kgdb: fix kgdb_validate_break_address to perform a mem write

[sfrench/cifs-2.6.git] / kernel / kgdb.c

diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index 3ec23c3ec97fae75910a399b4b7200fb6a9169c6..c0d45b2c4d790f32b66e86bd16f5c7bd9769da38 100644 (file)
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -166,13 +166,6 @@ early_param("nokgdbroundup", opt_nokgdbroundup);
  * Weak aliases for breakpoint management,
  * can be overriden by architectures when needed:
  */
-int __weak kgdb_validate_break_address(unsigned long addr)
-{
-       char tmp_variable[BREAK_INSTR_SIZE];
-
-       return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE);
-}
-
 int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
 {
        int err;
@@ -191,6 +184,25 @@ int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
                                  (char *)bundle, BREAK_INSTR_SIZE);
 }
 
+int __weak kgdb_validate_break_address(unsigned long addr)
+{
+       char tmp_variable[BREAK_INSTR_SIZE];
+       int err;
+       /* Validate setting the breakpoint and then removing it.  In the
+        * remove fails, the kernel needs to emit a bad message because we
+        * are deep trouble not being able to put things back the way we
+        * found them.
+        */
+       err = kgdb_arch_set_breakpoint(addr, tmp_variable);
+       if (err)
+               return err;
+       err = kgdb_arch_remove_breakpoint(addr, tmp_variable);
+       if (err)
+               printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "
+                  "memory destroyed at: %lx", addr);
+       return err;
+}
+
 unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
 {
        return instruction_pointer(regs);