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84 lines
1.9 KiB
84 lines
1.9 KiB
.TH killsnoop 8 "2015-08-20" "USER COMMANDS"
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.SH NAME
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killsnoop \- Trace signals issued by the kill() syscall. Uses Linux eBPF/bcc.
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.SH SYNOPSIS
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.B killsnoop [\-h] [\-x] [-p PID]
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.SH DESCRIPTION
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killsnoop traces the kill() syscall, to show signals sent via this method. This
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may be useful to troubleshoot failing applications, where an unknown mechanism
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is sending signals.
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This works by tracing the kernel sys_kill() function using dynamic tracing, and
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will need updating to match any changes to this function.
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This makes use of a Linux 4.5 feature (bpf_perf_event_output());
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for kernels older than 4.5, see the version under tools/old,
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which uses an older mechanism.
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Since this uses BPF, only the root user can use this tool.
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.SH REQUIREMENTS
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CONFIG_BPF and bcc.
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.SH OPTIONS
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.TP
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\-h
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Print usage message.
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.TP
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\-x
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Only print failed kill() syscalls.
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.TP
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\-p PID
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Trace this process ID only (filtered in-kernel).
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.SH EXAMPLES
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.TP
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Trace all kill() syscalls:
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#
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.B killsnoop
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.TP
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Trace only kill() syscalls that failed:
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#
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.B killsnoop \-x
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.TP
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Trace PID 181 only:
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#
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.B killsnoop \-p 181
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.SH FIELDS
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.TP
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TIME
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Time of the kill call.
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.TP
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PID
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Source process ID
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.TP
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COMM
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Source process name
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.TP
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SIG
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Signal number. See signal(7).
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.TP
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TPID
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Target process ID
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.TP
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RES
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Result. 0 == success, a negative value (of the error code) for failure.
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.SH OVERHEAD
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This traces the kernel kill function and prints output for each event. As the
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rate of this is generally expected to be low (< 100/s), the overhead is also
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expected to be negligible. If you have an application that is calling a very
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high rate of kill()s for some reason, then test and understand overhead before
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use.
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.SH SOURCE
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This is from bcc.
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.IP
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https://github.com/iovisor/bcc
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.PP
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Also look in the bcc distribution for a companion _examples.txt file containing
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example usage, output, and commentary for this tool.
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.SH OS
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Linux
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.SH STABILITY
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Unstable - in development.
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.SH AUTHOR
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Brendan Gregg
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.SH SEE ALSO
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opensnoop(8), funccount(8)
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