diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index 55cb28860b3..cb6cf9729a0 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,11 @@
+2009-11-10  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR ada/20548
+	* system-linux-alpha.ads (Stack_Check_Probes): Set to true.
+	* system-linux-hppa.ads (Stack_Check_Probes): Likewise.
+	* system-linux-sparc.ads (Stack_Check_Probes): Likewise.
+	* system-linux-sparcv9.ads (Stack_Check_Probes): Likewise.
+
 2009-11-10  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* system-linux-alpha.ads (AAMP, Compiler_System_Version, OpenVMS,
diff --git a/gcc/ada/system-linux-alpha.ads b/gcc/ada/system-linux-alpha.ads
index c4f4c902029..721247553ce 100644
--- a/gcc/ada/system-linux-alpha.ads
+++ b/gcc/ada/system-linux-alpha.ads
@@ -127,7 +127,7 @@ private
    Preallocated_Stacks       : constant Boolean := False;
    Signed_Zeros              : constant Boolean := True;
    Stack_Check_Default       : constant Boolean := False;
-   Stack_Check_Probes        : constant Boolean := False;
+   Stack_Check_Probes        : constant Boolean := True;
    Stack_Check_Limits        : constant Boolean := False;
    Support_64_Bit_Divides    : constant Boolean := True;
    Support_Aggregates        : constant Boolean := True;
diff --git a/gcc/ada/system-linux-hppa.ads b/gcc/ada/system-linux-hppa.ads
index a23ebde1c9c..97900432a67 100644
--- a/gcc/ada/system-linux-hppa.ads
+++ b/gcc/ada/system-linux-hppa.ads
@@ -129,7 +129,7 @@ private
    Preallocated_Stacks       : constant Boolean := False;
    Signed_Zeros              : constant Boolean := True;
    Stack_Check_Default       : constant Boolean := False;
-   Stack_Check_Probes        : constant Boolean := False;
+   Stack_Check_Probes        : constant Boolean := True;
    Stack_Check_Limits        : constant Boolean := False;
    Support_64_Bit_Divides    : constant Boolean := True;
    Support_Aggregates        : constant Boolean := True;
diff --git a/gcc/ada/system-linux-sparc.ads b/gcc/ada/system-linux-sparc.ads
index 5dd136849d3..69ac9f25b10 100644
--- a/gcc/ada/system-linux-sparc.ads
+++ b/gcc/ada/system-linux-sparc.ads
@@ -127,7 +127,7 @@ private
    Preallocated_Stacks       : constant Boolean := False;
    Signed_Zeros              : constant Boolean := True;
    Stack_Check_Default       : constant Boolean := False;
-   Stack_Check_Probes        : constant Boolean := False;
+   Stack_Check_Probes        : constant Boolean := True;
    Stack_Check_Limits        : constant Boolean := False;
    Support_64_Bit_Divides    : constant Boolean := True;
    Support_Aggregates        : constant Boolean := True;
diff --git a/gcc/ada/system-linux-sparcv9.ads b/gcc/ada/system-linux-sparcv9.ads
index 27cf01ee52d..9a42b3d4ae8 100644
--- a/gcc/ada/system-linux-sparcv9.ads
+++ b/gcc/ada/system-linux-sparcv9.ads
@@ -127,7 +127,7 @@ private
    Preallocated_Stacks       : constant Boolean := False;
    Signed_Zeros              : constant Boolean := True;
    Stack_Check_Default       : constant Boolean := False;
-   Stack_Check_Probes        : constant Boolean := False;
+   Stack_Check_Probes        : constant Boolean := True;
    Stack_Check_Limits        : constant Boolean := False;
    Support_64_Bit_Divides    : constant Boolean := True;
    Support_Aggregates        : constant Boolean := True;