Messages in this thread | | | Date | Thu, 15 Jul 2021 13:58:21 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH] perf probe: Fix add event failed when 32-bit perf running in 64-bit kernel |
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On Thu, 15 Jul 2021 09:20:01 +0800 Yang Jihong <yangjihong1@huawei.com> wrote:
> Hello Hiramatsu, > > On 2021/7/14 16:35, Masami Hiramatsu wrote: > > Hi Yang, > > > > On Wed, 14 Jul 2021 14:54:32 +0800 > > Yang Jihong <yangjihong1@huawei.com> wrote: > > > >> The "address" member of "struct probe_trace_point" uses long data type. > >> If kernel is 64-bit and perf program is 32-bit, size of "address" variable is > >> 32 bits. As a result, upper 32 bits of address read from kernel are truncated, > >> An error occurs during address comparison in kprobe_warn_out_range function. > > > > Good catch! > > I didn't imagine that such a use case. But that is important because perf > > probe can be used for cross-arch probe definition too. > > > >> > >> Before: > >> > >> # perf probe -a schedule > >> schedule is out of .text, skip it. > >> Error: Failed to add events. > >> > >> Solution: > >> Change data type of "address" variable to u64 and change corresponding > >> address printing and value assignment. > > > > OK, as far as I can see, the other parts of the perf also uses u64 for > > "address" storing variables. (e.g. symbols, maps etc.) > > > >> > >> After: > >> > >> # perf.new.new probe -a schedule > >> Added new event: > >> probe:schedule (on schedule) > >> > >> You can now use it in all perf tools, such as: > >> > >> perf record -e probe:schedule -aR sleep 1 > >> > >> # perf probe -l > >> probe:schedule (on schedule) > > > > I think you missed one thing here. > > Usually, this shows the filename and line number of schedule(). > Yes, I tried the following diff and now it can show the filename (as is > function entry, relative line number is 0), thank you very much :) > > The test result in my environment is as follows: > > # perf probe -a schedule > Added new event: > probe:schedule (on schedule) > > You can now use it in all perf tools, such as: > > perf record -e probe:schedule -aR sleep 1 > > # perf probe -l schedule -k vmlinux.debug > probe:schedule (on schedule@kernel/sched/core.c) >
OK, good!
> > Can I put the following diff together and submit a v2 patch?
Yes, please include this fix in your patch, because it is what your patch has to do :)
Thank you!
> > > > Could you try below diff? > > > > diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c > > index 7d2ba8419b0c..609ca1671501 100644 > > --- a/tools/perf/util/dwarf-aux.c > > +++ b/tools/perf/util/dwarf-aux.c > > @@ -113,14 +113,14 @@ static Dwarf_Line *cu_getsrc_die(Dwarf_Die *cu_die, Dwarf_Addr addr) > > * > > * Find a line number and file name for @addr in @cu_die. > > */ > > -int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr, > > - const char **fname, int *lineno) > > +int cu_find_lineinfo(Dwarf_Die *cu_die, Dwarf_Addr addr, > > + const char **fname, int *lineno) > > { > > Dwarf_Line *line; > > Dwarf_Die die_mem; > > Dwarf_Addr faddr; > > > > - if (die_find_realfunc(cu_die, (Dwarf_Addr)addr, &die_mem) > > + if (die_find_realfunc(cu_die, addr, &die_mem) > > && die_entrypc(&die_mem, &faddr) == 0 && > > faddr == addr) { > > *fname = dwarf_decl_file(&die_mem); > > @@ -128,7 +128,7 @@ int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr, > > goto out; > > } > > > > - line = cu_getsrc_die(cu_die, (Dwarf_Addr)addr); > > + line = cu_getsrc_die(cu_die, addr); > > if (line && dwarf_lineno(line, lineno) == 0) { > > *fname = dwarf_linesrc(line, NULL, NULL); > > if (!*fname) > > diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h > > index cb99646843a9..7ee0fa19b5c4 100644 > > --- a/tools/perf/util/dwarf-aux.h > > +++ b/tools/perf/util/dwarf-aux.h > > @@ -19,7 +19,7 @@ const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname); > > const char *cu_get_comp_dir(Dwarf_Die *cu_die); > > > > /* Get a line number and file name for given address */ > > -int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr, > > +int cu_find_lineinfo(Dwarf_Die *cudie, Dwarf_Addr addr, > > const char **fname, int *lineno); > > > > /* Walk on functions at given address */ > > diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c > > index 8ba01bbdf05c..50d861a80f57 100644 > > --- a/tools/perf/util/probe-finder.c > > +++ b/tools/perf/util/probe-finder.c > > @@ -1727,7 +1727,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, u64 addr, > > } > > > > /* Find a corresponding line (filename and lineno) */ > > - cu_find_lineinfo(&cudie, addr, &fname, &lineno); > > + cu_find_lineinfo(&cudie, (Dwarf_Addr)addr, &fname, &lineno); > > /* Don't care whether it failed or not */ > > > > /* Find a corresponding function (name, baseline and baseaddr) */ > > @@ -1828,8 +1828,7 @@ static int line_range_add_line(const char *src, unsigned int lineno, > > } > > > > static int line_range_walk_cb(const char *fname, int lineno, > > - Dwarf_Addr addr __maybe_unused, > > - void *data) > > + Dwarf_Addr addr, void *data) > > { > > struct line_finder *lf = data; > > const char *__fname; > > > >
-- Masami Hiramatsu <mhiramat@kernel.org>
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