Bug 2422790 (CVE-2025-68322)

Summary:	CVE-2025-68322 kernel: parisc: Avoid crash due to unaligned access in unwinder
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	unspecified	Keywords:	Security
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Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2025-12-16 16:01:39 UTC

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.

Comment 1 Alexander B 2025-12-16 20:08:51 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025121622-CVE-2025-68322-b034@gregkh/T