[lttng-dev] ERROR: No buffer space available

[Rui Han]

Hi,

I try to modified the lttng2.0 source code for my research. For example, I
try to log the "comm" for the write system call, I add the following filed
in the file x86-64-syscalls-3.0.4_pointers.h located at the path
lttng-modules-2.0.3/instrumentation/syscalls/headers. I modify the
TRACE_EVENTS() macro from the original one:

#ifndef OVERRIDE_64_sys_write
SC_TRACE_EVENT(sys_write,
TP_PROTO(unsigned int fd, const char * buf, size_t count),
TP_ARGS(fd, buf, count),
TP_STRUCT__entry(__field(unsigned int, fd) __field_hex(const char *, buf)
__field(size_t, count)),
TP_fast_assign(tp_assign(fd, fd) tp_assign(buf, buf) tp_assign(count,
count)),
TP_printk()
)
#endif

to the following one:

#ifndef OVERRIDE_64_sys_write
SC_TRACE_EVENT(sys_write,
TP_PROTO(unsigned int fd, const char * buf, size_t count, struct
task_struct *p),
TP_ARGS(fd, buf, count, p),
TP_STRUCT__entry( __field(unsigned int, fd) __field_hex(const char *,
buf) __field(size_t,
count) __array_text(char, comm, TASK_COMM_LEN)),
TP_fast_assign( tp_assign(fd, fd) tp_assign(buf, buf) tp_assign(count,
2064) tp_memcpy(comm,
p->comm, TASK_COMM_LEN)),
TP_printk()
)
#endif

I add one argument *p and one filed "comm"  for the macro. It was able to
be compiled, however, after reload the lttng modules, It will show the
following error messages when I start lttng.

PERROR: ioctl start session: No buffer space available [in
kernel_start_session() at kernel.c:397]
Error: Starting kernel trace failed

It won't work. Please help me out with this. My next step is try to add
extra fields in the sys_connect macros to enable the logging of the
connected IP/port from the socket. Is this method right? what are other
possible solutions in order to logging the details of the socket
information?

Thank you very much.

Regards,
Rui
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lttng.org/pipermail/lttng-dev/attachments/20120805/ae6421e7/attachment.html>