uprobe symbols with @GLIBC...

[Paul Clarke <pc@us.ibm.com>]

Greetings,

(New user for perf probe -x...)

How does one set a dynamic tracepoint for user-mode symbols with "@" 
qualifiers?

# perf probe -F -x /lib/libpthread.so.0 --filter='pthread_create*'
pthread_create@@GLIBC_2.1
pthread_create@GLIBC_2.0

# perf probe -v -x /lib/libpthread.so.0 pthread_create@GLIBC_2.0
probe-definition(0): pthread_create@GLIBC_2.0
symbol:pthread_create file:GLIBC_2.0 line:0 offset:0 return:0 lazy:(null)
0 arguments
Failed to open debuginfo file.
   Error: Failed to add events. (-2)

# perf probe -v -x /lib/libpthread.so.0 pthread_create
probe-definition(0): pthread_create
symbol:pthread_create file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
Could not open debuginfo. Try to use symbols.
no symbols found in /usr/lib/libpthread-2.18.so, maybe install a debug 
package?
Failed to find symbol pthread_create in /usr/lib/libpthread-2.18.so
   Error: Failed to add events. (-2)

Symbols without such qualifiers work fine:

# perf probe -F -x /lib/libpthread.so.0 --filter='pthread_detach*'
pthread_detach

# perf probe -v -x /lib/libpthread.so.0 pthread_detach
probe-definition(0): pthread_detach
symbol:pthread_detach file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
Could not open debuginfo. Try to use symbols.
Opening /sys/kernel/debug/tracing/uprobe_events write=1
Added new event:
Writing event: p:probe_libpthread/pthread_detach 
/usr/lib/libpthread-2.18.so:0x8b30
   probe_libpthread:pthread_detach (on pthread_detach in 
/usr/lib/libpthread-2.18.so)

You can now use it in all perf tools, such as:

         perf record -e probe_libpthread:pthread_detach -aR sleep 1

--
Regards,
Paul Clarke, IBM