Re: [PATCH 3/3] tracing: Provide trace events interface for uprobes

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

(2012/04/16 18:19), Srikar Dronamraju wrote:
> From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> 
> Implements trace_event support for uprobes. In its current form it can
> be used to put probes at a specified offset in a file and dump the
> required registers when the code flow passes through the probed address.
> 
> The following example shows how to dump the instruction pointer and %ax
> a register at the probed text address.  Here we are trying to probe
> zfree in /bin/zsh
> 
> # cd /sys/kernel/debug/tracing/
> # cat /proc/`pgrep  zsh`/maps | grep /bin/zsh | grep r-xp
> 00400000-0048a000 r-xp 00000000 08:03 130904 /bin/zsh
> # objdump -T /bin/zsh | grep -w zfree
> 0000000000446420 g    DF .text  0000000000000012  Base        zfree
> # echo 'p /bin/zsh:0x46420 %ip %ax' > uprobe_events
> # cat uprobe_events
> p:uprobes/p_zsh_0x46420 /bin/zsh:0x0000000000046420
> # echo 1 > events/uprobes/enable
> # sleep 20
> # echo 0 > events/uprobes/enable
> # cat trace
> # tracer: nop
> #
> #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
> #              | |       |          |         |
>              zsh-24842 [006] 258544.995456: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
>              zsh-24842 [007] 258545.000270: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
>              zsh-24842 [002] 258545.043929: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
>              zsh-24842 [004] 258547.046129: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
> 
> Acked-by: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

Looks good for me :)

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>


Thanks!


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

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