Improved corrupt database detection in balance_nonroot().

FossilOrigin-Name: 5d54d9fd406381383afdf10612bfd590afc4142215d9bca09e227e3aa5baa102

manifest

@@ -1,5 +1,5 @@
-C Fix\spossible\sdivision-by-zero\sin\sthe\snew\slog()\sSQL\sfunctions.\nProblemm\sdiscovered\sby\sOSSFuzz.
-D 2021-01-29T16:20:16.527
+C Improved\scorrupt\sdatabase\sdetection\sin\sbalance_nonroot().
+D 2021-02-01T12:39:50.859
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -482,7 +482,7 @@ F src/auth.c 8d1df0e2ef8bafbedd4f1fe4baff03eb27507da4bf6e449df3613d383c4018b2
 F src/backup.c 3014889fa06e20e6adfa0d07b60097eec1f6e5b06671625f476a714d2356513d
 F src/bitvec.c 17ea48eff8ba979f1f5b04cc484c7bb2be632f33
 F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
-F src/btree.c 47d9fe97d5c0d74506154e3597f8a23b81a00080751dc4d11fec91ee22796f4c
+F src/btree.c 4da25694985ac8f5f714bfa58a6cd453f9161d7da9394a95605aaa4db2752757
 F src/btree.h 285f8377aa1353185a32bf455faafa9ff9a0d40d074d60509534d14990c7829e
 F src/btreeInt.h 7614cae30f95b6aed0c7cac7718276a55cfe2c77058cbfd8bef5b75329757331
 F src/build.c d4c06261b0e532523ede58dc511381a7a9c155132e4b65a6bb2ff76fe657793a
@@ -1046,7 +1046,7 @@ F test/fuzzdata4.db b502c7d5498261715812dd8b3c2005bad08b3a26e6489414bd13926cd3e4
 F test/fuzzdata5.db e35f64af17ec48926481cfaf3b3855e436bd40d1cfe2d59a9474cb4b748a52a5
 F test/fuzzdata6.db 92a80e4afc172c24f662a10a612d188fb272de4a9bd19e017927c95f737de6d7
 F test/fuzzdata7.db 0166b56fd7a6b9636a1d60ef0a060f86ddaecf99400a666bb6e5bbd7199ad1f2
-F test/fuzzdata8.db 7f6c5443d67ba040f760b4d28da54cc9f68174fa212ae34ccb86c645de761ec4
+F test/fuzzdata8.db 977cb95f4a5d828056dea804a6de416debe3fa0182c77f47fe19a0554aaf4db0
 F test/fuzzer1.test 3d4c4b7e547aba5e5511a2991e3e3d07166cfbb8
 F test/fuzzer2.test a85ef814ce071293bce1ad8dffa217cbbaad4c14
 F test/fuzzerfault.test 8792cd77fd5bce765b05d0c8e01b9edcf8af8536
@@ -1898,7 +1898,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 0defaf730bdc82212a5d3feeb2e16f16423b1691b0aaa7da1787eb82ea39ae9e
-R 818a051c7c4bf2ae05824d55152903eb
+P 1ffd321a33b778e87614a26a91a8407ec7b9dec4f0f847b16b1dac4f3b910604
+R b8a4f4fec4116f58162d1c62be0cf1fb
 U drh
-Z b6b8cd840ef34d4d25e074519b6e4b42
+Z 4a762bd4c15e78835f4802843c46cdfa

manifest.uuid

@@ -1 +1 @@
-1ffd321a33b778e87614a26a91a8407ec7b9dec4f0f847b16b1dac4f3b910604
+5d54d9fd406381383afdf10612bfd590afc4142215d9bca09e227e3aa5baa102

src/btree.c

@@ -7975,6 +7975,9 @@ static int balance_nonroot(
       apOld[i] = 0;
       rc = sqlite3PagerWrite(pNew->pDbPage);
       nNew++;
+      if( sqlite3PagerPageRefcount(pNew->pDbPage)!=1+(i==(iParentIdx-nxDiv)) ){
+        rc = SQLITE_CORRUPT_BKPT;
+      }
       if( rc ) goto balance_cleanup;
     }else{
       assert( i>0 );