Merge tag 'for_linux-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

Pull KGDB/KDB fixes and cleanups from Jason Wessel:
 "For a change we removed more code than we added.  If people aren't
  using it we shouldn't be carrying it.  :-)

  Cleanups:
   - Remove kdb ssb command - there is no in kernel disassembler to
     support it

   - Remove kdb ll command - Always caused a kernel oops and there were
     no bug reports so no one was using this command

   - Use kernel ARRAY_SIZE macro instead of array computations

  Fixes:
   - Stop oops in kdb if user executes kdb_defcmd with args

   - kdb help command truncated text

   - ppc64 support for kgdbts

   - Add missing kconfig option from original kdb port for dealing with
     catastrophic kernel crashes such that you can reboot automatically
     on continue from kdb"

* tag 'for_linux-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  kdb: Remove unhandled ssb command
  kdb: Prevent kernel oops with kdb_defcmd
  kdb: Remove the ll command
  kdb_main: fix help print
  kdb: Fix overlap in buffers with strcpy
  Fixed dead ifdef block by adding missing Kconfig option.
  kdb: Setup basic kdb state before invoking commands via kgdb
  kdb: use ARRAY_SIZE where possible
  kgdb/kgdbts: support ppc64
  kdb: A fix for kdb command table expansion

drivers/misc/kgdbts.c

@@ -103,6 +103,7 @@
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
+#include <asm/sections.h>
 
 #define v1printk(a...) do { \
 	if (verbose) \
@@ -222,6 +223,7 @@ static unsigned long lookup_addr(char *arg)
 		addr = (unsigned long)do_fork;
 	else if (!strcmp(arg, "hw_break_val"))
 		addr = (unsigned long)&hw_break_val;
+	addr = (unsigned long) dereference_function_descriptor((void *)addr);
 	return addr;
 }
 

kernel/debug/debug_core.h

@@ -72,6 +72,8 @@ extern int dbg_kdb_mode;
 #ifdef CONFIG_KGDB_KDB
 extern int kdb_stub(struct kgdb_state *ks);
 extern int kdb_parse(const char *cmdstr);
+extern int kdb_common_init_state(struct kgdb_state *ks);
+extern int kdb_common_deinit_state(void);
 #else /* ! CONFIG_KGDB_KDB */
 static inline int kdb_stub(struct kgdb_state *ks)
 {

kernel/debug/gdbstub.c

@@ -783,7 +783,10 @@ static void gdb_cmd_query(struct kgdb_state *ks)
 			len = len / 2;
 			remcom_out_buffer[len++] = 0;
 
+			kdb_common_init_state(ks);
 			kdb_parse(remcom_out_buffer);
+			kdb_common_deinit_state();
+
 			strcpy(remcom_out_buffer, "OK");
 		}
 		break;

kernel/debug/kdb/kdb_bp.c

@@ -486,11 +486,9 @@ static int kdb_bc(int argc, const char **argv)
 /*
  * kdb_ss
  *
- *	Process the 'ss' (Single Step) and 'ssb' (Single Step to Branch)
- *	commands.
+ *	Process the 'ss' (Single Step) command.
  *
  *	ss
- *	ssb
  *
  * Parameters:
  *	argc	Argument count
@@ -498,35 +496,23 @@ static int kdb_bc(int argc, const char **argv)
  * Outputs:
  *	None.
  * Returns:
- *	KDB_CMD_SS[B] for success, a kdb error if failure.
+ *	KDB_CMD_SS for success, a kdb error if failure.
  * Locking:
  *	None.
  * Remarks:
  *
  *	Set the arch specific option to trigger a debug trap after the next
  *	instruction.
- *
- *	For 'ssb', set the trace flag in the debug trap handler
- *	after printing the current insn and return directly without
- *	invoking the kdb command processor, until a branch instruction
- *	is encountered.
  */
 
 static int kdb_ss(int argc, const char **argv)
 {
-	int ssb = 0;
-
-	ssb = (strcmp(argv[0], "ssb") == 0);
 	if (argc != 0)
 		return KDB_ARGCOUNT;
 	/*
 	 * Set trace flag and go.
 	 */
 	KDB_STATE_SET(DOING_SS);
-	if (ssb) {
-		KDB_STATE_SET(DOING_SSB);
-		return KDB_CMD_SSB;
-	}
 	return KDB_CMD_SS;
 }
 
@@ -561,8 +547,6 @@ void __init kdb_initbptab(void)
 
 	kdb_register_repeat("ss", kdb_ss, "",
 		"Single Step", 1, KDB_REPEAT_NO_ARGS);
-	kdb_register_repeat("ssb", kdb_ss, "",
-		"Single step to branch/call", 0, KDB_REPEAT_NO_ARGS);
 	/*
 	 * Architecture dependent initialization.
 	 */

kernel/debug/kdb/kdb_debugger.c

@@ -34,6 +34,22 @@ EXPORT_SYMBOL_GPL(kdb_poll_idx);
 
 static struct kgdb_state *kdb_ks;
 
