Thanks lejun.
For the following output, the first called function (the last function show
in ustack) is still not from a process (in this case mysqld).
dtrace -n 'syscall::portfs:entry {ustack();}'
11 60041 portfs:entry
libc.so.1`_portfs+0xa
mysqld`_Z25ep_start_waiting_for_dataP12EP_FILE_INFO+0x55
mysqld`ep_thread_proc+0x194 *====> function of
mysqld is in the middle of th ustack*
libc.so.1`_thr_setup+0x5b
libc.so.1`_lwp_start *===> this
library call is the first call, but who called this function, should a call
always started from function main()?*
11 60041 portfs:entry
libc.so.1`_portfs+0xa
mysqld`ep_thread_proc+0x81
libc.so.1`_thr_setup+0x5b
libc.so.1`_lwp_start
11 60041 portfs:entry
libc.so.1`_portfs+0xa
mysqld`_Z25ep_start_waiting_for_dataP12EP_FILE_INFO+0x55
mysqld`ep_thread_proc+0x194
libc.so.1`_thr_setup+0x5b
libc.so.1`_lwp_start
11 60041 portfs:entry
libc.so.1`_portfs+0xa
mysqld`ep_thread_proc+0x81
libc.so.1`_thr_setup+0x5b
libc.so.1`_lwp_start
11 60041 portfs:entry
libc.so.1`_portfs+0xa
mysqld`_Z25ep_start_waiting_for_dataP12EP_FILE_INFO+0x55
mysqld`ep_thread_proc+0x194
libc.so.1`_thr_setup+0x5b
libc.so.1`_lwp_start
2009/5/4 Zhu, Lejun <[email protected]>
> Try increase "ustackframes", I think the default is 20 and you won't see
> the real entry point when ustack is too deep.
>
> ------------------------------
> *From:* [email protected] [mailto:
> [email protected]] *On Behalf Of *Qihua Wu
> *Sent:* 2009年5月4日 9:59
> *To:* [email protected]
> *Subject:* [dtrace-discuss] output of ustack only shows the library call
> but no program call which called the library
>
> After I run dtrace -n 'syscall::brk:entry {ustack()}', I found some output
> show the function from ONLY library. But libaray is not runnable by itself.
>
>
> 0 59753 brk:entry
> libc.so.1`_brk_unlocked+0xa
> libc.so.1`sbrk+0x20
> libc.so.1`_morecore+0x12b
> libc.so.1`_malloc_unlocked+0x10d
> libc.so.1`malloc+0x2d
> libproc.so.1`optimize_symtab+0x6c
> libproc.so.1`Pbuild_file_symtab+0x787
> libproc.so.1`build_map_symtab+0x36
> libproc.so.1`Pxlookup_by_name+0x6d
> libproc.so.1`Plookup_by_name+0x1c
> libproc.so.1`ps_pglobal_lookup+0x1a
> librtld_db.so.1`_rd_reset64+0x10f
> librtld_db.so.1`rd_reset+0x58
> librtld_db.so.1`rd_new+0x6d
> libproc.so.1`Prd_agent+0x4f
> libproc.so.1`Pxlookup_by_addr+0x55
> libproc.so.1`Plookup_by_addr+0xc
> libdtrace.so.1`dt_print_ustack+0x16b
> libdtrace.so.1`dt_consume_cpu+0x3ae
> libdtrace.so.1`dt_consume_begin+0x92
> ===> The library is not runnable by itself, why the function comes from
> library?
>
> 0 59753 brk:entry
> libc.so.1`_brk_unlocked+0xa
> libc.so.1`sbrk+0x20
> libc.so.1`_morecore+0x27
> libc.so.1`_malloc_unlocked+0x10d
> libc.so.1`malloc+0x2d
> libproc.so.1`optimize_symtab+0x6c
> libproc.so.1`Pbuild_file_symtab+0x787
> libproc.so.1`build_map_symtab+0x36
> libproc.so.1`Pxlookup_by_addr+0x70
> libproc.so.1`Plookup_by_addr+0xc
> libdtrace.so.1`dt_print_ustack+0x16b
> libdtrace.so.1`dt_consume_cpu+0x3ae
> libdtrace.so.1`dt_consume_begin+0x92
> libdtrace.so.1`dtrace_consume+0x114
> libdtrace.so.1`dtrace_work+0xaa
> dtrace`main+0x902
>
> dtrace`_start+0x6c ==> This
> one is better to understand: dtrace is a process calling some library, so
> it makes sense to have the "dtrace`_start+0x6c" as the outer most function.
>
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