Merge tag 'for_linus-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

Pull KGDB/KDB fixes and cleanups from Jason Wessel:
 "Cleanups
   - Clean up compile warnings in kgdboc.c and x86/kernel/kgdb.c
   - Add module event hooks for simplified debugging with gdb
 Fixes
   - Fix kdb to stop paging with 'q' on bta and dmesg
   - Fix for data that scrolls off the vga console due to line wrapping
     when using the kdb pager
 New
   - The debug core registers for kernel module events which allows a
     kernel aware gdb to automatically load symbols and break on entry
     to a kernel module
   - Allow kgdboc=kdb to setup kdb on the vga console"

* tag 'for_linus-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  tty/console: fix warnings in drivers/tty/serial/kgdboc.c
  kdb,vt_console: Fix missed data due to pager overruns
  kdb: Fix dmesg/bta scroll to quit with 'q'
  kgdboc: Accept either kbd or kdb to activate the vga + keyboard kdb shell
  kgdb,x86: fix warning about unused variable
  mips,kgdb: fix recursive page fault with CONFIG_KPROBES
  kgdb: Add module event hooks

4 files changed, 50 insertions, 5 deletions

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 17e073c309e6..9a61738cefc8 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -696,6 +696,22 @@ out:
         return ret;
 }
 
+/*
+ * GDB places a breakpoint at this function to know dynamically
+ * loaded objects. It's not defined static so that only one instance with this
+ * name exists in the kernel.
+ */
+
+static int module_event(struct notifier_block *self, unsigned long val,
+        void *data)
+{
+        return 0;
+}
+
+static struct notifier_block dbg_module_load_nb = {
+        .notifier_call  = module_event,
+};
+
 int kgdb_nmicallback(int cpu, void *regs)
 {
 #ifdef CONFIG_SMP
@@ -824,6 +840,7 @@ static void kgdb_register_callbacks(void)
                 kgdb_arch_init();
                 if (!dbg_is_early)
                         kgdb_arch_late();
+                register_module_notifier(&dbg_module_load_nb);
                 register_reboot_notifier(&dbg_reboot_notifier);
                 atomic_notifier_chain_register(&panic_notifier_list,
                                                &kgdb_panic_event_nb);
@@ -847,6 +864,7 @@ static void kgdb_unregister_callbacks(void)
         if (kgdb_io_module_registered) {
                 kgdb_io_module_registered = 0;
                 unregister_reboot_notifier(&dbg_reboot_notifier);
+                unregister_module_notifier(&dbg_module_load_nb);
                 atomic_notifier_chain_unregister(&panic_notifier_list,
                                                &kgdb_panic_event_nb);
                 kgdb_arch_exit();
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 07c9bbb94a0b..b03e0e814e43 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -129,6 +129,8 @@ kdb_bt(int argc, const char **argv)
                 }
                 /* Now the inactive tasks */
                 kdb_do_each_thread(g, p) {
+                        if (KDB_FLAG(CMD_INTERRUPT))
+                                return 0;
                         if (task_curr(p))
                                 continue;
                         if (kdb_bt1(p, mask, argcount, btaprompt))
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 0a69d2adc4f3..14ff4849262c 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -552,6 +552,7 @@ int vkdb_printf(const char *fmt, va_list ap)
 {
         int diag;
         int linecount;
+        int colcount;
         int logging, saved_loglevel = 0;
         int saved_trap_printk;
         int got_printf_lock = 0;
@@ -584,6 +585,10 @@ int vkdb_printf(const char *fmt, va_list ap)
         if (diag || linecount <= 1)
                 linecount = 24;
 
+        diag = kdbgetintenv("COLUMNS", &colcount);
+        if (diag || colcount <= 1)
+                colcount = 80;
+
         diag = kdbgetintenv("LOGGING", &logging);
         if (diag)
                 logging = 0;
@@ -690,7 +695,7 @@ kdb_printit:
                 gdbstub_msg_write(kdb_buffer, retlen);
         } else {
                 if (dbg_io_ops && !dbg_io_ops->is_console) {
-                        len = strlen(kdb_buffer);
+                        len = retlen;
                         cp = kdb_buffer;
                         while (len--) {
                                 dbg_io_ops->write_char(*cp);
@@ -709,11 +714,29 @@ kdb_printit:
                 printk(KERN_INFO "%s", kdb_buffer);
         }
 
-        if (KDB_STATE(PAGER) && strchr(kdb_buffer, '\n'))
-                kdb_nextline++;
+        if (KDB_STATE(PAGER)) {
+                /*
+                 * Check printed string to decide how to bump the
+                 * kdb_nextline to control when the more prompt should
+                 * show up.
+                 */
+                int got = 0;
+                len = retlen;
+                while (len--) {
+                        if (kdb_buffer[len] == '\n') {
+                                kdb_nextline++;
+                                got = 0;
+                        } else if (kdb_buffer[len] == '\r') {
+                                got = 0;
+                        } else {
+                                got++;
+                        }
+                }
+                kdb_nextline += got / (colcount + 1);
+        }
 
         /* check for having reached the LINES number of printed lines */
-        if (kdb_nextline == linecount) {
+        if (kdb_nextline >= linecount) {
                 char buf1[16] = "";
 
                 /* Watch out for recursion here.  Any routine that calls
@@ -765,7 +788,7 @@ kdb_printit:
                         kdb_grepping_flag = 0;
                         kdb_printf("\n");
                 } else if (buf1[0] == ' ') {
-                        kdb_printf("\n");
+                        kdb_printf("\r");
                         suspend_grep = 1; /* for this recursion */
                 } else if (buf1[0] == '\n') {
                         kdb_nextline = linecount - 1;
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 1261dc7eaeb9..4d5f8d5612f3 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -2101,6 +2101,8 @@ static int kdb_dmesg(int argc, const char **argv)
                 }
                 if (!lines--)
                         break;
+                if (KDB_FLAG(CMD_INTERRUPT))
+                        return 0;
 
                 kdb_printf("%.*s\n", (int)len - 1, buf);
         }