select fails on windows because a non-socket fd is in the rfds set

[Arie]

The select call in file main_loop.c at line 460 fails on windows because a non-socket fd is in the rfds set. As a result, gdb remote connections will never be accepted by qemu. The select function returns with -1. WSAGetLastError returns code 10038 (WSAENOTSOCK).

I start qemu as follows:
qemu-system-arm -cpu cortex-m3 -M lm3s6965evb -nographic -monitor null -serial null -semihosting -kernel test1.elf -S -gdb tcp:127.0.0.1:2200

qemu is configure with:
CFLAGS="-O4 -march=i686"
configure --target-list="i386-softmmu arm-softmmu sparc-softmmu ppc-softmmu" --prefix=/home/qemu/install --cc=mingw32-gcc --host-cc=mingw32-gcc --audio-drv-list="dsound sdl" --audio-card-list="ac97 es1370 sb16 cs4231a adlib gus"

[Paolo Bonzini (bonzini)]

Do you know where the non-socket fd comes from? I have some patches to improve the situation on Win32 for the main loop, I'll send them next week to the mailing list.

[Arie (arie-7)]

It is added to the list by glib_select_fill. Other than that I couldn't find out what the fd is for.

I forgot to add the symptoms of the problem, so i'll add them now so people can google them.
target remote tcp:127.0.0.1:2200
Ignoring packet error, continuing...
warning: unrecognized item "timeout" in "qSupported" response
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Malformed response to offset query, timeout

[tombo (tbo-t)]

I'm also getting this error. Both on my own compile version 1.0 and on the version from http://lassauge.free.fr/qemu/
I have not been able to find a workaround for getting gdb to work. Does anybody knows a patch or a workaround?

[Michael Rolnik (mrolnik)]

it seems that g_main_context_default creates a semaphore which is added into rfds passed to glib_select_fill function, that's why select fails.

[Paolo Bonzini (bonzini)]

Patches posted to the list.

http://permalink.gmane.org/gmane.comp.emulators.qemu/142634

[Meador Inge (meadori)]

I am still seeing the symptoms that Arie pointed out:

Remote debugging using :1234
Ignoring packet error, continuing...
warning: unrecognized item "timeout" in "qSupported" response
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Malformed response to offset query, timeout

I started QEMU like:

arm-none-eabi-qemu-system.exe -gdb tcp:127.0.0.1:1234,nowait,nodelay,server,ipv4 -S -semihosting -kernel hello.out

This was with an ARM EABI system emulator that I built from today's mainline. From a brief look it seems like QEMU is going into 'g_poll' and never coming out.

[Thomas Huth (th-huth)]

Triaging old bug tickets... can you still reproduce this issue with the latest version of QEMU? Or could we close this ticket nowadays?

[Launchpad Janitor (janitor)]

[Expired for QEMU because there has been no activity for 60 days.]