Kernel function graph trace symbol lost

[kernel-cyrus]

When tracing for kernel, seeing a lot of "__compound_literal.1", seems some symbols get lost.

Command:

$ gcc -pg test.c -o test
$ sudo uftrace record -k -K 30 test
$ uftrace graph

Output:

    750.055 ms :  +-(1) main
    9.057 us :     +-(1) getpid
    7.521 us :     | (2) __compound_literal.1
    6.145 us :     | (1) __compound_literal.1
    5.025 us :     | (1) __compound_literal.1
    3.905 us :     | (1) __compound_literal.1
    2.753 us :     | (1) __compound_literal.1
    1.057 us :     | (2) __compound_literal.1
             :     | 
    1.778 ms :     +-(5) printf
    1.742 ms :     | (12) __compound_literal.1
    1.736 ms :     | (6) __compound_literal.1
    1.729 ms :     | (6) __compound_literal.1
  192.577 us :     |  +-(1) __arm64_sys_newfstatat
  156.001 us :     |  |  +-(1) vfs_statx
   97.281 us :     |  |  |  +-(1) user_path_at_empty
   40.320 us :     |  |  |  |  +-(1) getname_flags
   33.376 us :     |  |  |  |  |  +-(1) kmem_cache_alloc
   29.760 us :     |  |  |  |  |  |  +-(1) fs_reclaim_acquire
   27.200 us :     |  |  |  |  |  |  | (1) __compound_literal.1
   26.592 us :     |  |  |  |  |  |  | (1) __compound_literal.1
   25.760 us :     |  |  |  |  |  |  | (1) __compound_literal.1
   22.720 us :     |  |  |  |  |  |  | (4) __compound_literal.1
   16.704 us :     |  |  |  |  |  |  |  +-(7) __compound_literal.1
   12.640 us :     |  |  |  |  |  |  |  | (4) __compound_literal.1
   10.528 us :     |  |  |  |  |  |  |  | (2) __compound_literal.1

[honggyukim]

That's weird. It would be helpful if you could share more system info. At least, the kernel version with uname -r is needed.

[kernel-cyrus]

I finally solved this problem by disabling KGDB in the kernel config.

My platform is Nvidia AGX Orin, and the kernel is Nvidia Tegra kernel 5.15.

For some debug reason, I enabled the KGDB, and the problem finnally got solved by just disabling it.

Hope this information could help somebody else.

[honggyukim]

That's good to hear that you found the solution. Thanks for the info.

This kind of question and answer are always helpful for the later reference.