CVE-2026-43292

About vulnerability

In the Linux kernel, the following vulnerability has been resolved: mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node When CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during vmalloc cleanup triggers expensive stack unwinding that acquires RCU read locks. Processing a large purge_list without rescheduling can cause the task to hold CPU for extended periods (10+ seconds), leading to RCU stalls and potential OOM conditions. The issue manifests in purge_vmap_node() -> kasan_release_vmalloc_node() where iterating through hundreds or thousands of vmap_area entries and freeing their associated shadow pages causes: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l … task:kworker/0:17 state:R running task stack:28840 pid:6229 … kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299 purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299 Each call to kasan_release_vmalloc() can free many pages, and with page_owner tracking, each free triggers save_stack() which performs stack unwinding under RCU read lock. Without yielding, this creates an unbounded RCU critical section. Add periodic cond_resched() calls within the loop to allow:

• RCU grace periods to complete
• Other tasks to run
• Scheduler to preempt when needed The fix uses need_resched() for immediate response under load, with a batch count of 32 as a guaranteed upper bound to prevent worst-case stalls even under light load. A flaw was found in the Linux kernel. When the CONFIG_PAGE_OWNER option is enabled, the kernel’s memory management (mm/vmalloc) component can experience Read-Copy-Update (RCU) stalls during virtual memory allocation cleanup. This occurs because freeing Kernel Address Sanitizer (KASAN) shadow pages triggers expensive stack unwinding operations that acquire RCU read locks. Processing a large number of pages without yielding the CPU can cause tasks to hold the CPU for extended periods, leading to RCU stalls and potential Out-Of-Memory (OOM) conditions, effectively resulting in a Denial of Service.

Live-patch status from KernelCare for each operating system.