> From: Arnaldo Carvalho de Melo [mailto:a...@kernel.org]
>
> Hi Masami,
>
> Have you noticed that sys_select or sys_poll stops after the
> first few lines? Please let me know if you need more info than is below.
>
> [root@zoo ~]# perf probe -L sys_select
> <SyS_select@/home/git/linux/fs/select.c:0>
> 0 SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user
> *, outp,
> fd_set __user *, exp, struct timeval __user *, tvp)
> {
> struct timespec end_time, *to = NULL;
>
> [root@zoo ~]# perf probe -L sys_poll
> <SyS_poll@/home/git/linux/fs/select.c:0>
> 0 SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int,
> nfds,
> int, timeout_msecs)
> {
> struct timespec end_time, *to = NULL;
>
> [root@zoo ~]#
>
> I haven't investigated it too much, if there is some trouble that makes
> 'perf probe -L' to stop like that maybe we should warn the user somehow?
>
> Using -v didn't helped that much:
>
> [root@zoo ~]# perf probe -v -L sys_poll
> Using /root/.debug/.build-id/a8/26726b5ddacfab1f0bade868f1a7924f6b20c4 for
> symbols
> Open Debuginfo file:
> /root/.debug/.build-id/a8/26726b5ddacfab1f0bade868f1a7924f6b20c4
> path: (null)
> Symbol sys_poll address found : ffffffff812297e0
> fname: /home/git/linux/fs/select.c, lineno:957
> New line range: 957 to 2147483647
> path: /home/git/linux/fs/select.c
> <SyS_poll@/home/git/linux/fs/select.c:0>
> 0 SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int,
> nfds,
> int, timeout_msecs)
> {
> struct timespec end_time, *to = NULL;
>
> [root@zoo ~]#
OK, I got what was wrong.
I've ingestigated and found that SYSCALL_DEFINE macro is doing
SYSCALL_DEFINE*(foo,...)
{
body;
}
is expanded as below (on debuginfo)
static inline int SYSC_foo(...)
{
body;
}
int SyS_foo(...) <- is an alias of sys_foo.
{
return SYSC_foo(...);
}
"perf probe -L sys_foo" decodes SyS_foo function and it also
skips inlined functions inside the target function because
those functions are usually defined somewhere else.
Thus, it shows only the first line of sys_foo.
BTW, since SYSC_foo doesn't have no instance, "perf probe -L SYSC_foo"
doesn't show anything.
I think we can avoid this problem by checking whether the inlined function
is defined at the same point of the target function definition.
Thank you,
--
Masami HIRAMATSU
Linux Technology Research Center, System Productivity Research Dept.
Center for Technology Innovation - Systems Engineering
Hitachi, Ltd., Research & Development Group
E-mail: masami.hiramatsu...@hitachi.com
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