+int kdb_common_init_state(struct kgdb_state *ks)
+{
+	kdb_initial_cpu = atomic_read(&kgdb_active);
+	kdb_current_task = kgdb_info[ks->cpu].task;
+	kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
+	return 0;
+}
+
+int kdb_common_deinit_state(void)
+{
+	kdb_initial_cpu = -1;
+	kdb_current_task = NULL;
+	kdb_current_regs = NULL;
+	return 0;
+}
+
 int kdb_stub(struct kgdb_state *ks)
 {
 	int error = 0;
@@ -94,13 +110,10 @@ int kdb_stub(struct kgdb_state *ks)
 	}
 	/* Set initial kdb state variables */
 	KDB_STATE_CLEAR(KGDB_TRANS);
-	kdb_initial_cpu = atomic_read(&kgdb_active);
-	kdb_current_task = kgdb_info[ks->cpu].task;
-	kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
+	kdb_common_init_state(ks);
 	/* Remove any breakpoints as needed by kdb and clear single step */
 	kdb_bp_remove();
 	KDB_STATE_CLEAR(DOING_SS);
-	KDB_STATE_CLEAR(DOING_SSB);
 	KDB_STATE_SET(PAGER);
 	/* zero out any offline cpu data */
 	for_each_present_cpu(i) {
@@ -125,9 +138,7 @@ int kdb_stub(struct kgdb_state *ks)
 	 * Upon exit from the kdb main loop setup break points and restart
 	 * the system based on the requested continue state
 	 */
-	kdb_initial_cpu = -1;
-	kdb_current_task = NULL;
-	kdb_current_regs = NULL;
+	kdb_common_deinit_state();
 	KDB_STATE_CLEAR(PAGER);
 	kdbnearsym_cleanup();
 	if (error == KDB_CMD_KGDB) {

kernel/debug/kdb/kdb_main.c

@@ -124,7 +124,7 @@ static kdbmsg_t kdbmsgs[] = {
 };
 #undef KDBMSG
 
-static const int __nkdb_err = sizeof(kdbmsgs) / sizeof(kdbmsg_t);
+static const int __nkdb_err = ARRAY_SIZE(kdbmsgs);
 
 
 /*
@@ -175,7 +175,7 @@ static char *__env[] = {
  (char *)0,
 };
 
-static const int __nenv = (sizeof(__env) / sizeof(char *));
+static const int __nenv = ARRAY_SIZE(__env);
 
 struct task_struct *kdb_curr_task(int cpu)
 {
@@ -681,34 +681,50 @@ static int kdb_defcmd(int argc, const char **argv)
 	}
 	if (argc != 3)
 		return KDB_ARGCOUNT;
-	defcmd_set = kmalloc((defcmd_set_count + 1) * sizeof(*defcmd_set),
-			     GFP_KDB);
-	if (!defcmd_set) {
-		kdb_printf("Could not allocate new defcmd_set entry for %s\n",
-			   argv[1]);
-		defcmd_set = save_defcmd_set;
+	if (in_dbg_master()) {
+		kdb_printf("Command only available during kdb_init()\n");
 		return KDB_NOTIMP;
 	}
+	defcmd_set = kmalloc((defcmd_set_count + 1) * sizeof(*defcmd_set),
+			     GFP_KDB);
+	if (!defcmd_set)
+		goto fail_defcmd;
 	memcpy(defcmd_set, save_defcmd_set,
 	       defcmd_set_count * sizeof(*defcmd_set));
-	kfree(save_defcmd_set);
 	s = defcmd_set + defcmd_set_count;
 	memset(s, 0, sizeof(*s));
 	s->usable = 1;
 	s->name = kdb_strdup(argv[1], GFP_KDB);
+	if (!s->name)
+		goto fail_name;
 	s->usage = kdb_strdup(argv[2], GFP_KDB);
+	if (!s->usage)
+		goto fail_usage;
 	s->help = kdb_strdup(argv[3], GFP_KDB);
+	if (!s->help)
+		goto fail_help;
 	if (s->usage[0] == '"') {
-		strcpy(s->usage, s->usage+1);
+		strcpy(s->usage, argv[2]+1);
 		s->usage[strlen(s->usage)-1] = '\0';
 	}
 	if (s->help[0] == '"') {
-		strcpy(s->help, s->help+1);
+		strcpy(s->help, argv[3]+1);
 		s->help[strlen(s->help)-1] = '\0';
 	}
 	++defcmd_set_count;
 	defcmd_in_progress = 1;
+	kfree(save_defcmd_set);
 	return 0;
+fail_help:
+	kfree(s->usage);
+fail_usage:
+	kfree(s->name);
+fail_name:
+	kfree(defcmd_set);
+fail_defcmd:
+	kdb_printf("Could not allocate new defcmd_set entry for %s\n", argv[1]);
+	defcmd_set = save_defcmd_set;
+	return KDB_NOTIMP;
 }
 
