kgdb: Always process the whole breakpoint list on activate or deactivate

This patch fixes 2 edge cases in using kgdb in conjunction with gdb.

1) kgdb_deactivate_sw_breakpoints() should process the entire array of
   breakpoints.  The failure to do so results in breakpoints that you
   cannot remove, because a break point can only be removed if its
   state flag is set to BP_SET.

   The easy way to duplicate this problem is to plant a break point in
   a kernel module and then unload the kernel module.

2) kgdb_activate_sw_breakpoints() should process the entire array of
   breakpoints.  The failure to do so results in missed breakpoints
   when a breakpoint cannot be activated.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

1 files changed, 15 insertions, 8 deletions

diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index 8584eac55e30..2eb517e23514 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -625,7 +625,8 @@ static void kgdb_flush_swbreak_addr(unsigned long addr)
 static int kgdb_activate_sw_breakpoints(void)
 {
         unsigned long addr;
-        int error = 0;
+        int error;
+        int ret = 0;
         int i;
 
         for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
@@ -635,13 +636,16 @@ static int kgdb_activate_sw_breakpoints(void)
                 addr = kgdb_break[i].bpt_addr;
                 error = kgdb_arch_set_breakpoint(addr,
                                 kgdb_break[i].saved_instr);
-                if (error)
-                        return error;
+                if (error) {
+                        ret = error;
+                        printk(KERN_INFO "KGDB: BP install failed: %lx", addr);
+                        continue;
+                }
 
                 kgdb_flush_swbreak_addr(addr);
                 kgdb_break[i].state = BP_ACTIVE;
         }
-        return 0;
+        return ret;
 }
 
 static int kgdb_set_sw_break(unsigned long addr)
@@ -688,7 +692,8 @@ static int kgdb_set_sw_break(unsigned long addr)
 static int kgdb_deactivate_sw_breakpoints(void)
 {
         unsigned long addr;
-        int error = 0;
+        int error;
+        int ret = 0;
         int i;
 
         for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
@@ -697,13 +702,15 @@ static int kgdb_deactivate_sw_breakpoints(void)
                 addr = kgdb_break[i].bpt_addr;
                 error = kgdb_arch_remove_breakpoint(addr,
                                         kgdb_break[i].saved_instr);
-                if (error)
-                        return error;
+                if (error) {
+                        printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr);
+                        ret = error;
+                }
 
                 kgdb_flush_swbreak_addr(addr);
                 kgdb_break[i].state = BP_SET;
         }
-        return 0;
+        return ret;
 }
 
 static int kgdb_remove_sw_break(unsigned long addr)