The Return of the Frame Pointers
Brendan Gregg
MARCH 16, 2024
It finally gets through the kernel frames then steps through the syscall (sys_write()) to userspace, hits the libc syscall wrapper (__GI libc_write()), then tries to resolve the symbol for the next frame but fails and records "[unknown]". This is pretty common and usually goes unnoticed as the flame graph looks ok at first glance.
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