[compiler-rt] [scudo] Fix the logic of MaxAllowedFragmentedPages (PR #107927)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `sanitizer-x86_64-linux-qemu` running on `sanitizer-buildbot3` while building `compiler-rt` at step 2 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/139/builds/3565

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 2 (annotate) failure: 'python ../sanitizer_buildbot/sanitizers/zorg/buildbot/builders/sanitizers/buildbot_selector.py' (failure)
...
[71/77] Generating ScudoUnitTestsObjects.primary_test.cpp.aarch64.o
[72/77] Generating ScudoUnitTestsObjects.gtest-all.cc.aarch64.o
[73/77] Generating ScudoCxxUnitTest-aarch64-Test
[74/77] Generating ScudoCUnitTest-aarch64-Test
[75/77] Generating ScudoUnitTestsObjects.combined_test.cpp.aarch64.o
[76/77] Generating ScudoUnitTest-aarch64-Test
[76/77] Running Scudo Standalone tests
llvm-lit: /home/b/sanitizer-x86_64-linux-qemu/build/llvm-project/llvm/utils/lit/lit/main.py:72: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 900 seconds was requested on the command line. Forcing timeout to be 900 seconds.
-- Testing: 314 tests, 88 workers --
Testing: 
FAIL: ScudoStandalone-Unit :: ./ScudoCxxUnitTest-aarch64-Test/2/3 (1 of 314)
******************** TEST 'ScudoStandalone-Unit :: ./ScudoCxxUnitTest-aarch64-Test/2/3' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoCxxUnitTest-aarch64-Test-ScudoStandalone-Unit-2791140-2-3.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=3 GTEST_SHARD_INDEX=2 /home/b/sanitizer-x86_64-linux-qemu/build/qemu_build/qemu-aarch64 -L /usr/aarch64-linux-gnu /home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoCxxUnitTest-aarch64-Test
--

Note: This is test shard 3 of 3.
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from ScudoWrappersCppTest
[ RUN      ] ScudoWrappersCppTest.AllocAfterFork
Scudo ERROR: CHECK failed @ /home/b/sanitizer-x86_64-linux-qemu/build/llvm-project/compiler-rt/lib/scudo/standalone/secondary.h:737 (CachedBlock::MaxReleasedCachePages) == (0U) ((u64)op1=4, (u64)op2=0)
qemu: uncaught target signal 6 (Aborted) - core dumped

--
exit: -6
--
shard JSON output does not exist: /home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoCxxUnitTest-aarch64-Test-ScudoStandalone-Unit-2791140-2-3.json
********************
Testing:  0
FAIL: ScudoStandalone-Unit :: ./ScudoUnitTest-aarch64-Test/104/139 (15 of 314)
******************** TEST 'ScudoStandalone-Unit :: ./ScudoUnitTest-aarch64-Test/104/139' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoUnitTest-aarch64-Test-ScudoStandalone-Unit-2791140-104-139.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=139 GTEST_SHARD_INDEX=104 /home/b/sanitizer-x86_64-linux-qemu/build/qemu_build/qemu-aarch64 -L /usr/aarch64-linux-gnu /home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoUnitTest-aarch64-Test
--

Note: This is test shard 105 of 139.
[==========] Running 2 tests from 2 test suites.
[----------] Global test environment set-up.
[----------] 1 test from ScudoCombinedTestReallocateLargeDecreasing_DefaultConfig
[ RUN      ] ScudoCombinedTestReallocateLargeDecreasing_DefaultConfig.ReallocateLargeDecreasing
Scudo ERROR: CHECK failed @ /home/b/sanitizer-x86_64-linux-qemu/build/llvm-project/compiler-rt/lib/scudo/standalone/secondary.h:737 (CachedBlock::MaxReleasedCachePages) == (0U) ((u64)op1=4, (u64)op2=0)
qemu: uncaught target signal 6 (Aborted) - core dumped

--
exit: -6
--
Step 22 (scudo debug_aarch64_qemu) failure: scudo debug_aarch64_qemu (failure)
...
[71/77] Generating ScudoUnitTestsObjects.primary_test.cpp.aarch64.o
[72/77] Generating ScudoUnitTestsObjects.gtest-all.cc.aarch64.o
[73/77] Generating ScudoCxxUnitTest-aarch64-Test
[74/77] Generating ScudoCUnitTest-aarch64-Test
[75/77] Generating ScudoUnitTestsObjects.combined_test.cpp.aarch64.o
[76/77] Generating ScudoUnitTest-aarch64-Test
[76/77] Running Scudo Standalone tests
llvm-lit: /home/b/sanitizer-x86_64-linux-qemu/build/llvm-project/llvm/utils/lit/lit/main.py:72: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 900 seconds was requested on the command line. Forcing timeout to be 900 seconds.
-- Testing: 314 tests, 88 workers --
Testing: 
FAIL: ScudoStandalone-Unit :: ./ScudoCxxUnitTest-aarch64-Test/2/3 (1 of 314)
******************** TEST 'ScudoStandalone-Unit :: ./ScudoCxxUnitTest-aarch64-Test/2/3' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoCxxUnitTest-aarch64-Test-ScudoStandalone-Unit-2791140-2-3.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=3 GTEST_SHARD_INDEX=2 /home/b/sanitizer-x86_64-linux-qemu/build/qemu_build/qemu-aarch64 -L /usr/aarch64-linux-gnu /home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoCxxUnitTest-aarch64-Test
--

Note: This is test shard 3 of 3.
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from ScudoWrappersCppTest
[ RUN      ] ScudoWrappersCppTest.AllocAfterFork
Scudo ERROR: CHECK failed @ /home/b/sanitizer-x86_64-linux-qemu/build/llvm-project/compiler-rt/lib/scudo/standalone/secondary.h:737 (CachedBlock::MaxReleasedCachePages) == (0U) ((u64)op1=4, (u64)op2=0)
qemu: uncaught target signal 6 (Aborted) - core dumped

--
exit: -6
--
shard JSON output does not exist: /home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoCxxUnitTest-aarch64-Test-ScudoStandalone-Unit-2791140-2-3.json
********************
Testing:  0
FAIL: ScudoStandalone-Unit :: ./ScudoUnitTest-aarch64-Test/104/139 (15 of 314)
******************** TEST 'ScudoStandalone-Unit :: ./ScudoUnitTest-aarch64-Test/104/139' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoUnitTest-aarch64-Test-ScudoStandalone-Unit-2791140-104-139.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=139 GTEST_SHARD_INDEX=104 /home/b/sanitizer-x86_64-linux-qemu/build/qemu_build/qemu-aarch64 -L /usr/aarch64-linux-gnu /home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_debug_aarch64_qemu/lib/scudo/standalone/tests/./ScudoUnitTest-aarch64-Test
--

Note: This is test shard 105 of 139.
[==========] Running 2 tests from 2 test suites.
[----------] Global test environment set-up.
[----------] 1 test from ScudoCombinedTestReallocateLargeDecreasing_DefaultConfig
[ RUN      ] ScudoCombinedTestReallocateLargeDecreasing_DefaultConfig.ReallocateLargeDecreasing
Scudo ERROR: CHECK failed @ /home/b/sanitizer-x86_64-linux-qemu/build/llvm-project/compiler-rt/lib/scudo/standalone/secondary.h:737 (CachedBlock::MaxReleasedCachePages) == (0U) ((u64)op1=4, (u64)op2=0)
qemu: uncaught target signal 6 (Aborted) - core dumped

--
exit: -6
--

```

</details>

https://github.com/llvm/llvm-project/pull/107927