Ping? :) (2013/09/30 18:21), Masami Hiramatsu wrote: > Fix to find the correct (as much as possible) line information > for listing probes. Without this fix, perf probe --list action > will show incorrect line information as below; > > # perf probe getname_flags > # perf probe -l > probe:getname_flags (on getname_flags@ksrc/linux-3/fs/namei.c) > probe:getname_flags_1 (on getname:-89@x86/include/asm/current.h) > probe:getname_flags_2 (on > user_path_at_empty:-2054@x86/include/asm/current.h) > > The minus line number is obviously wrong, and current.h is not > related to the probe point. Deeper investigation discovered > that there were 2 issues related to this bug, and minor typos too. > > 1st issue is the rack of considering about nested inlined > functions, which causes the wrong (relative) line number. > 2nd issue is that the dwarf line info is not correct at > those points. It points 14th line of current.h. > > Since it seems that the line info includes somewhat unreliable > information, this fixes perf to try to find correct line information > from both of debuginfo and line info as below. > > 1) Probe address is the entry of a function instance > In this case, the line is set as the function declared line. > > 2) Probe address is the entry of an expanded inline function block > In this case, the line is set as the function call-site line. > This means that the line number is relative from the entry line > of caller function (which can be an inlined function if nested) > > 3) Probe address is inside a function instance or an expanded > inline function block > In this case, perf probe queries the line number from lineinfo > and verify the function declared file is same as the file name > queried from lineinfo. > If the file name is different, it is a failure case. The probe > address is shown as symbol+offset. > > 4) Probe address is not in the any function instance > This is a failure case, the probe address is shown as > symbol+offset. > > With this fix, perf probe -l shows correct probe lines as below; > > # perf probe -l > probe:getname_flags (on getname_flags@ksrc/linux-3/fs/namei.c) > probe:getname_flags_1 (on getname:2@ksrc/linux-3/fs/namei.c) > probe:getname_flags_2 (on user_path_at_empty:4@ksrc/linux-3/fs/namei.c) > > Changes at v2: > - Fix typos in the function comments. (Thanks to Namhyung Kim) > - Use die_find_top_inlinefunc instead of die_find_inlinefunc_next. > > Signed-off-by: Masami Hiramatsu <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Paul Mackerras <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Arnaldo Carvalho de Melo <[email protected]> > Cc: Namhyung Kim <[email protected]> > --- > tools/perf/util/dwarf-aux.c | 25 +++++++++++++++++--- > tools/perf/util/dwarf-aux.h | 6 ++++- > tools/perf/util/probe-finder.c | 49 > +++++++++++++++++++++++++++------------- > 3 files changed, 59 insertions(+), 21 deletions(-) > > diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c > index e23bde1..7defd77 100644 > --- a/tools/perf/util/dwarf-aux.c > +++ b/tools/perf/util/dwarf-aux.c > @@ -426,7 +426,7 @@ static int __die_search_func_cb(Dwarf_Die *fn_die, void > *data) > * @die_mem: a buffer for result DIE > * > * Search a non-inlined function DIE which includes @addr. Stores the > - * DIE to @die_mem and returns it if found. Returns NULl if failed. > + * DIE to @die_mem and returns it if found. Returns NULL if failed. > */ > Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr, > Dwarf_Die *die_mem) > @@ -454,15 +454,32 @@ static int __die_find_inline_cb(Dwarf_Die *die_mem, > void *data) > } > > /** > + * die_find_top_inlinefunc - Search the top inlined function at given address > + * @sp_die: a subprogram DIE which including @addr > + * @addr: target address > + * @die_mem: a buffer for result DIE > + * > + * Search an inlined function DIE which includes @addr. Stores the > + * DIE to @die_mem and returns it if found. Returns NULL if failed. > + * Even if several inlined functions are expanded recursively, this > + * doesn't trace it down, and returns the topmost one. > + */ > +Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, > + Dwarf_Die *die_mem) > +{ > + return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem); > +} > + > +/** > * die_find_inlinefunc - Search an inlined function at given