On Thu, Mar 12, 2020 at 06:57:34PM +0530, Santosh Sivaraj wrote:
The TLB flush optimisation (a46cc7a90f: powerpc/mm/radix: Improve TLB/PWC flushes) may result in random memory corruption. Any concurrent page-table walk could end up with a Use-after-Free. Even on UP this might give issues, since mmu_gather is preemptible these days. An interrupt or preempted task accessing user pages might stumble into the free page if the hardware caches page directories.
The series is a backport of the fix sent by Peter .
The first three patches are dependencies for the last patch (avoid potential double flush). If the performance impact due to double flush is considered trivial then the first three patches and last patch may be dropped.
This is only for v4.19 stable.
Sorry for the delay, now queued up, let's see what the test-builders say about it...