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0answers
28 views

Unable to capture trace with -w option

I am not able to capture trace with the -w option on my fedora machine. Please see the log below : [root@localhost home]# tcpdump -w /home/trace.cap -i eth2 -s 0 tcpdump: listening on eth2, link-type ...
0
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2answers
74 views

Are there distros with ptrace_scope set to zero by default?

I wanted to use ptrace on a recent version of Ubuntu to inspect the memory of any other process running under the same OS user. However, I quickly stumbled upon Operation not permitted After a ...
13
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2answers
867 views

How to find out what process is writing to STDOUT?

I have two instances of a process running. One of them is "frEAkIng oUT!" and printing errors non stop to STDOUT. I want to kill the broken process but I have to make sure I don't terminate the wrong ...
3
votes
2answers
61 views

set verbose prints unrelated extra lines

Using set -x causes my shell to print unrelated stuff. For example: $ set -x ++ printf $'%157s\r' $ echo 'hello' + echo hello hello ++ printf $'%157s\r' The lines starting with '++' are extra. How ...
0
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0answers
53 views

XFS Tracing with Ftrace

I use a disk drive formatted with xfs.My OS is Ubuntu Server 12.04 LTS (kernel 3.11.0-22-generic). I would like to use ftrace (e.g.,trace-cmd record -e xfs\*) but under ...
6
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2answers
212 views

FreeBSD 10 trace disk activity

Is there any way to find some process which is periodically writing to disk (according to hdd led) on FreeBSD 10 with ZFS (maybe turn ZFS into verbose logging mode)? lsof and other instantly ...
2
votes
2answers
601 views

Why does bash add single quotes to unquoted failed pathname expansions in a command before executing it?

I was exploring the tracing of commands using set -x (set +x to unset) in bash: Print a trace of simple commands, for commands, case commands, select commands, and arithmetic for commands and ...
0
votes
1answer
74 views

How to log all udp packets from port N in readable format?

How to log into file all udp packets (in and out) from port N in readable format (capture packet type (time stamp, name of error if one happens or message type, data size, data))?
1
vote
1answer
360 views

Resolving executable user stack trace addresses in ftrace

I'm trying to obtain a user stack trace in ftrace, but for some reason, only my user program cannot resolve the addresses to symbols. First, the OS I'm using is: $ uname -a Linux mypc ...
10
votes
2answers
929 views

Observing a hard-disk write in kernel space (with drivers/modules)

Apologies in advance if this post is a bit dense/messy, but I'm having a hard time formulating it better... Basically, I would like to study what happens upon a hard disk write, and I'd like to know: ...
3
votes
2answers
2k views

Which file in kernel specifies fork(), vfork()… to use sys_clone() system call

When ltrace is used for tracing the system calls, I could see that fork() uses sys_clone() rather than sys_fork(). But I couldnt find the linux source where it is defined. My program is ...
4
votes
3answers
131 views

Can I recursively print all current remote shells?

Is there a way to print out all of the local and remote shells I am currently in, recursively? For example, on my local machine, I will ssh into another machine. From there, I may switch users ...
3
votes
1answer
242 views

How to increase ftrace precision to microseconds?

I'm trying to generate FTrace files inside an Android environment, using: root@adroid:# echo 1 > /sys/kernel/debug/tracing/events/sched/sched_switch/enable root@adroid:# echo 1 > ...
1
vote
1answer
75 views

Wrapper script to list sourced/executed files

Is it possible to write a command which runs my.sh and prints every path sourced or executed by this script recursively - That is, without altering the original code at all? The idea is to verify ...
10
votes
3answers
6k views

How to trace a java-program?

As a sysadmin I sometimes face situations, where a program behaves abnormally, while not creating errors at all or creating nonsense error-messages. In the past - before java came in - there were two ...
1
vote
1answer
133 views

Is there any way to attach latrace to an already-running process?

I want to trace a running multi-threaded process's library calls. As of 5 November 2012, there's only one way to get ltrace to fully support tracing multi-threaded processes: you must check out and ...
4
votes
2answers
3k views

What does “pollsys” mean? Solaris “truss” output

> truss -p 6482 /2: pollsys(0xE517AD88, 1, 0xE517AE30, 0x00000000) = 0 /2: pollsys(0xE517AD88, 1, 0xE517AE30, 0x00000000) = 0 /2: pollsys(0xE517AD88, 1, 0xE517AE30, 0x00000000) = 0 ...
2
votes
1answer
746 views

How to track file change

nsswitch.conf file always corrupts somehow. I do restore from my backup every time it corrupt. When this file corrupts, its time stamp is changing. Now I wonder if there is a way to track that file ? ...
2
votes
1answer
131 views

Is this task freeze related to ReiserFS (v3)? (or: is ReiserFS getting so old that it should be actively replaced?)

I just had a weird system freeze that I resolved using alt-sysrq-e. Here's my dmesg: https://gist.github.com/1609263 I was wondering whether it might be some kind of deadlock in the reiserfs3 code ...
9
votes
2answers
2k views

strace for library calls

I know of strace, which is super handy for watching system calls. Is there an equivalent that can trace calls to external libraries? For example, I'm trying to debug some SSLeay misbehavior with a ...
0
votes
1answer
3k views

How to run tcptraceroute utility on UNIX machine?

How can I run the tcptraceroute utility on a UNIX machine? I want to run a TCP traceroute for port 80.
3
votes
1answer
848 views

What does this Linux kernel trace mean?

I’m running a linux server at home which is mostly a file and e-mail server and a digital video recorder. All the data goes on an ext4 partition on a software raid-6. Every now and then (sometimes ...
1
vote
1answer
2k views

How to trace file locks (per directory)

I'm quite new to Linux and I have not really a clue on how to do this. I've got a directory and I'd like to monitor (output to shell) when a file inside that directory get's a file lock and when it ...
2
votes
1answer
133 views

Is there a way to determine which process creates a file on osx 10.6.8

I would like to know which process has created files on os X 10.6. I'm trying DTrace, which probably will give the right answer, but I have not eyes to see the method. I'm doing this because I think ...