Dan Bongert wrote:
Dan Bongert wrote:
Filipe Brandenburger wrote:
Hi,
On Tue, Mar 25, 2008 at 2:21 PM, Dan Bongert dbongert@wisc.edu wrote:
thoth(3) /tmp> ls
thoth(4) /tmp> echo $? 141
141 is SIGPIPE. If the process is killed by a signal, the return code will be 128+signal number. 141-128=13, and kill -l says: 13) SIGPIPE.
SIGPIPE means that something that ls is writing to is being closed. That's really strange, and I couldn't find why.
I still think strace would be the best way to trace it. Please try:
# rm -f /tmp/ls-strace.txt; strace -o /tmp/ls-strace.txt -tt -s 1024 -f ls --color=tty
Repeat it until ls doesn't print anything. Then less your /tmp/ls-strace.txt file, you'll probably have something like +++ killed by SIGPIPE +++ as the last line of it. Then try to figure out what happened before it got the SIGPIPE. Probably a "write" to something, try to figure out to which file descriptor. If you can't do it, try to post the last few lines of the file here.
I tried it, but as I said before, strace somehow interferes with what's going on. I wasn't able to get a program to fail via strace.
Also, can you post the output of this command? # ls -la /proc/$$/fd/
thoth(265) /tmp> ls -la /proc/$$/fd/
thoth(266) /tmp> ls -la /proc/$$/fd/ total 5 dr-x------ 2 dbongert dbongert 0 Mar 27 10:17 . dr-xr-xr-x 3 dbongert dbongert 0 Mar 27 10:03 .. lrwx------ 1 dbongert dbongert 64 Mar 27 10:17 0 -> /dev/pts/0 lrwx------ 1 dbongert dbongert 64 Mar 27 10:17 1 -> /dev/pts/0 lrwx------ 1 dbongert dbongert 64 Mar 27 10:17 2 -> /dev/pts/0 lrwx------ 1 dbongert dbongert 64 Mar 27 10:17 255 -> /dev/pts/0 lrwx------ 1 dbongert dbongert 64 Mar 27 10:17 3 -> socket:[4425494]
Ok, here I am replying to myself. On a lark, I tried to strace a different program, since I couldn't get strace + ls to fail. Here's the end of the output from 'strace w':
connect(4, {sa_family=AF_FILE, path="/var/run/nscd/socket"}, 110) = 0 poll([{fd=4, events=POLLOUT|POLLERR|POLLHUP, revents=POLLOUT|POLLHUP}], 1, 5000) = 1 writev(4, [{"\2\0\0\0\1\0\0\0\2\0\0\0", 12}, {"0\0", 2}], 2) = -1 EPIPE (Broken pipe) --- SIGPIPE (Broken pipe) @ 0 (0) --- +++ killed by SIGPIPE +++
Looks like a nscd problem, and disabling it seems to fix the problem.
Good stuff, actually the nscd problem may even be a symptom to an nsswitch problem. Check to make sure you don't have a name service enabled in /etc/nsswitch that isn't actually working.
-Ross
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