Date: Wed, 17 Jul 2002 21:10:47 +0300 From: Tom Alsberg <alsbergt@zoopee.org> To: FreeBSD Hackers List <freebsd-hackers@freebsd.org> Subject: strace, PIOCWSTOP, NFS, and dynamically linked executables Message-ID: <20020717181047.GA24473@zoopee.org>
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Hi there...
I seem to have some problems with running strace (A program that
traces system calls, signals, and processes, in the ports:
devel/strace) on FreeBSD.
The problem is that the binary executable is not traced (it runs as a
forked process of strace, but in the background of the shell). The
only output of strace is something like:
execve("...", ["..."], [/* ... vars */]PIOCWSTOP: Resource temporarily unavailable
(What I substituted '...' for depends on the binary executed)
I couldn't find yet what this PIOCWSTOP means exactly (I didn't find
it in a search (grep) of all the /usr/include tree).
The cases when the problem happens seem to be as follows:
If I try to run strace on a statically linked binary (like most
binaries in /bin), then:
If the binary is on a remote NFS filesystem (FreeBSD 4.6 is the NFS
server in this case too, even though it seems to be so too with
NetApp's Filer servers), then first the problem happens, then after
waiting about 5 seconds and running strace on the same binary again,
the problem doesn't happen.
If the binary is on a local filesystem (UFS in this case), then the
problem does not happen.
If I try to run strace on a dynamically linked binary (like most
binaries in /usr and other installed programs), then:
If the binary is on a remote NFS filesystem, then the problem always
seems to happen.
If the binary is on a local filesystem, then the problem first
happens, and after about 5 seconds running strace on the same binary
again, the problem doesn't happen.
Or, to say:
The problem always happens with a dynamically linked binary on NFS.
The problem happens only the first time with a statically linked
binary on NFS, or a dynamically linked binary on a local filesystem.
The problem never happens with a statically linked binary on a local
filesystem.
I couldn't yet find the cause, and wonder (would be glad) if someone
could help.
Thank you, any help appreciated,
-- Tom
--
Tom Alsberg - certified insane, complete illiterate.
e-mail: <alsbergt@softhome.net>
Homepage: http://www.cs.huji.ac.il/~alsbergt/
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