Re: [PATCH] Guard against killing unrelated processes in amd64-disp-step.exp

[Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>]

Hi Tom,

>>>>>> "Rainer" == Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE> writes:
>
> Rainer> When testing current gdb trunk on Solaris/amd64, the whole session was
> Rainer> reliably terminated by make check.  I could trace this to the following
> Rainer> entry in gdb.arch/amd64-disp-step/gdb.log:
>
> Thank you for the patch.
>
> Rainer> If $inferior_pid doesn't refer a single process for some reason, this
> Rainer> kill would terminate either a process group or the whole session.
>
> I don't mind the patch, it seems like an improvement -- but I wonder why

That's what I thought: if for whatever reason the pid turns
non-positive, hell breaks lose if that's passed to kill unchecked.

> this ends up as -1, and whether a fix belongs elsewhere.

gdb.log shows

(gdb) PASS: gdb.arch/amd64-disp-step.exp: add into rcx: send_signal=off: verify_regs: rdi expected value
jump test_rip_rcx
Continuing at 0x4015b2.

Program terminated with signal SIGALRM, Alarm clock.
The program no longer exists.
[...]
[Current inferior is 1 [<null>] (/vol/obj/gnu/gdb/gdb/11.4-amd64-dist/gdb/testsuite/outputs/gdb.arch/amd64-disp-step/amd64-disp-step)]

lib/gdb.exp (get_inferior_pid) turns this <null> into -1:

proc get_inferior_pid {} {
    set pid -1
    gdb_test_multiple "inferior" "get inferior pid" {
        -re "process (\[0-9\]*).*$::gdb_prompt $" {
            set pid $expect_out(1,string)
            pass $gdb_test_name
        }
    }
    return $pid
}

This is certainly something that shouldn't happen and fixing the
underlying problem(s) would avoid the kill for sure.  However, the
Solaris gdb port is in a terrible state with about 3200 testsuite
failures on amd64-pc-solaris2.11.  I've made a few attempts to fix the
most glaring issues, but that never got me anywere until I've decided
that the gdb codebase is simply beyond my abilities.

	Rainer

-- 
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Rainer Orth, Center for Biotechnology, Bielefeld University