uprobes: Flush cache after xol write

Flush the cache so that the instructions written to the XOL area are
visible.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 39c75cc51efc..5ce99cfd2e6e 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1199,6 +1199,11 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot
         vaddr = kmap_atomic(area->page);
         memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES);
         kunmap_atomic(vaddr);
+        /*
+         * We probably need flush_icache_user_range() but it needs vma.
+         * This should work on supported architectures too.
+         */
+        flush_dcache_page(area->page);
 
         return current->utask->xol_vaddr;
 }