This is a note to let you know that I've just added the patch titled perf probe: Fix to show function entry line as probe-able to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: perf-probe-fix-to-show-function-entry-line-as-probe-able.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 91e2f539eeda26ab00bd03fae8dc434c128c85ed Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Date: Thu, 24 Oct 2019 18:12:54 +0900 Subject: perf probe: Fix to show function entry line as probe-able From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> commit 91e2f539eeda26ab00bd03fae8dc434c128c85ed upstream. Fix die_walk_lines() to list the function entry line correctly. Since the dwarf_entrypc() does not return the entry pc if the DIE has only range attribute, __die_walk_funclines() fails to list the declaration line (entry line) in that case. To solve this issue, this introduces die_entrypc() which correctly returns the entry PC (the first address range) even if the DIE has only range attribute. With this fix die_walk_lines() shows the function entry line is able to probe correctly. Fixes: 4cc9cec636e7 ("perf probe: Introduce lines walker interface") Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Namhyung Kim <namhyung@xxxxxxxxxx> Link: http://lore.kernel.org/lkml/157190837419.1859.4619125803596816752.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Cc: Thomas Backlund <tmb@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/perf/util/dwarf-aux.c | 24 +++++++++++++++++++++++- tools/perf/util/dwarf-aux.h | 3 +++ 2 files changed, 26 insertions(+), 1 deletion(-) --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -308,6 +308,28 @@ bool die_is_func_def(Dwarf_Die *dw_die) } /** + * die_entrypc - Returns entry PC (the lowest address) of a DIE + * @dw_die: a DIE + * @addr: where to store entry PC + * + * Since dwarf_entrypc() does not return entry PC if the DIE has only address + * range, we have to use this to retrieve the lowest address from the address + * range attribute. + */ +int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr) +{ + Dwarf_Addr base, end; + + if (!addr) + return -EINVAL; + + if (dwarf_entrypc(dw_die, addr) == 0) + return 0; + + return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0; +} + +/** * die_is_func_instance - Ensure that this DIE is an instance of a subprogram * @dw_die: a DIE * @@ -720,7 +742,7 @@ static int __die_walk_funclines(Dwarf_Di /* Handle function declaration line */ fname = dwarf_decl_file(sp_die); if (fname && dwarf_decl_line(sp_die, &lineno) == 0 && - dwarf_entrypc(sp_die, &addr) == 0) { + die_entrypc(sp_die, &addr) == 0) { lw.retval = callback(fname, lineno, addr, data); if (lw.retval != 0) goto done; --- a/tools/perf/util/dwarf-aux.h +++ b/tools/perf/util/dwarf-aux.h @@ -29,6 +29,9 @@ int cu_walk_functions_at(Dwarf_Die *cu_d /* Get DW_AT_linkage_name (should be NULL for C binary) */ const char *die_get_linkage_name(Dwarf_Die *dw_die); +/* Get the lowest PC in DIE (including range list) */ +int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr); + /* Ensure that this DIE is a subprogram and definition (not declaration) */ bool die_is_func_def(Dwarf_Die *dw_die); Patches currently in stable-queue which might be from mhiramat@xxxxxxxxxx are queue-5.4/perf-probe-fix-to-probe-a-function-which-has-no-entr.patch queue-5.4/x86-insn-add-some-intel-instructions-to-the-opcode-m.patch queue-5.4/perf-probe-fix-to-show-function-entry-line-as-probe-able.patch queue-5.4/perf-probe-fix-to-show-ranges-of-variables-in-functi.patch queue-5.4/tracing-kprobe-check-whether-the-non-suffixed-symbol.patch queue-5.4/perf-probe-fix-to-find-range-only-function-instance.patch queue-5.4/perf-probe-walk-function-lines-in-lexical-blocks.patch queue-5.4/perf-probe-fix-to-list-probe-event-with-correct-line.patch queue-5.4/perf-probe-skip-end-of-sequence-and-non-statement-li.patch queue-5.4/perf-probe-return-a-better-scope-die-if-there-is-no-.patch queue-5.4/perf-probe-fix-to-show-inlined-function-callsite-wit.patch queue-5.4/perf-probe-fix-to-show-calling-lines-of-inlined-func.patch queue-5.4/selftests-net-fix-printf-format-warnings-on-arm.patch queue-5.4/selftests-proc-make-va_max-1mb.patch queue-5.4/perf-probe-fix-to-probe-an-inline-function-which-has.patch queue-5.4/perf-probe-skip-overlapped-location-on-searching-var.patch queue-5.4/perf-probe-filter-out-instances-except-for-inlined-s.patch