 /*
@@ -1112,7 +1128,6 @@ void kdb_set_current_task(struct task_struct *p)
  *	KDB_CMD_GO	User typed 'go'.
  *	KDB_CMD_CPU	User switched to another cpu.
  *	KDB_CMD_SS	Single step.
- *	KDB_CMD_SSB	Single step until branch.
  */
 static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
 		     kdb_dbtrap_t db_result)
@@ -1151,14 +1166,6 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
 			kdb_printf("due to Debug @ " kdb_machreg_fmt "\n",
 				   instruction_pointer(regs));
 			break;
-		case KDB_DB_SSB:
-			/*
-			 * In the midst of ssb command. Just return.
-			 */
-			KDB_DEBUG_STATE("kdb_local 3", reason);
-			return KDB_CMD_SSB;	/* Continue with SSB command */
-
-			break;
 		case KDB_DB_SS:
 			break;
 		case KDB_DB_SSBPT:
@@ -1281,7 +1288,6 @@ do_full_getstr:
 		if (diag == KDB_CMD_GO
 		 || diag == KDB_CMD_CPU
 		 || diag == KDB_CMD_SS
-		 || diag == KDB_CMD_SSB
 		 || diag == KDB_CMD_KGDB)
 			break;
 
@@ -1368,12 +1374,6 @@ int kdb_main_loop(kdb_reason_t reason, kdb_reason_t reason2, int error,
 			break;
 		}
 
-		if (result == KDB_CMD_SSB) {
-			KDB_STATE_SET(DOING_SS);
-			KDB_STATE_SET(DOING_SSB);
-			break;
-		}
-
 		if (result == KDB_CMD_KGDB) {
 			if (!KDB_STATE(DOING_KGDB))
 				kdb_printf("Entering please attach debugger "
@@ -2350,69 +2350,6 @@ static int kdb_pid(int argc, const char **argv)
 	return 0;
 }
 
-/*
- * kdb_ll - This function implements the 'll' command which follows a
- *	linked list and executes an arbitrary command for each
- *	element.
- */
-static int kdb_ll(int argc, const char **argv)
-{
-	int diag = 0;
-	unsigned long addr;
-	long offset = 0;
-	unsigned long va;
-	unsigned long linkoffset;
-	int nextarg;
-	const char *command;
-
-	if (argc != 3)
-		return KDB_ARGCOUNT;
-
-	nextarg = 1;
-	diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, &offset, NULL);
-	if (diag)
-		return diag;
-
-	diag = kdbgetularg(argv[2], &linkoffset);
-	if (diag)
-		return diag;
-
-	/*
-	 * Using the starting address as
-	 * the first element in the list, and assuming that
-	 * the list ends with a null pointer.
-	 */
-
-	va = addr;
-	command = kdb_strdup(argv[3], GFP_KDB);
-	if (!command) {
-		kdb_printf("%s: cannot duplicate command\n", __func__);
-		return 0;
-	}
-	/* Recursive use of kdb_parse, do not use argv after this point */
-	argv = NULL;
-
-	while (va) {
-		char buf[80];
-
-		if (KDB_FLAG(CMD_INTERRUPT))
-			goto out;
-
-		sprintf(buf, "%s " kdb_machreg_fmt "\n", command, va);
-		diag = kdb_parse(buf);
-		if (diag)
-			goto out;
-
-		addr = va + linkoffset;
-		if (kdb_getword(&va, addr, sizeof(va)))
-			goto out;
-	}
-
-out:
-	kfree(command);
-	return diag;
-}
-
 static int kdb_kgdb(int argc, const char **argv)
 {
 	return KDB_CMD_KGDB;
@@ -2430,11 +2367,15 @@ static int kdb_help(int argc, const char **argv)
 	kdb_printf("-----------------------------"
 		   "-----------------------------\n");
 	for_each_kdbcmd(kt, i) {
-		if (kt->cmd_name)
-			kdb_printf("%-15.15s %-20.20s %s\n", kt->cmd_name,
-				   kt->cmd_usage, kt->cmd_help);
+		char *space = "";
 		if (KDB_FLAG(CMD_INTERRUPT))
 			return 0;
+		if (!kt->cmd_name)
+			continue;
+		if (strlen(kt->cmd_usage) > 20)
+			space = "\n                                    ";
+		kdb_printf("%-15.15s %-20s%s%s\n", kt->cmd_name,
+			   kt->cmd_usage, space, kt->cmd_help);
 	}
 	return 0;
 }
@@ -2739,7 +2680,7 @@ int kdb_register_repeat(char *cmd,
 			  (kdb_max_commands - KDB_BASE_CMD_MAX) * sizeof(*new));
 			kfree(kdb_commands);
 		}
-		memset(new + kdb_max_commands, 0,
+		memset(new + kdb_max_commands - KDB_BASE_CMD_MAX, 0,
 		       kdb_command_extend * sizeof(*new));
 		kdb_commands = new;
 		kp = kdb_commands + kdb_max_commands - KDB_BASE_CMD_MAX;
@@ -2843,15 +2784,13 @@ static void __init kdb_inittab(void)
 	  "Stack traceback", 1, KDB_REPEAT_NONE);
 	kdb_register_repeat("btp", kdb_bt, "<pid>",
 	  "Display stack for process <pid>", 0, KDB_REPEAT_NONE);
-	kdb_register_repeat("bta", kdb_bt, "[DRSTCZEUIMA]",
-	  "Display stack all processes", 0, KDB_REPEAT_NONE);
+	kdb_register_repeat("bta", kdb_bt, "[D|R|S|T|C|Z|E|U|I|M|A]",
+	  "Backtrace all processes matching state flag", 0, KDB_REPEAT_NONE);
 	kdb_register_repeat("btc", kdb_bt, "",
 	  "Backtrace current process on each cpu", 0, KDB_REPEAT_NONE);
 	kdb_register_repeat("btt", kdb_bt, "<vaddr>",
 	  "Backtrace process given its struct task address", 0,
 			    KDB_REPEAT_NONE);
-	kdb_register_repeat("ll", kdb_ll, "<first-element> <linkoffset> <cmd>",
-	  "Execute cmd for each element in linked list", 0, KDB_REPEAT_NONE);
 	kdb_register_repeat("env", kdb_env, "",
 	  "Show environment variables", 0, KDB_REPEAT_NONE);
 	kdb_register_repeat("set", kdb_set, "",

