Re: RFD: Non-Disruptive Core Dump Infrastructure

[KOSAKI Motohiro <kosaki.motohiro@gmail.com>]

(9/3/13 4:39 AM), Janani Venkataraman wrote:
> Hello,
>
> We are working on an infrastructure to create a system core file of a specific
> process at run-time, non-disruptively. It can also be extended to a case where
> a process is able to take a self-core dump.
>
> gcore, an existing utility creates a core image of the specified process. It
> attaches to the process using gdb and runs the gdb gcore command and then
> detaches. In gcore the dump cannot be issued from a signal handler context as
> fork() is not signal safe and moreover it is disruptive in nature as the gdb
> attaches using ptrace which sends a SIGSTOP signal. Hence the gcore method
> cannot be used if the process wants to initiate a self dump.

Maybe I'm missing something. But why gcore uses c-level fork()? gcore need to
call pthread-at-fork handler? No. gcore need to flush stdio buffer? No.