Re: [PATCH] perf probe: Fix add event failed when 32-bit perf running in 64-bit kernel
From: Yang Jihong <hidden>
Date: 2021-07-15 01:20:23
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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 [off-list ref] wrote:quoted
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.quoted
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.)quoted
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?quoted hunk ↗ jump to hunk
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;