kernel/debug/kdb/kdb_private.h

@@ -19,7 +19,6 @@
 #define KDB_CMD_GO	(-1001)
 #define KDB_CMD_CPU	(-1002)
 #define KDB_CMD_SS	(-1003)
-#define KDB_CMD_SSB	(-1004)
 #define KDB_CMD_KGDB (-1005)
 
 /* Internal debug flags */
@@ -125,8 +124,6 @@ extern int kdb_state;
 						 * kdb control */
 #define KDB_STATE_HOLD_CPU	0x00000010	/* Hold this cpu inside kdb */
 #define KDB_STATE_DOING_SS	0x00000020	/* Doing ss command */
-#define KDB_STATE_DOING_SSB	0x00000040	/* Doing ssb command,
-						 * DOING_SS is also set */
 #define KDB_STATE_SSBPT		0x00000080	/* Install breakpoint
 						 * after one ss, independent of
 						 * DOING_SS */
@@ -191,7 +188,6 @@ extern void kdb_bp_remove(void);
 typedef enum {
 	KDB_DB_BPT,	/* Breakpoint */
 	KDB_DB_SS,	/* Single-step trap */
-	KDB_DB_SSB,	/* Single step to branch */
 	KDB_DB_SSBPT,	/* Single step over breakpoint */
 	KDB_DB_NOBPT	/* Spurious breakpoint */
 } kdb_dbtrap_t;

lib/Kconfig.kgdb

@@ -80,4 +80,22 @@ config KDB_KEYBOARD
 	help
 	  KDB can use a PS/2 type keyboard for an input device
 
+config KDB_CONTINUE_CATASTROPHIC
+	int "KDB: continue after catastrophic errors"
+	depends on KGDB_KDB
+	default "0"
+	help
+	  This integer controls the behaviour of kdb when the kernel gets a
+	  catastrophic error, i.e. for a panic or oops.
+	  When KDB is active and a catastrophic error occurs, nothing extra
+	  will happen until you type 'go'.
+	  CONFIG_KDB_CONTINUE_CATASTROPHIC == 0 (default). The first time
+	  you type 'go', you will be warned by kdb. The secend time you type
+	  'go', KDB tries to continue. No guarantees that the
+	  kernel is still usable in this situation.
+	  CONFIG_KDB_CONTINUE_CATASTROPHIC == 1. KDB tries to continue.
+	  No guarantees that the kernel is still usable in this situation.
+	  CONFIG_KDB_CONTINUE_CATASTROPHIC == 2. KDB forces a reboot.
+	  If you are not sure, say 0.
+
 endif # KGDB