From 17c05f18e54158a3eed0c22c85b7a756b63dcc01 Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Mon, 27 Feb 2023 09:36:25 -0800 Subject: [PATCH] mm: prevent do_swap_page from handling page faults under VMA lock Due to the possibility of do_swap_page dropping mmap_lock, abort fault handling under VMA lock and retry holding mmap_lock. This can be handled more gracefully in the future. Link: https://lkml.kernel.org/r/20230227173632.3292573-27-surenb@google.com Signed-off-by: Suren Baghdasaryan Reviewed-by: Laurent Dufour Signed-off-by: Andrew Morton --- mm/memory.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index 10d497a..70f4b12 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3697,6 +3697,11 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) if (!pte_unmap_same(vmf)) goto out; + if (vmf->flags & FAULT_FLAG_VMA_LOCK) { + ret = VM_FAULT_RETRY; + goto out; + } + entry = pte_to_swp_entry(vmf->orig_pte); if (unlikely(non_swap_entry(entry))) { if (is_migration_entry(entry)) { -- 2.7.4