[Bug lket/3536] New: lket does not trace the right pid and appname

[Bug lket/3536] New: lket does not trace the right pid and appname

[eteo at redhat dot com]

If you perform the following two one-liner scripts, it will not give similar
trace results:

(1) stap -p2 -bM -e 'probe addevent.iosyscall.open {}' 
(2) stap -ve 'probe syscall.open { printf("%s(%d): %s\n", execname(), pid(),
argstr)} '

outputs:
(1) 9.302127 CPU:0 PID:2399 APPNAME:(null) EVT_NAME:iosyscall.open.entry
filename:/dev/bus/usb/002/001,flags:2,mode:1,
9.302163 CPU:0 PID:2399 APPNAME:(null) EVT_NAME:iosyscall.open.entry
filename:/dev/bus/usb/002/003,flags:2,mode:1,
(2) pcscd(2395): "/dev/bus/usb/002/001", O_RDWR
pcscd(2395): "/dev/bus/usb/002/003", O_RDWR

Looks like the pid from the lket trace refers to tid(). APPNAME is pcscd but
it's displayed as (null).

-- 
           Summary: lket does not trace the right pid and appname
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: critical
          Priority: P2
         Component: lket
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: eteo at redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=3536

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[Bug lket/3536] lket does not trace the right pid and appname

[guanglei at cn dot ibm dot com]

------- Additional Comments From guanglei at cn dot ibm dot com  2006-11-17 14:06 -------
LKET will log only the tid for smaller trace data size and faster speed. But
LKET will trace the fork event by default, so the relation between tid,pid,ppid
could be figured out by looking at fork events.

The problem is that, when lket-b2a record the relation of pid/appname, it does
record pid and appname, but when at a later stage lket-b2a retrieve the appname
for a process, it use tid instead of pid to search, and then it will return NULL.

I will fix this in lket-b2a.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|systemtap at sources dot    |guanglei at cn dot ibm dot
                   |redhat dot com              |com
             Status|NEW                         |ASSIGNED


http://sourceware.org/bugzilla/show_bug.cgi?id=3536

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