mm/memory.c:zap_pte_range() print bad swap entry

We have a report of this WARN() triggering.  Let's print the offending
swp_entry_t to help diagnosis.

Link: https://lkml.kernel.org/r/000000000000b0e576060a30ee3b@google.com
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index 1f18ed4a54971dd8737e7fb108d093bc702d777c..5c757fba8858a592281ea9ad479feee15314e46b 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1517,6 +1517,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
                                continue;
                } else {
                        /* We should have covered all the swap entry types */
+                       pr_alert("unrecognized swap entry 0x%lx\n", entry.val);
                        WARN_ON_ONCE(1);
                }
                pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);