[question] emtpy result when read core file

[kevalin]

I use docker container to run Node.js apps. Sometimes, I got many core files, like this core.33067 that It is about 650M size. So I copy the core files to my pc DebianOS, has same node version v14.16.0.

root@bullseye:/vagrant_data/core-files# llnode node -c core.30066
(lldb) target create "node" --core "core.30066"
Core file '/vagrant_data/core-files/core.30066' (x86_64) was loaded.

(lldb) plugin load '/usr/local/share/.config/yarn/global/node_modules/llnode/llnode.so'
(lldb) settings set prompt '(llnode) '
(llnode) v8 bt
[llnode][LoadConstant ../src/constants.cc:88] Failed to load constant frametype_JavaScriptFrame, default to -1
[llnode][DoExecute ../src/llnode.cc:82] Failed to load pointer from v8 memory
 * thread #1: tid = 30066, 0x00007f44e26619f3, name = 'node', stop reason = signal SIGABRT
  * frame #0: 0x00007f44e26619f3
(llnode) exit

I don't know anyone step is wrong. Do I use same os env to read core file? I don't know. Could u help me? Thanks.

[No9]

Hi @Kevalin It seems like you are debugging a crashed docker process rather than the node.js process. Can you confirm how you are running the docker container to obtain the node.js core dump?

I would expect to see something like the following. Note the explicit volume mount so that the guest container can save to shared storage: e.g. docker run --ulimit core=-1 --mount source=coredumps_volume,target=/cores ab3ca583c907 ./node command

And how the the host kernel.core_pattern is configured. e.g. On the docker host run sysctl -n kernel.core_pattern

[kevalin]

Hi @Kevalin It seems like you are debugging a crashed docker process rather than the node.js process. Can you confirm how you are running the docker container to obtain the node.js core dump?

I would expect to see something like the following. Note the explicit volume mount so that the guest container can save to shared storage: e.g. docker run --ulimit core=-1 --mount source=coredumps_volume,target=/cores ab3ca583c907 ./node command

And how the the host kernel.core_pattern is configured. e.g. On the docker host run sysctl -n kernel.core_pattern

Hello @No9

This is my docker host config

[root@xxx-0001 ~]# sysctl -n kernel.core_pattern
core
[root@xxx-0001 ~]# ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 63455
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 65535
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 63455
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

---

login in docker container

/app # sysctl -a | grep core
kernel.core_pattern = core
kernel.core_pipe_limit = 0
kernel.core_uses_pid = 1

App directory of docker container has mounted to host volume, so I can read core file on my host.