[PATCH 0/3] checkstack: bug fix and minor improvements

[PATCH 0/3] checkstack: bug fix and minor improvements

[Heiko Carstens]

While trying to use the checkstack script to print the stack usage of all
functions, I noticed that this is not possible without changing it. In
addition the current output contains a bug, and the output can be improved.

Therefore fix the bug and improve the script a bit.

Heiko Carstens (3):
  checkstack: fix printed address
  checkstack: sort output by size and function name
  checkstack: allow to pass MINSTACKSIZE parameter

 Makefile              |  6 ++++--
 scripts/checkstack.pl | 27 +++++++++++++++++++--------
 2 files changed, 23 insertions(+), 10 deletions(-)

-- 
2.39.2

[PATCH 1/3] checkstack: fix printed address

[Heiko Carstens]

All addresses printed by checkstack have an extra incorrect 0 appended at
the end.

This was introduced with commit 677f1410e058 ("scripts/checkstack.pl: don't
display $dre as different entity"): since then the address is taken from
the line which contains the function name, instead of the line which
contains stack consumption. E.g. on s390:

0000000000100a30 <do_one_initcall>:
...
  100a44:       e3 f0 ff 70 ff 71       lay     %r15,-144(%r15)

So the used regex which matches spaces and hexadecimal numbers to extract
an address now matches a different substring. Subsequently replacing spaces
with 0 appends a zero at the and, instead of replacing leading spaces.

Fix this by using the proper regex, and simplify the code a bit.

Fixes: 677f1410e058 ("scripts/checkstack.pl: don't display $dre as different entity")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 scripts/checkstack.pl | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/scripts/checkstack.pl b/scripts/checkstack.pl
index d83ba5d8f3f4..f27d552aec43 100755
--- a/scripts/checkstack.pl
+++ b/scripts/checkstack.pl
@@ -138,15 +138,11 @@ $total_size = 0;
 while (my $line = <STDIN>) {
 	if ($line =~ m/$funcre/) {
 		$func = $1;
-		next if $line !~ m/^($xs*)/;
+		next if $line !~ m/^($x*)/;
 		if ($total_size > $min_stack) {
 			push @stack, "$intro$total_size\n";
 		}
-
-		$addr = $1;
-		$addr =~ s/ /0/g;
-		$addr = "0x$addr";
-
+		$addr = "0x$1";
 		$intro = "$addr $func [$file]:";
 		my $padlen = 56 - length($intro);
 		while ($padlen > 0) {
-- 
2.39.2

[PATCH 2/3] checkstack: sort output by size and function name

[Heiko Carstens]

Sort output by size and in addition by function name. This increases
readability for cases where there are many functions with the same stack
usage.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 scripts/checkstack.pl | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/scripts/checkstack.pl b/scripts/checkstack.pl
index f27d552aec43..13408714ba0f 100755
--- a/scripts/checkstack.pl
+++ b/scripts/checkstack.pl
@@ -189,5 +189,20 @@ if ($total_size > $min_stack) {
 	push @stack, "$intro$total_size\n";
 }
 
-# Sort output by size (last field)
-print sort { ($b =~ /:\t*(\d+)$/)[0] <=> ($a =~ /:\t*(\d+)$/)[0] } @stack;
+# Sort output by size (last field) and function name if size is the same
+sub sort_lines {
+	my ($a, $b) = @_;
+
+	my $num_a = $1 if $a =~ /:\t*(\d+)$/;
+	my $num_b = $1 if $b =~ /:\t*(\d+)$/;
+	my $func_a = $1 if $a =~ / (.*):/;
+	my $func_b = $1 if $b =~ / (.*):/;
+
+	if ($num_a != $num_b) {
+		return $num_b <=> $num_a;
+	} else {
+		return $func_a cmp $func_b;
+	}
+}
+
+print sort { sort_lines($a, $b) } @stack;
-- 
2.39.2

[PATCH 3/3] checkstack: allow to pass MINSTACKSIZE parameter

[Heiko Carstens]

The checkstack script omits all functions with a stack usage of less than
100 bytes. However the script already has support for a parameter which
allows to override the default, but it cannot be set with

$ make checkstack

Add a MINSTACKSIZE parameter which allows to change the default. This might
be useful in order to print the stack usage of all functions, or only those
with large stack usage:

$ make checkstack MINSTACKSIZE=0
$ make checkstack MINSTACKSIZE=800

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 Makefile | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 724c79bebe72..b90413e7e590 100644
--- a/Makefile
+++ b/Makefile
@@ -1576,7 +1576,8 @@ help:
 	 echo  '                    (default: $(INSTALL_HDR_PATH))'; \
 	 echo  ''
 	@echo  'Static analysers:'
-	@echo  '  checkstack      - Generate a list of stack hogs'
+	@echo  '  checkstack      - Generate a list of stack hogs and consider all functions'
+	@echo  '                    with a stack size larger than MINSTACKSIZE (default: 100)'
 	@echo  '  versioncheck    - Sanity check on version.h usage'
 	@echo  '  includecheck    - Check for duplicate included header files'
 	@echo  '  export_report   - List the usages of all exported symbols'
@@ -2016,9 +2017,10 @@ CHECKSTACK_ARCH := $(SUBARCH)
 else
 CHECKSTACK_ARCH := $(ARCH)
 endif
+MINSTACKSIZE	?= 100
 checkstack:
 	$(OBJDUMP) -d vmlinux $$(find . -name '*.ko') | \
-	$(PERL) $(srctree)/scripts/checkstack.pl $(CHECKSTACK_ARCH)
+	$(PERL) $(srctree)/scripts/checkstack.pl $(CHECKSTACK_ARCH) $(MINSTACKSIZE)
 
 kernelrelease:
 	@$(filechk_kernel.release)
-- 
2.39.2