Sure, inlined functions are embedded in a caller function, so the
closest function is the correct owner.
However, I meant local-scope functions can have same name if
they are defined in different scope. And even though, both of
them are shown in kallsyms. This mean, you can see the functions
which have real different existence but have same symbol.
Would you mean systemtap should not probe those name-conflicted
functions?
Hmm, here is what I got with your patch;
$ stap --kelf -e 'probe kernel.function("do_open"){}' -p2
# probes
kernel.function("do_open@arch/x86/kernel/apm_32.c:1557") /* pc=<do_open+0x0> */ /* <- kernel.function("do_open") */
kernel.function("do_open@fs/block_dev.c:928") /* pc=<do_open+0x0> */ /* <- kernel.function("do_open") */
kernel.function("do_open@fs/nfsctl.c:24") /* pc=<sys_nfsservctl+0x55> */ /* <- kernel.function("do_open") */
kernel.function("do_open@ipc/mqueue.c:630") /* pc=<do_open+0x0> */ /* <- kernel.function("do_open") */
Without your patch;
$ stap -e 'probe kernel.function("do_open"){}' -p2
# probes
kernel.function("do_open@arch/x86/kernel/apm_32.c:1557") /* pc=0x10382 */ /* <- kernel.function("do_open") */
kernel.function("do_open@fs/block_dev.c:928") /* pc=0xa0750 */ /* <- kernel.function("do_open") */
kernel.function("do_open@fs/nfsctl.c:24") /* pc=0xa6411 */ /* <- kernel.function("do_open") */
kernel.function("do_open@ipc/mqueue.c:630") /* pc=0xc55a6 */ /* <- kernel.function("do_open") */
Obviously, the 3rd "do_open" is fully inlined, so it can be
correctly handled by kprobes, because it has different
symbol(sys_nfsservctl). However, other "do_open" have
same symbol(do_open). these will be put on same
address (at the first symbol on kallsyms list).
So, we need a bridge for the gap of function addresses
between kallsyms and dwarf.
[...]
I agree with you, we need to change both of systemtap and kernel.
Thank you,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
--
