node v16.13: infinite loop in node_mksnapshot

[andreas-schwab]

While building node v16.13 (using v8 9.4.146.19) the following command runs into an infinite loop:

LD_LIBRARY_PATH=/home/abuild/rpmbuild/BUILD/node-v16.13.0/out/Release/lib.host:/home/abuild/rpmbuild/BUILD/node-v16.13.0/out/Release/lib.target:$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; cd ../.; mkdir -p /home/abuild/rpmbuild/BUILD/node-v16.13.0/out/Release/obj/gen; "/home/abuild/rpmbuild/BUILD/node-v16.13.0/out/Release/node_mksnapshot" "/home/abuild/rpmbuild/BUILD/node-v16.13.0/out/Release/obj/gen/node_snapshot.cc"

https://build.opensuse.org/package/live_build_log/openSUSE:Factory:RISCV/nodejs16/standard/riscv64

[luyahan]

I run

osc -A https://api.opensuse.org checkout openSUSE:Factory:RISCV/nodejs16 && cd $_ 
osc build standard riscv64

encounter error:

/usr/sbin/zic: /lib64/lp64d/libc.so.6: version `GLIBC_2.34' not found (required by /usr/sbin/zic)

[andreas-schwab]

Did you reuse an old build root? Try adding --clean.

[luyahan]

Did you reuse an old build root? Try adding --clean.

Thanks

And when i want to debug it by gdb
But gdb return error:

(gdb) run --riscv-debug ./node_snapshot.cc
Starting program: /home/abuild/rpmbuild/BUILD/node-v16.13.0/out/Release/node_mksnapshot --riscv-debug ./node_snapshot.cc
warning: Could not trace the inferior process.
warning: ptrace: Function not implemented
During startup program exited with code 127.

Is this virtual machine don't support gdb?

[lazyparser]

Looks like it is caused by nested VM. gdb uses ptrace for sub-process operations. ptrace is a feature of kernel IIRC.

https://stackoverflow.com/a/68439156

[andreas-schwab]

Qemu linux-user emulation does not support ptrace. You need to use system emulation or real hardware if you want to run gdb. I usually export the build root via nfs, so that I can mount it on my hifive board. Or you can use "osc build --vm-type qemu native riscv64" to start qemu in system emulation.

[luyahan]

Qemu linux-user emulation does not support ptrace. You need to use system emulation or real hardware if you want to run gdb. I usually export the build root via nfs, so that I can mount it on my hifive board. Or you can use "osc build --vm-type qemu native riscv64" to start qemu in system emulation.

Hi @andreas-schwab
In builtins-riscv64.cc:3704

__ Branch(&install_baseline_code, eq, type, Operand(FEEDBACK_VECTOR_TYPE));

It should be ne not eq

[luyahan]

Qemu linux-user emulation does not support ptrace. You need to use system emulation or real hardware if you want to run gdb. I usually export the build root via nfs, so that I can mount it on my hifive board. Or you can use "osc build --vm-type qemu native riscv64" to start qemu in system emulation.

Hi @andreas-schwab In builtins-riscv64.cc:3704

__ Branch(&install_baseline_code, eq, type, Operand(FEEDBACK_VECTOR_TYPE));

It should be ne not eq

May be you should add patch : https://chromium-review.googlesource.com/c/v8/v8/+/3093009

[andreas-schwab]

Importing the whole patch causes node_mksnapshot to crash.

[andreas-schwab]

And the s/eq/ne/ change alone has the same problem.

[luyahan]

Importing the whole patch causes node_mksnapshot to crash.

i will try it again

[luyahan]

0001-fix.zip
HI @andreas-schwab ~
Try this. It should fix this.

[lazyparser]

0001-fix.zip HI @andreas-schwab ~ Try this. It should fix this.

Paste the patch as a github gist may better.

Thanks. I had updated.

[andreas-schwab]

Thanks a lot, this patch fixes the issue.

[luyahan]

patch:
https://chromium-review.googlesource.com/c/v8/v8/+/3093009
https://chromium-review.googlesource.com/c/v8/v8/+/3096886