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.
          */
         retlen = strlen(kdb_buffer);
+        cp = (char *) printk_skip_level(kdb_buffer);
         if (!dbg_kdb_mode && kgdb_connected) {
-                gdbstub_msg_write(kdb_buffer, retlen);
+                gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
         } else {
                 if (dbg_io_ops && !dbg_io_ops->is_console) {
-                        len = retlen;
-                        cp = kdb_buffer;
+                        len = retlen - (cp - kdb_buffer);
+                        cp2 = cp;
                         while (len--) {
-                                dbg_io_ops->write_char(*cp);
-                                cp++;
+                                dbg_io_ops->write_char(*cp2);
+                                cp2++;
                         }
                 }
                 while (c) {
-                        c->write(c, kdb_buffer, retlen);
+                        c->write(c, cp, retlen - (cp - kdb_buffer));
                         touch_nmi_watchdog();
                         c = c->next;
                 }
@@ -711,7 +718,10 @@ kdb_printit:
         if (logging) {
                 saved_loglevel = console_loglevel;
                 console_loglevel = CONSOLE_LOGLEVEL_SILENT;
-                printk(KERN_INFO "%s", kdb_buffer);
+                if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
+                        printk("%s", kdb_buffer);
+                else
+                        pr_info("%s", kdb_buffer);
         }
 
         if (KDB_STATE(PAGER)) {
@@ -794,11 +804,23 @@ kdb_printit:
                         kdb_nextline = linecount - 1;
                         kdb_printf("\r");
                         suspend_grep = 1; /* for this recursion */
+                } else if (buf1[0] == '/' && !kdb_grepping_flag) {
+                        kdb_printf("\r");
+                        kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
+                                   kdbgetenv("SEARCHPROMPT") ?: "search> ");
+                        *strchrnul(kdb_grep_string, '\n') = '\0';
+                        kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
+                        suspend_grep = 1; /* for this recursion */
                 } else if (buf1[0] && buf1[0] != '\n') {
                         /* user hit something other than enter */
                         suspend_grep = 1; /* for this recursion */
-                        kdb_printf("\nOnly 'q' or 'Q' are processed at more "
-                                   "prompt, input ignored\n");
+                        if (buf1[0] != '/')
+                                kdb_printf(
+                                    "\nOnly 'q', 'Q' or '/' are processed at "
+                                    "more prompt, input ignored\n");
+                        else
+                                kdb_printf("\n'/' cannot be used during | "
+                                           "grep filtering, input ignored\n");
                 } else if (kdb_grepping_flag) {
                         /* user hit enter */
                         suspend_grep = 1; /* for this recursion */
@@ -844,7 +866,7 @@ int kdb_printf(const char *fmt, ...)
         int r;
 
         va_start(ap, fmt);
-        r = vkdb_printf(fmt, ap);
+        r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
         va_end(ap);
 
         return r;
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 7b40c5f07dce..4121345498e0 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -50,8 +50,7 @@
 static int kdb_cmd_enabled = CONFIG_KDB_DEFAULT_ENABLE;
 module_param_named(cmd_enable, kdb_cmd_enabled, int, 0600);
 
-#define GREP_LEN 256
-char kdb_grep_string[GREP_LEN];
+char kdb_grep_string[KDB_GREP_STRLEN];
 int kdb_grepping_flag;
 EXPORT_SYMBOL(kdb_grepping_flag);
 int kdb_grep_leading;
@@ -870,7 +869,7 @@ static void parse_grep(const char *str)
         len = strlen(cp);
         if (!len)
                 return;
-        if (len >= GREP_LEN) {
+        if (len >= KDB_GREP_STRLEN) {
                 kdb_printf("search string too long\n");
                 return;
         }
@@ -915,13 +914,12 @@ int kdb_parse(const char *cmdstr)
         char *cp;
         char *cpp, quoted;
         kdbtab_t *tp;
-        int i, escaped, ignore_errors = 0, check_grep;
+        int i, escaped, ignore_errors = 0, check_grep = 0;
 
         /*
          * First tokenize the command string.
          */
         cp = (char *)cmdstr;
-        kdb_grepping_flag = check_grep = 0;
 
         if (KDB_FLAG(CMD_INTERRUPT)) {
                 /* Previous command was interrupted, newline must not
@@ -1247,7 +1245,6 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
                 kdb_printf("due to NonMaskable Interrupt @ "
                            kdb_machreg_fmt "\n",
                            instruction_pointer(regs));
-                kdb_dumpregs(regs);
                 break;
         case KDB_REASON_SSTEP:
         case KDB_REASON_BREAK:
@@ -1281,6 +1278,9 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
                  */
                 kdb_nextline = 1;
                 KDB_STATE_CLEAR(SUPPRESS);
+                kdb_grepping_flag = 0;
+                /* ensure the old search does not leak into '/' commands */
+                kdb_grep_string[0] = '\0';
 
                 cmdbuf = cmd_cur;
                 *cmdbuf = '\0';
@@ -2256,7 +2256,7 @@ static int kdb_cpu(int argc, const char **argv)
         /*
          * Validate cpunum
          */
-        if ((cpunum > NR_CPUS) || !kgdb_info[cpunum].enter_kgdb)
+        if ((cpunum >= CONFIG_NR_CPUS) || !kgdb_info[cpunum].enter_kgdb)
                 return KDB_BADCPUNUM;
 
         dbg_switch_cpu = cpunum;
@@ -2583,7 +2583,7 @@ static int kdb_summary(int argc, const char **argv)
 #define K(x) ((x) << (PAGE_SHIFT - 10))
         kdb_printf("\nMemTotal:       %8lu kB\nMemFree:        %8lu kB\n"
                    "Buffers:        %8lu kB\n",
-                   val.totalram, val.freeram, val.bufferram);
+                   K(val.totalram), K(val.freeram), K(val.bufferram));
         return 0;
 }
 
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index eaacd1693954..75014d7f4568 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -196,7 +196,9 @@ extern int kdb_main_loop(kdb_reason_t, kdb_reason_t,
 
 /* Miscellaneous functions and data areas */
 extern int kdb_grepping_flag;
+#define KDB_GREPPING_FLAG_SEARCH 0x8000
 extern char kdb_grep_string[];
+#define KDB_GREP_STRLEN 256
 extern int kdb_grep_leading;
 extern int kdb_grep_trailing;
 extern char *kdb_cmds[];
@@ -209,7 +211,7 @@ extern void kdb_ps1(const struct task_struct *p);
 extern void kdb_print_nameval(const char *name, unsigned long val);
 extern void kdb_send_sig_info(struct task_struct *p, struct siginfo *info);
 extern void kdb_meminfo_proc_show(void);
-extern char *kdb_getstr(char *, size_t, char *);
+extern char *kdb_getstr(char *, size_t, const char *);
 extern void kdb_gdb_state_pass(char *buf);
 
 /* Defines for kdb_symbol_print */
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index c06df7de0963..01cfd69c54c6 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1811,7 +1811,7 @@ int vprintk_default(const char *fmt, va_list args)
 
 #ifdef CONFIG_KGDB_KDB
         if (unlikely(kdb_trap_printk)) {
-                r = vkdb_printf(fmt, args);
+                r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args);
                 return r;
         }
 #endif