I'm seeing the in_atomic() check in page_cache_get_speculative() (linux/pagemap.h:138) fail when running e500 KVM with . It's coming from get_user_pages_fast(), from KVM's hva_to_pfn(). This is on kvm.git plus a few local patches that should be completely unrelated, but it looks like this code hasn't changed much in a couple years.
Interrupts are disabled by get_user_pages_fast(), but apparently preemption was not separately disabled. The comment in page_cache_get_speculative() says that preemption disabling is done by rcu_read_lock(), and that "this function must be called inside the same rcu_read_lock() section as has been used to lookup the page in the pagecache radix-tree (or page table)". Where is this RCU lock supposed to be acquired? I don't see any RCU in arch/powerpc/mm/gup.c. Is it buried in some macro or function call? -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
