From dea6570fc192814a06ae9d6bd4f1501e5cab3bc9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=9B=D0=B5=D0=BE=D0=BD=D0=B8=D0=B4=20=D0=AE=D1=80=D1=8C?=
 =?UTF-8?q?=D0=B5=D0=B2=20=28Leonid=20Yuriev=29?= <leo@yuriev.ru>
Date: Fri, 10 Nov 2023 13:48:06 +0300
Subject: [PATCH] =?UTF-8?q?mdbx:=20=D0=B4=D0=BE=D1=80=D0=B0=D0=B1=D0=BE?=
 =?UTF-8?q?=D1=82=D0=BA=D0=B0=20`coherency=5Fcheck()`=20=D0=B4=D0=BB=D1=8F?=
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---
 src/core.c | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/core.c b/src/core.c
index e94f4eba..6d62234e 100644
--- a/src/core.c
+++ b/src/core.c
@@ -8939,20 +8939,45 @@ static bool coherency_check(const MDBX_env *env, const txnid_t txnid,
                             const volatile MDBX_meta *meta, bool report) {
   const txnid_t freedb_mod_txnid = dbs[FREE_DBI].md_mod_txnid;
   const txnid_t maindb_mod_txnid = dbs[MAIN_DBI].md_mod_txnid;
+  const pgno_t last_pgno = meta->mm_geo.now;
 
   const pgno_t freedb_root_pgno = dbs[FREE_DBI].md_root;
-  const MDBX_page *freedb_root = (env->me_map && freedb_root_pgno != P_INVALID)
+  const MDBX_page *freedb_root = (env->me_map && freedb_root_pgno < last_pgno)
                                      ? pgno2page(env, freedb_root_pgno)
                                      : nullptr;
 
   const pgno_t maindb_root_pgno = dbs[MAIN_DBI].md_root;
-  const MDBX_page *maindb_root = (env->me_map && maindb_root_pgno != P_INVALID)
+  const MDBX_page *maindb_root = (env->me_map && maindb_root_pgno < last_pgno)
                                      ? pgno2page(env, maindb_root_pgno)
                                      : nullptr;
   const uint64_t magic_and_version =
       unaligned_peek_u64_volatile(4, &meta->mm_magic_and_version);
 
   bool ok = true;
+  if (freedb_root_pgno != P_INVALID &&
+      unlikely(freedb_root_pgno >= last_pgno)) {
+    if (report)
+      WARNING(
+          "catch invalid %sdb root %" PRIaPGNO " for meta_txnid %" PRIaTXN
+          " %s",
+          "free", freedb_root_pgno, txnid,
+          (env->me_stuck_meta < 0)
+              ? "(workaround for incoherent flaw of unified page/buffer cache)"
+              : "(wagering meta)");
+    ok = false;
+  }
+  if (maindb_root_pgno != P_INVALID &&
+      unlikely(maindb_root_pgno >= last_pgno)) {
+    if (report)
+      WARNING(
+          "catch invalid %sdb root %" PRIaPGNO " for meta_txnid %" PRIaTXN
+          " %s",
+          "main", maindb_root_pgno, txnid,
+          (env->me_stuck_meta < 0)
+              ? "(workaround for incoherent flaw of unified page/buffer cache)"
+              : "(wagering meta)");
+    ok = false;
+  }
   if (unlikely(txnid < freedb_mod_txnid ||
                (!freedb_mod_txnid && freedb_root &&
                 likely(magic_and_version == MDBX_DATA_MAGIC)))) {