Re: Systemtap probe for Signals

[Li Guanglei <guanglei at cn dot ibm dot com>]

Hi,

 Beside the probe points in your tapset, I'd like to probe the 
following signal related kernel functions:

 1. do_sigpending
    It is used to suspend signals. Called by sys_rt_sigpending and 
sys_sigpending

 2. handle_signal
    It is called when the kernel want to invoke the signal handlers. 
Called by do_signal.

 3. do_sigaction
    It is called by sys_sigaction, compat_sys_rt_sigaction, 
compat_sys_rt_sigaction, sys_rt_sigaction, sys_signal. It is 
corresponding to the signal() and sigaction() calles from use app.

 4. sigprocmask
    It is called by sys_sigprocmask, sys_rt_sigprocmask.

  And I found you put a point on sig_ignored. But I don't think 
sig_ignored is used to ignore a signal. It is only used to check 
whether or not a signal has been ignored.

  And another comment is about signal.sendsig and 
signal.send_sig_queue. The difference between send_signal and 
send*sigqueue is that send_signal will alloc a sigqueue before adding 
a signal into that queue. But their intention are almost the same: 
sending a signal to a process. I am not sure whether we could combine 
them into one probe or leave it unchanged.

- Guanglei