In the Linux kernel, the following vulnerability has been resolved:mm/kmemleak: avoid deadlock by moving pr_warn() outside kmemleak_lockWhen netpoll is enabled, calling pr_warn_once() while holdingkmemleak_lock in mem_pool_alloc() can cause a deadlock due to lockinversion with the netconsole subsystem. This occurs becausepr_warn_once() may trigger netpoll, which eventually leads to__alloc_skb() and back into kmemleak code, attempting to reacquirekmemleak_lock.This is the path for the deadlock.mem_pool_alloc() -> raw_spin_lock_irqsave(&kmemleak_lock, flags); -> pr_warn_once() -> netconsole subsystem -> netpoll -> __alloc_skb -> __create_object -> raw_spin_lock_irqsave(&kmemleak_lock, flags);Fix this by setting a flag and issuing the pr_warn_once() afterkmemleak_lock is released.
No PoCs from references.
- https://github.com/w4zu/Debian_security