[all-commits] [llvm/llvm-project] 0e4b21: [sanitizer_common] Don't try to unmap unaligned me...

rorth via All-commits all-commits at lists.llvm.org
Wed Feb 9 00:16:25 PST 2022

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 0e4b214b8c404d7e2f67301858ea05c209a27433
  Author: Rainer Orth <ro at gcc.gnu.org>
  Date:   2022-02-09 (Wed, 09 Feb 2022)

  Changed paths:
    M compiler-rt/lib/sanitizer_common/sanitizer_posix.cpp

  Log Message:
  [sanitizer_common] Don't try to unmap unaligned memory

Enabling `sanitizer_common` tests on Solaris (D91606
<https://reviews.llvm.org/D91606>) and SPARC (D91608
<https://reviews.llvm.org/D91608>) uncovered a sparcv9 failure

  SanitizerCommon-Unit :: ./Sanitizer-sparcv9-Test/CompactRingBuffer.int64

like this:

  [ RUN      ] CompactRingBuffer.int64
  ==24576==ERROR: SanitizerTool failed to deallocate 0x2000 (8192) bytes at address 0xffffffff7f59b000
  ==24576==Sanitizer CHECK failed: /vol/llvm/src/llvm-project/local/compiler-rt/lib/sanitizer_common/sanitizer_posix.cpp:61 (("unable to unmap" && 0)) != (0) (0, 0)

The problem is that the original allocation via
`MmapAlignedOrDieOnFatalError` is for 4 kB, but the Solaris/sparcv9
pagesize is 8 kB.  So the initial allocation is for 12 kB, rounded to a
multiple of the pagesize.  Afterwards, the unneeded rest is unmapped again,
but this fails since the address is not pagesize-aligned.

This patch avoids this by aligning the end of the mapping to the pagesize.

With D91827 <https://reviews.llvm.org/D91827> added, the test `PASS`es on

Differential Revision: https://reviews.llvm.org/D91615

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