Merge tag 'for_linux-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

Pull kgdb/kdb updates from Jason Wessel:
 "KGDB/KDB New:
   - KDB: improved searching
   - No longer enter debug core on panic if panic timeout is set

  KGDB/KDB regressions / cleanups
   - fix pdf doc build errors
   - prevent junk characters on kdb console from printk levels"

* tag 'for_linux-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  kgdb, docs: Fix <para> pdfdocs build errors
  debug: prevent entering debug mode on panic/exception.
  kdb: Const qualifier for kdb_getstr's prompt argument
  kdb: Provide forward search at more prompt
  kdb: Fix a prompt management bug when using | grep
  kdb: Remove stack dump when entering kgdb due to NMI
  kdb: Avoid printing KERN_ levels to consoles
  kdb: Fix off by one error in kdb_cpu()
  kdb: fix incorrect counts in KDB summary command output

7 files changed, 74 insertions, 27 deletions

diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl
index 2428cc04dbc8..f3abca7ec53d 100644
--- a/Documentation/DocBook/kgdb.tmpl
+++ b/Documentation/DocBook/kgdb.tmpl
@@ -197,6 +197,7 @@
    may be configured as a kernel built-in or a kernel loadable module.
    You can only make use of <constant>kgdbwait</constant> and early
    debugging if you build kgdboc into the kernel as a built-in.
+   </para>
    <para>Optionally you can elect to activate kms (Kernel Mode
    Setting) integration.  When you use kms with kgdboc and you have a
    video driver that has atomic mode setting hooks, it is possible to
@@ -206,7 +207,6 @@
    crashes or doing analysis of memory with kdb while allowing the
    full graphics console applications to run.
    </para>
-   </para>
    <sect2 id="kgdbocArgs">
    <title>kgdboc arguments</title>
    <para>Usage: <constant>kgdboc=[kms][[,]kbd][[,]serial_device][,baud]</constant></para>
@@ -284,7 +284,6 @@
    </listitem>
    </orderedlist>
    </para>
-   </sect3>
    <para>NOTE: Kgdboc does not support interrupting the target via the
    gdb remote protocol.  You must manually send a sysrq-g unless you
    have a proxy that splits console output to a terminal program.
@@ -305,6 +304,7 @@
     as well as on the initial connect, or to use a debugger proxy that
     allows an unmodified gdb to do the debugging.
    </para>
+   </sect3>
    </sect2>
    </sect1>
    <sect1 id="kgdbwait">
@@ -350,12 +350,12 @@
    </para>
    </listitem>
    </orderedlist>
+  </para>
    <para>IMPORTANT NOTE: You cannot use kgdboc + kgdbcon on a tty that is an
    active system console.  An example of incorrect usage is <constant>console=ttyS0,115200 kgdboc=ttyS0 kgdbcon</constant>
    </para>
    <para>It is possible to use this option with kgdboc on a tty that is not a system console.
    </para>
-  </para>
   </sect1>
    <sect1 id="kgdbreboot">
    <title>Run time parameter: kgdbreboot</title>
diff --git a/include/linux/kdb.h b/include/linux/kdb.h
index 75ae2e2631fc..a19bcf9e762e 100644
--- a/include/linux/kdb.h
+++ b/include/linux/kdb.h
@@ -156,8 +156,14 @@ typedef enum {
         KDB_REASON_SYSTEM_NMI,  /* In NMI due to SYSTEM cmd; regs valid */
 } kdb_reason_t;
 
+enum kdb_msgsrc {
+        KDB_MSGSRC_INTERNAL, /* direct call to kdb_printf() */
+        KDB_MSGSRC_PRINTK, /* trapped from printk() */
+};
+
 extern int kdb_trap_printk;
-extern __printf(1, 0) int vkdb_printf(const char *fmt, va_list args);
+extern __printf(2, 0) int vkdb_printf(enum kdb_msgsrc src, const char *fmt,
+                                      va_list args);
 extern __printf(1, 2) int kdb_printf(const char *, ...);
 typedef __printf(1, 2) int (*kdb_printf_t)(const char *, ...);
 
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 07ce18ca71e0..0874e2edd275 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -604,7 +604,7 @@ return_normal:
                    online_cpus)
                 cpu_relax();
         if (!time_left)
-                pr_crit("KGDB: Timed out waiting for secondary CPUs.\n");
+                pr_crit("Timed out waiting for secondary CPUs.\n");
 
         /*
          * At this point the primary processor is completely
@@ -696,6 +696,14 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
 
         if (arch_kgdb_ops.enable_nmi)
                 arch_kgdb_ops.enable_nmi(0);
+        /*
+         * Avoid entering the debugger if we were triggered due to an oops
+         * but panic_timeout indicates the system should automatically
+         * reboot on panic. We don't want to get stuck waiting for input
+         * on such systems, especially if its "just" an oops.
+         */
+        if (signo != SIGTRAP && panic_timeout)
+                return 1;
 
         memset(ks, 0, sizeof(struct kgdb_state));
         ks->cpu                 = raw_smp_processor_id();
@@ -828,6 +836,15 @@ static int kgdb_panic_event(struct notifier_block *self,
                             unsigned long val,
                             void *data)
 {
+        /*
+         * Avoid entering the debugger if we were triggered due to a panic
+         * We don't want to get stuck waiting for input from user in such case.
+         * panic_timeout indicates the system should automatically
+         * reboot on panic.
+         */
+        if (panic_timeout)
+                return NOTIFY_DONE;
+
         if (dbg_kdb_mode)
                 kdb_printf("PANIC: %s\n", (char *)data);
         kgdb_breakpoint();
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 7c70812caea5..fc1ef736253c 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -439,7 +439,7 @@ poll_again:
  *      substituted for %d, %x or %o in the prompt.
  */
 
-char *kdb_getstr(char *buffer, size_t bufsize, char *prompt)
+char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
 {
         if (prompt && kdb_prompt_str != prompt)
                 strncpy(kdb_prompt_str, prompt, CMD_BUFLEN);
@@ -548,7 +548,7 @@ static int kdb_search_string(char *searched, char *searchfor)
         return 0;
 }
 
-int vkdb_printf(const char *fmt, va_list ap)
+int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
 {
         int diag;
         int linecount;
@@ -680,6 +680,12 @@ int vkdb_printf(const char *fmt, va_list ap)
                         size_avail = sizeof(kdb_buffer) - len;
                         goto kdb_print_out;
                 }
+                if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH)
+                        /*
+                         * This was a interactive search (using '/' at more
+                         * prompt) and it has completed. Clear the flag.
+                         */
+                        kdb_grepping_flag = 0;
                 /*
                  * at this point the string is a full line and
                  * should be printed, up to the null.
@@ -691,19 +697,20 @@ kdb_printit:
          * Write to all consoles.
          */