Crash with memory sanitizer on Linux 6.5.0-25

[yamam]

Reproduction Steps:
The following commands reproduce with more than 50% probability.
$ echo 'int main(void) {return 0;}'|clang -fsanitize=memory -fPIE -pie -x c -;./a.out
FATAL: Code 0x62437d12e410 is out of application range. Non-PIE build?
FATAL: MemorySanitizer can not mmap the shadow memory.
FATAL: Make sure to compile with -fPIE and to link with -pie.
FATAL: Disabling ASLR is known to cause this error.
FATAL: If running under GDB, try 'set disable-randomization off'.
==10691==Process memory map follows:

Environment:
Linux PC-20240312A024 6.5.0-25-generic #25~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue Feb 20 16:09:15 UTC 2 x86_64 x86_64
x86_64 GNU/Linux
Ubuntu clang version 14.0.0-1ubuntu1.1
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

It does not occur when reverting to 6.5.0-21-generic

[DimitryAndric]

A possibly related issue is https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2056762, since this is about the Ubuntu HWE kernel, and the problem I saw was with ThreadSanitizer falling over, due to "unexpected memory mapping".

I am suspecting that Ubuntu's 6.5.0-21 -> 6.5.0-25 update changed something in the way memory mappings work (for ASLR or otherwise), that trips up some internal assertions in the sanitizers.

[DimitryAndric]

Also, google/sanitizers#1716, which seems to indicate a kernel change to be the culprit.

[yamam]

I have confirmed that it does not occur on Ubuntu 24.04.

$ clang -v
Ubuntu clang version 18.1.3 (1)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/13
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/13
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$ uname -a
Linux masanari-VirtualBox 6.8.0-31-generic #31-Ubuntu SMP PREEMPT_DYNAMIC Sat Apr 20 00:40:06 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

The following combination occurs:
Running an executable file generated on Ubuntu 22.04 (clang 14.0.0-1ubuntu1.1) on Ubuntu 24.04 (6.8.0-31-generic).

The following combination does not occur:
Running an executable file generated on Ubuntu 24.04 (clang 18.1.3 (1)) on Ubuntu 22.04 (6.5.0-28-generic).

[DimitryAndric]

I have confirmed that it does not occur on Ubuntu 24.04.
...
The following combination does not occur: Running an executable file generated on Ubuntu 24.04 (clang 18.1.3 (1)) on Ubuntu 22.04 (6.5.0-28-generic).

This is because a similar fix as for TSan got merged into llvm-project's 18.x branch:
c2a5703

I'm not sure at what version that was, but apparently 18.1.3 has it! :)

[yamam]

Thank you. Since the issue seems to have been resolved, I will close it.