Date: Tue, 19 Dec 2000 14:50:43 -0800 From: "Renaud Waldura" <renaud@waldura.com> To: <emulation@freebsd.org> Subject: Re: q3ded 1.17: linux_socketcall returns errno -11 Message-ID: <001f01c06a0e$1edf2200$0402010a@biohz.net> References: <01a901c067b1$8ced2d00$0402010a@biohz.net> <3A3C0199.8DED329B@cup.hp.com> <000901c067c8$d406a7e0$0402010a@biohz.net> <5l3dfmm44y.fsf@assaris.sics.se>
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Assar: thanks for the patch, it applied cleanly against 4.2-RELEASE.
As for my problem, it isn't quite solved yet... I recompiled the linux
module with DEBUG on, and here is what I get:
01 Linux-emul(90534): newselect(1, 0xbfbfb9f0, 0, 0, 0xbfbfb9e8)
02 Linux-emul(90534): incoming timeout (0/0)
03 Linux-emul(90534): real select returns 0
04 Linux-emul(90534): outgoing timeout (0/0)
05 Linux-emul(90534): newselect_out -> 0
06 Linux-emul(90534): linux_socketcall(what=12, args=0xbfbfba00)
07 Linux-emul(90534): linux_recvfrom(fd=4, buf=0x8220c40, len=16384,
flags=0, from=0xbfbfba40, fromlen=0xbfbfba3c)
08 Linux-emul(90534): linux_recvfrom() returns 35
This is how I interpret the trace:
01: newselect(number of FDs == 1
FD set ready for reading == some address
FD set ready for writing == NULL
FD set ready for OOB == NULL
timeout == some address
)
Q3ded listens an an open socket, with a timeout.
02-05: the timeout is 0: it's a poll, and select() returns with no error.
06-08: calls linux_recvfrom(), which returns EAGAIN.
Now, the funny thing is, the exact same thing happens on Linux. Here is the
strace output:
01 gettimeofday({977090705, 46700}, {420, 0}) = 0
02 select(1, [0], NULL, NULL, {0, 0}) = 0 (Timeout)
03 recvfrom(4, 0x8220c40, 16384, 0, 0xbfffba10, 0xbfffba0c) = -1 EAGAIN
(Resource temporarily unavailable)
Pretty much equivalent to the FreeBSD trace... Unfortunately q3ded on Linux
works like a charm, and it doesn't on FreeBSD. So, I'm still looking. Any
ideas?
--Renaud
----- Original Message -----
From: <assar@freebsd.org>
To: "Renaud Waldura" <renaud@waldura.com>; <marcel@freebsd.org>
Cc: <emulation@freebsd.org>
Sent: Monday, December 18, 2000 2:10 AM
Subject: Re: q3ded 1.17: linux_socketcall returns errno -11
> "Renaud Waldura" <renaud@waldura.com> writes:
>
> > 51543 q3ded CALL gettimeofday(0xbfbfba48,0xbfbfba50)
> > 51543 q3ded RET gettimeofday 0
> > 51543 q3ded CALL linux_newselect(0x1,0xbfbfb9d8,0,0,0xbfbfb9d0)
> > 51543 q3ded RET linux_newselect 0
> > 51543 q3ded CALL linux_socketcall(0xc,0xbfbfb9e8)
> > 51543 q3ded RET linux_socketcall -1 errno 11 Resource deadlock
avoided
>
> Note first that the translation of errno 11 is wrong, on Linux errno
> 11 is EAGAIN.
>
> (marcel: should we add a table of Linux error codes to linux_kdump? )
>
> So I assume that what's happening here is that select says that the fd
> is ready to be read from but then recvmsg returns EWOULDBLOCK (aka
> EAGAIN).
>
> The only way I can see that currently happening is if MSG_WAITALL for
> some reason is set, now wait a moment, MSG_* do not have the same
> values on Linux.
>
> Could you try the following patch and tell us how it goes? I'm afraid
> it's against -current. If it doesn't apply with small amounts of
> force to -stable, bug me and I can redo it. Marcel: does this look ok?
>
> /assar
>
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