer to guess the previous frame to read the previous stack pointer from memory. The crash happens, because the unwinder tries to read from unaligned memory and as such triggers the unalignment trap handler which then leads to the spinlock recursion and finally to a deadlock.
Fix it by checking the alignment before accessing the memory.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
In the Linux kernel, the parisc unwinder crashes due to unaligned memory access, leading to a spinlock recursion and deadlock.
Vulnerability
Description
In the Linux kernel, the parisc architecture's unwinder function unwindowing function unwind_once` can cause a kernel crash due to unaligned memory access. The unwinder uses the stack pointer to guess the previous frame and reads the previous stack pointer from memory. If the memory address is not properly aligned, it triggers an unalignment trap handler, which can lead to spinlock recursion and ultimately a deadlock. This issue was reported by Guenter Roeck on an emulated B160L machine during network initialization.
Exploitation
An attacker with local access to a parisc system could potentially trigger this vulnerability by causing the kernel to perform unwinding during a stack trace, such as during a kernel panic or other error handling. The crash occurs when the unwinder attempts to read from unaligned memory, which can be induced by specific stack conditions. No special privileges are required beyond the ability to trigger a stack trace.
Impact
Successful exploitation leads to a kernel crash (deadlock) due to spinlock recursion, causing a denial of service (DoS) condition. The system becomes unresponsive and requires a reboot. There is no evidence of privilege escalation or data corruption.
Mitigation
The fix is to check the alignment of the memory address before accessing it in the unwinder. The patch has been applied to the Linux kernel stable branches [1][2][3]. Users should update to a kernel version containing the fix.
AI Insight generated on May 19, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
1Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
3News mentions
0No linked articles in our index yet.