MDEV-32757: rollback crash on corruption

trx_undo_free_page(): Detect a case of corrupted TRX_UNDO_PAGE_LIST.

trx_undo_truncate_end(): Stop attempts to truncate a corrupted log.

trx_t::commit_empty(): Add an error message of a corrupted log.

Reviewed by: Thirunarayanan Balathandayuthapani

storage/innobase/trx/trx0trx.cc

@@ -976,7 +976,13 @@ void trx_t::commit_empty(mtr_t *mtr)
   trx_undo_t *&undo= rsegs.m_redo.undo;
 
   ut_ad(undo->state == TRX_UNDO_ACTIVE || undo->state == TRX_UNDO_PREPARED);
-  ut_ad(undo->size == 1);
+
+  if (UNIV_UNLIKELY(undo->size != 1))
+  {
+    sql_print_error("InnoDB: Undo log for transaction " TRX_ID_FMT
+                    " is corrupted (" UINT32PF "!=1)", id, undo->size);
+    ut_ad("corrupted undo log" == 0);
+  }
 
   if (buf_block_t *u=
       buf_page_get(page_id_t(rseg->space->id, undo->hdr_page_no), 0,

storage/innobase/trx/trx0undo.cc

@@ -740,6 +740,14 @@ trx_undo_free_page(
 		return FIL_NULL;
 	}
 
+	const fil_addr_t last_addr = flst_get_last(
+		TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST
+		+ header_block->page.frame);
+	if (UNIV_UNLIKELY(last_addr.page == page_no)) {
+		*err = DB_CORRUPTION;
+		return FIL_NULL;
+	}
+
 	*err = fseg_free_page(TRX_UNDO_SEG_HDR + TRX_UNDO_FSEG_HEADER
 			      + header_block->page.frame,
 			      rseg->space, page_no, mtr);
@@ -748,9 +756,6 @@ trx_undo_free_page(
 	}
 	buf_page_free(rseg->space, page_no, mtr);
 
-	const fil_addr_t last_addr = flst_get_last(
-		TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST
-		+ header_block->page.frame);
 	rseg->curr_size--;
 
 	if (!in_history) {
@@ -794,6 +799,9 @@ static dberr_t trx_undo_truncate_end(trx_undo_t &undo, undo_no_t limit,
 {
   ut_ad(is_temp == !undo.rseg->is_persistent());
 
+  if (UNIV_UNLIKELY(undo.last_page_no == FIL_NULL))
+    return DB_CORRUPTION;
+
   for (mtr_t mtr;;)
   {
     mtr.start();