cannot see pthread_cond_wait on offcpu graph about bcc HOT 5 OPEN

The issue I mentioned is only related in case of stripped library. Sorry for confusion.

The problem you are suffering is related to stack backtracing failure. In other words, this issue happened because kernel don't know how to interpret the stack.

To resolve this issue, you should build libc.so with -fno-omit-frame-poiner.
Please check the similar issue here #4735

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I do this with mysqld, and get same result. The function above the thread name is __futex_abstimed_wait_common. Obviously the thread never calls it directly.

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Can you show me the result of the file command output of libc.so file?
I'm pretty sure this issue can be happened because of this issue #4849 , if it is stripped.

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@Bojun-Seo

Here's the result:

# file /lib64/libc.so.6
/lib64/libc.so.6: ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=81daba31ee66dbd63efdc4252a872949d874d136, for GNU/Linux 3.2.0, not stripped

# readelf -S /lib64/libc.so.6 | grep debug
  [66] .gnu_debuglink    PROGBITS         0000000000000000  001d6140

Not stripped, but no debug info.

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Or you can apply these PRs to unwind stack without kernel's help. #4463 #4679

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