On Thu, 18 Jan 2024 at 12:28, Charan Teja Kalla <quic_charante@xxxxxxxxxxx> wrote: > > May I ask if KMSAN also instruments the access to the memory managed as > ZONE_DEVICE. You know this is not the RAM and also these pages will > never be onlined thus also not be available in buddy. > > Reason for the ask is that this patch is introduced because of a race > between pfn walker ends up in pfn of zone device memory. > > If KMSAN never instruments this, does it look good to you to have the > KMSAN version of pfn_valid(), as being suggested by Alexander in the > other mail. It would be nice to avoid duplicating functions - both options have downsides: 1. Shared pfn_valid(): it might break for KMSAN again in future if new recursion is introduced. 2. KMSAN-version of pfn_valid(): it might break if pfn_valid() changes in future. I suspect #1 is less likely. What is your main concern by switching to rcu_read_lock_sched()?
