[Bug runtime/6417] New: Wildcard probe hangs system

[Bug runtime/6417] New: Wildcard probe hangs system

[ananth at in dot ibm dot com]

stap on a simple script:

probe module("ext3").function("*')
{
   printf("%s\n", probefunc());
}

causes the system to hang. Different cpus on the system experience softlockup
leading sometimes to a system hang/crash. Problem more easily recreatable on
POWERPC.

-- 
           Summary: Wildcard probe hangs system
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: critical
          Priority: P1
         Component: runtime
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: ananth at in dot ibm dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=6417

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[Bug runtime/6417] Wildcard probe hangs system

[ananth at in dot ibm dot com]

------- Additional Comments From ananth at in dot ibm dot com  2008-04-16 09:37 -------
Of course, the probe statement in comment is

probe module("ext3").function("*")

not

probe module("ext3").function("*')

-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=6417

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[Bug runtime/6417] Wildcard probe hangs system

[srinivasa at in dot ibm dot com]

------- Additional Comments From srinivasa at in dot ibm dot com  2008-04-16 09:53 -------
Created an attachment (id=2700)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=2700&action=view)
Patch to blacklist atomic_* functions.

When we use wildcards in scripts, Systemtap probes all functions present in the

file(s). For example, probe module("ext3").function("*") will probe all
functions called in fs/ext3/*.c, which includes atomic_* functions too.
But atomic_* functions are used in systemtap/kprobes and might be in
handlers,so we need to blacklist these functions.

In addition, get_bh() and put_bh() are both inline functions but in turn use
atomic functions. Ideally the atomic_* blacklist needs to take care of this,
but doesn't (probably 'cos of the way inlines are handled currently). So,
blacklist them too.


-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=6417

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[Bug runtime/6417] Wildcard probe hangs system

[srinivasa at in dot ibm dot com]

------- Additional Comments From srinivasa at in dot ibm dot com  2008-04-17 08:13 -------
patch is commited with commit id a11f4bae4d8bf226520308b44342a14cd02cb196.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://sourceware.org/bugzilla/show_bug.cgi?id=6417

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