CVE-2024-49854

In the Linux kernel, the following vulnerability has been resolved: block, bfq: fix uaf for accessing waker_bfqq after splitting After commit 42c306ed7233 ("block, bfq: don't break merge chain in bfq_split_bfqq()"), if the current procress is the last holder of bfqq, the bfqq can be freed after bfq_split_bfqq(). Hence recored the bfqq and then access bfqq->waker_bfqq may trigger UAF. What's more, the waker_bfqq may in the merge chain of bfqq, hence just recored waker_bfqq is still not safe. Fix the problem by adding a helper bfq_waker_bfqq() to check if bfqq->waker_bfqq is in the merge chain, and current procress is the only holder.

• linux linux kernel (>= 5.10.227 < 5.15.168) • linux linux kernel (>= 5.16 < 6.1.113) • linux linux kernel (>= 6.2 < 6.6.54) • linux linux kernel (>= 6.7 < 6.10.13) • linux linux kernel (>= 6.11 < 6.11.2)