Messages in this thread | | | Subject | Re: [PATCH] perf probe: Fix add event failed when 32-bit perf running in 64-bit kernel | From | Yang Jihong <> | Date | Thu, 15 Jul 2021 09:20:01 +0800 |
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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)
Can I put the following diff together and submit a v2 patch? > > 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; > >
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