From 34698bcbdf7b0629d6c873b5da7c63073fb45361 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 23 Oct 2008 09:32:58 -0400 Subject: [PATCH] ftrace: dynamic ftrace process only text section The text section stays in memory without ever leaving. With the exception of modules, but modules know how to handle that case. With the dynamic ftrace tracer, we need to make sure that it does not try to modify code that no longer exists. The only safe section is .text. This patch changes the recordmcount script to only record the mcount calls in the .text sections. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- scripts/recordmcount.pl | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl index c1c618cd96f6..6b9fe3eb8360 100755 --- a/scripts/recordmcount.pl +++ b/scripts/recordmcount.pl @@ -109,6 +109,11 @@ if ($#ARGV < 6) { my ($arch, $bits, $objdump, $objcopy, $cc, $ld, $nm, $rm, $mv, $inputfile) = @ARGV; +# Acceptable sections to record. +my %text_sections = ( + ".text" => 1, +); + $objdump = "objdump" if ((length $objdump) == 0); $objcopy = "objcopy" if ((length $objcopy) == 0); $cc = "gcc" if ((length $cc) == 0); @@ -139,7 +144,7 @@ if ($arch eq "x86") { } if ($arch eq "x86_64") { - $section_regex = "Disassembly of section"; + $section_regex = "Disassembly of section\\s+(\\S+):"; $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:"; $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount([+-]0x[0-9a-zA-Z]+)?\$"; $type = ".quad"; @@ -151,7 +156,7 @@ if ($arch eq "x86_64") { $cc .= " -m64"; } elsif ($arch eq "i386") { - $section_regex = "Disassembly of section"; + $section_regex = "Disassembly of section\\s+(\\S+):"; $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:"; $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount\$"; $type = ".long"; @@ -298,7 +303,13 @@ my $text; while () { # is it a section? if (/$section_regex/) { - $read_function = 1; + + # Only record text sections that we know are safe + if (defined($text_sections{$1})) { + $read_function = 1; + } else { + $read_function = 0; + } # print out any recorded offsets update_funcs() if ($text_found); -- 2.30.2