[Bug 2048768] Re: Autopkgtest failures on amd64

[Danilo Egea Gondolfo]

** Also affects: llvm-toolchain-14 (Ubuntu Noble)
   Importance: Undecided
       Status: New

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Title:
  Autopkgtest failures on amd64

Status in llvm-toolchain-14 package in Ubuntu:
  New
Status in llvm-toolchain-14 source package in Noble:
  New

Bug description:
  Some tests related to the address sanitizer are occasionally failing
  on amd64 (also for llvm-toolchain-15 and 16):

  --------------
  FAIL: LLVM regression suite :: test_leaksan.c (38 of 45)
  746s ******************** TEST 'LLVM regression suite :: test_leaksan.c' FAILED ********************
  746s Script:
  746s --
  746s : 'RUN: at line 4';   /usr/bin/clang-14 -o /tmp/autopkgtest.gHVujV/autopkgtest_tmp/build/tests/Output/test_leaksan.c.tmp -fsanitize=address -g /tmp/autopkgtest.gHVujV/autopkgtest_tmp/tests/test_leaksan.c
  746s : 'RUN: at line 5';   env ASAN_OPTIONS="log_path=stdout:exitcode=0"  /tmp/autopkgtest.gHVujV/autopkgtest_tmp/build/tests/Output/test_leaksan.c.tmp 2>&1 > /tmp/autopkgtest.gHVujV/autopkgtest_tmp/build/tests/Output/test_leaksan.c.tmp.out
  746s : 'RUN: at line 6';   grep -q "detected memory leaks" /tmp/autopkgtest.gHVujV/autopkgtest_tmp/build/tests/Output/test_leaksan.c.tmp.out
  746s --
  746s Exit Code: 139
  746s
  746s Command Output (stderr):
  746s --
  746s /tmp/autopkgtest.gHVujV/autopkgtest_tmp/build/tests/Output/test_leaksan.c.script: line 3:  3335 Segmentation fault      (core dumped) env ASAN_OPTIONS="log_path=stdout:exitcode=0" /tmp/autopkgtest.gHVujV/autopkgtest_tmp/build/tests/Output/test_leaksan.c.tmp 2>&1 > /tmp/autopkgtest.gHVujV/autopkgtest_tmp/build/tests/Output/test_leaksan.c.tmp.out
  --------------

  If you run the test manually you'll notice that it works but
  eventually crashes:

  --------------------
  ubuntu at autopkgtest:/tmp/autopkgtest.oXC2FP/autopkgtest_tmp/build/tests/Output$ ./test_leaksan.c.tmp

  =================================================================
  ==8631==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 7 byte(s) in 1 object(s) allocated from:
      #0 0x5e9c3441ed12 in __interceptor_malloc (/tmp/autopkgtest.oXC2FP/autopkgtest_tmp/build/tests/Output/test_leaksan.c.tmp+0xa3d12) (BuildId: 6f71ac388125722ade1ea86ee3661c0d884dd193)
      #1 0x5e9c3445acb8 in main /tmp/autopkgtest.oXC2FP/autopkgtest_tmp/tests/test_leaksan.c:13:7
      #2 0x7e84e1e280cf  (/lib/x86_64-linux-gnu/libc.so.6+0x280cf) (BuildId: f0b834daa3d05a80967e9ec2f990a1ea71c958fa)

  SUMMARY: AddressSanitizer: 7 byte(s) leaked in 1 allocation(s).
  ubuntu at autopkgtest:/tmp/autopkgtest.oXC2FP/autopkgtest_tmp/build/tests/Output$ ./test_leaksan.c.tmp

  =================================================================
  ==8634==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 7 byte(s) in 1 object(s) allocated from:
      #0 0x5f19be5f6d12 in __interceptor_malloc (/tmp/autopkgtest.oXC2FP/autopkgtest_tmp/build/tests/Output/test_leaksan.c.tmp+0xa3d12) (BuildId: 6f71ac388125722ade1ea86ee3661c0d884dd193)
      #1 0x5f19be632cb8 in main /tmp/autopkgtest.oXC2FP/autopkgtest_tmp/tests/test_leaksan.c:13:7
      #2 0x77c7d3c280cf  (/lib/x86_64-linux-gnu/libc.so.6+0x280cf) (BuildId: f0b834daa3d05a80967e9ec2f990a1ea71c958fa)

  SUMMARY: AddressSanitizer: 7 byte(s) leaked in 1 allocation(s).

  ubuntu at autopkgtest:/tmp/autopkgtest.oXC2FP/autopkgtest_tmp/build/tests/Output$ ./test_leaksan.c.tmp
  Segmentation fault (core dumped)
  --------------------

  After some investigation I found that it will not fail with ASLR
  disabled:

  sudo sysctl kernel.randomize_va_space=0

  while : ; do env ASAN_OPTIONS="log_path=stdout:exitcode=0"
  ./test_leaksan.c.tmp >/dev/null; if [ $? -ne 0 ] ; then echo crashed ;
  fi done

  If you enable ASLR it will start to crash:

  $ sudo sysctl kernel.randomize_va_space=2

  $ while : ; do env ASAN_OPTIONS="log_path=stdout:exitcode=0" ./test_leaksan.c.tmp >/dev/null; if [ $? -ne 0 ] ; then echo crashed ; fi done
  Segmentation fault (core dumped)
  crashed
  Segmentation fault (core dumped)
  crashed
  Segmentation fault (core dumped)
  crashed
  Segmentation fault (core dumped)
  crashed
  Segmentation fault (core dumped)
  crashed

  If you and ASLR again and run it with "setarch -R" (to disable ASLR
  for this binary), it will also not crash.

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