Bug #18409: Crash (free(): invalid pointer) if LD_PRELOAD doesn't explicitly include libjemalloc.so.2

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 3.0.3p157 (2021-11-24 revision 3fb7d2cadc) [x86_64-linux]
• Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: DONE

[itay-grudev (Itay Grudev)]

I recently installed Ruby 3.0.2 using rbenv with:

RUBY_CONFIGURE_OPTS='--with-jemalloc' rbenv install 3.0.2

After running our app it always crashed with:

free(): invalid pointer
[1]    51364 IOT instruction (core dumped)  bundle exec rails assets:precompile

I also tried upgrading to 3.0.3 with no success.

After researching the bug a lot and lots of failed attempt to track it down I stumbled upon this report: https://github.com/grpc/grpc/issues/25450 that recommended trying:

LD_PRELOAD=$LD_PRELOAD:/lib/x86_64-linux-gnu/libjemalloc.so.2 bundle exec rails assets:precompile

That seems to have worked, but that can't be the proper solution in production. Surely it shouldn't be required.

[xtkoba (Tee KOBAYASHI)]

Seems like someone (who?) is calling libc free() directly, maybe?

[itay-grudev (Itay Grudev)]

How can I try to trace it? I tried attaching GDB to the process with little success.

[xtkoba (Tee KOBAYASHI)]

I noticed that 737e4432b978eb4b9f5b10fb6cc6d9c883a5d17a is not backported to Ruby 3.0.x series. So before ./configure you may need to do something like

export LDFLAGS="-Wl,--no-as-needed"

Make sure that the ruby executable has DT_NEEDED entry for libjemalloc.so:

$ readelf -Wa ruby | grep NEEDED
 0x0000000000000001 (NEEDED)             Shared library: [libruby.so.3.1]
 0x0000000000000001 (NEEDED)             Shared library: [libz.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libpthread.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [librt.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libjemalloc.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libgmp.so.10]
 0x0000000000000001 (NEEDED)             Shared library: [libdl.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libcrypt.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libm.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libbacktrace.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Closed
• Backport changed from 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN to 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: REQUIRED

Since it looks like this is fixed in the master branch, closing and marking for backport to Ruby 3.0 (not sure if it is needed on Ruby 2.7).

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: REQUIRED to 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: DONE

ruby_3_0 09b27ec6a984ec1b660d5b7b48f2ff4d5a0065bc merged revision(s) 737e4432b978eb4b9f5b10fb6cc6d9c883a5d17a.

[eviljoel (evil joel)]

I requested a 2.7 back port here: https://bugs.ruby-lang.org/issues/18650