Commit 585e93ae authored by Eric Sandeen's avatar Eric Sandeen Committed by Linus Torvalds
Browse files

find dynamic stack allocations in checkstack.pl 



Currently, checkstack.pl only looks for fixed subtractions from the stack
pointer.  However, things like this:

void function(int size)
{
        char stackbuster[size << 2];
...

are certainly worth pointing out, I think.

This could perhaps be done more cleanly, and the following patch only
adds "dynamic" REs for x86 and x86_64, but it works:

0x00b0 crypto_cbc_decrypt_inplace [cbc]:                Dynamic (%rax)
0x00ad crypto_pcbc_decrypt_inplace [pcbc]:              Dynamic (%rax)
0x02f6 crypto_pcbc_encrypt_inplace [pcbc]:              Dynamic (%rax)
0x036c _crypto_xcbc_digest_setkey [xcbc]:               Dynamic (%rax)
...

(Inspired by Keith Owens' old stack-check script)

Signed-off-by: default avatarEric Sandeen <sandeen@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 545e4006

scripts/checkstack.pl

+23 −1
Original line number Diff line number Diff line
@@ -26,8 +26,12 @@ 
# $& (whole re) matches the complete objdump line with the stack growth

# $1 (first bracket) matches the size of the stack growth

#

# $dre is similar, but for dynamic stack redutions:

# $& (whole re) matches the complete objdump line with the stack growth

# $1 (first bracket) matches the dynamic amount of the stack growth

#

# use anything else and feel the pain ;)

my (@stack, $re, $x, $xs);

my (@stack, $re, $dre, $x, $xs);

{

	my $arch = shift;

	if ($arch eq "") {
@@ -46,9 +50,11 @@ my (@stack, $re, $x, $xs); 
	} elsif ($arch =~ /^i[3456]86$/) {

		#c0105234:       81 ec ac 05 00 00       sub    $0x5ac,%esp

		$re = qr/^.*[as][du][db]    \$(0x$x{1,8}),\%esp$/o;

		$dre = qr/^.*[as][du][db]    (%.*),\%esp$/o;

	} elsif ($arch eq 'x86_64') {

		#    2f60:	48 81 ec e8 05 00 00 	sub    $0x5e8,%rsp

		$re = qr/^.*[as][du][db]    \$(0x$x{1,8}),\%rsp$/o;

		$dre = qr/^.*[as][du][db]    (\%.*),\%rsp$/o;

	} elsif ($arch eq 'ia64') {

		#e0000000044011fc:       01 0f fc 8c     adds r12=-384,r12

		$re = qr/.*adds.*r12=-(([0-9]{2}|[3-9])[0-9]{2}),r12/o;
@@ -141,6 +147,22 @@ while (my $line = <STDIN>) { 
		next if ($size < 100);

		push @stack, "$intro$size\n";

	}

	elsif (defined $dre && $line =~ m/$dre/) {

		my $size = "Dynamic ($1)";



		next if $line !~ m/^($xs*)/;

		my $addr = $1;

		$addr =~ s/ /0/g;

		$addr = "0x$addr";



		my $intro = "$addr $func [$file]:";

		my $padlen = 56 - length($intro);

		while ($padlen > 0) {

			$intro .= '	';

			$padlen -= 8;

		}

		push @stack, "$intro$size\n";

	}

}



print sort bysize @stack;

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