address > - * @cu_die: a CU DIE which including @addr > + * @sp_die: a subprogram DIE which including @addr > * @addr: target address > * @die_mem: a buffer for result DIE > * > * Search an inlined function DIE which includes @addr. Stores the > - * DIE to @die_mem and returns it if found. Returns NULl if failed. > + * DIE to @die_mem and returns it if found. Returns NULL if failed. > * If several inlined functions are expanded recursively, this trace > - * it and returns deepest one. > + * it down and returns deepest one. > */ > Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, > Dwarf_Die *die_mem) > diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h > index 8658d41..b4fe90c 100644 > --- a/tools/perf/util/dwarf-aux.h > +++ b/tools/perf/util/dwarf-aux.h > @@ -79,7 +79,11 @@ extern Dwarf_Die *die_find_child(Dwarf_Die *rt_die, > extern Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr, > Dwarf_Die *die_mem); > > -/* Search an inlined function including given address */ > +/* Search the top inlined function including given address */ > +extern Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, > + Dwarf_Die *die_mem); > + > +/* Search the deepest inlined function including given address */ > extern Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, > Dwarf_Die *die_mem); > > diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c > index 371476c..c09e0a9 100644 > --- a/tools/perf/util/probe-finder.c > +++ b/tools/perf/util/probe-finder.c > @@ -1327,8 +1327,8 @@ int debuginfo__find_probe_point(struct debuginfo *self, > unsigned long addr, > struct perf_probe_point *ppt) > { > Dwarf_Die cudie, spdie, indie; > - Dwarf_Addr _addr, baseaddr; > - const char *fname = NULL, *func = NULL, *tmp; > + Dwarf_Addr _addr = 0, baseaddr = 0; > + const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp; > int baseline = 0, lineno = 0, ret = 0; > > /* Adjust address with bias */ > @@ -1349,27 +1349,36 @@ int debuginfo__find_probe_point(struct debuginfo > *self, unsigned long addr, > /* Find a corresponding function (name, baseline and baseaddr) */ > if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) { > /* Get function entry information */ > - tmp = dwarf_diename(&spdie); > - if (!tmp || > + func = basefunc = dwarf_diename(&spdie); > + if (!func || > dwarf_entrypc(&spdie, &baseaddr) != 0 || > - dwarf_decl_line(&spdie, &baseline) != 0) > + dwarf_decl_line(&spdie, &baseline) != 0) { > + lineno = 0; > goto post; > - func = tmp; > + } > > - if (addr == (unsigned long)baseaddr) > + if (addr == (unsigned long)baseaddr) { > /* Function entry - Relative line number is 0 */ > lineno = baseline; > - else if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr, > - &indie)) { > + fname = dwarf_decl_file(&spdie); > + goto post; > + } > + > + /* Track down the inline functions step by step */ > + while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr, > + &indie)) { > + /* There is an inline function */ > if (dwarf_entrypc(&indie, &_addr) == 0 && > - _addr == addr) > + _addr == addr) { > /* > * addr is at an inline function entry. > * In this case, lineno should be the call-site > - * line number. > + * line number. (overwrite lineinfo) > */ > lineno = die_get_call_lineno(&indie); > - else { > + fname = die_get_call_file(&indie); > + break; > + } else { > /* > * addr is in an inline function body. > * Since lineno points one of the lines > @@ -1377,19 +1386,27 @@ int debuginfo__find_probe_point(struct debuginfo > *self, unsigned long addr, > * be the entry line of the inline function. > */ > tmp = dwarf_diename(&indie); > - if (tmp && > - dwarf_decl_line(&spdie, &baseline) == 0) > - func = tmp; > + if (!tmp || > + dwarf_decl_line(&indie, &baseline) != 0) > + break; > + func = tmp; > + spdie = indie; > } > } > + /* Verify the lineno and baseline are in a same file */ > + tmp = dwarf_decl_file(&spdie); > + if (!tmp || strcmp(tmp, fname) != 0) > + lineno = 0; > } > > post: > /* Make a relative line number or an offset */ > if (lineno) > ppt->line = lineno - baseline; > - else if (func) > + else if (basefunc) { > ppt->offset = addr - (unsigned long)baseaddr; > + func = basefunc; > + } > > /* Duplicate strings */ > if (func) { > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
-- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
