Merge tag 'kgdb-fixes-4.20-rc3' of https://git.linaro.org/people/daniel.thompson/linux

Pull kgdb fixes from Daniel Thompson:
 "The most important changes here are two fixes for kdb regressions
  causes by the hashing of %p pointers together with a fix for a
  potential overflow in kdb tab completion handling (and warning fix).

  Also included are a set of changes in preparation to (eventually)
  enable -Wimplicit-fallthrough"

* tag 'kgdb-fixes-4.20-rc3' of https://git.linaro.org/people/daniel.thompson/linux:
  kdb: kdb_support: mark expected switch fall-throughs
  kdb: kdb_keyboard: mark expected switch fall-throughs
  kdb: kdb_main: refactor code in kdb_md_line
  kdb: Use strscpy with destination buffer size
  kdb: print real address of pointers instead of hashed addresses
  kdb: use correct pointer when 'btc' calls 'btt'

kernel/debug/kdb/kdb_bt.c

@@ -179,14 +179,14 @@ kdb_bt(int argc, const char **argv)
 				kdb_printf("no process for cpu %ld\n", cpu);
 				return 0;
 			}
-			sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu));
+			sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu));
 			kdb_parse(buf);
 			return 0;
 		}
 		kdb_printf("btc: cpu status: ");
 		kdb_parse("cpu\n");
 		for_each_online_cpu(cpu) {
-			sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu));
+			sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu));
 			kdb_parse(buf);
 			touch_nmi_watchdog();
 		}

kernel/debug/kdb/kdb_io.c

@@ -216,7 +216,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
 	int count;
 	int i;
 	int diag, dtab_count;
-	int key;
+	int key, buf_size, ret;
 
 
 	diag = kdbgetintenv("DTABCOUNT", &dtab_count);
@@ -336,9 +336,8 @@ static char *kdb_read(char *buffer, size_t bufsize)
 		else
 			p_tmp = tmpbuffer;
 		len = strlen(p_tmp);
-		count = kallsyms_symbol_complete(p_tmp,
-						 sizeof(tmpbuffer) -
-						 (p_tmp - tmpbuffer));
+		buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
+		count = kallsyms_symbol_complete(p_tmp, buf_size);
 		if (tab == 2 && count > 0) {
 			kdb_printf("\n%d symbols are found.", count);
 			if (count > dtab_count) {
@@ -350,9 +349,13 @@ static char *kdb_read(char *buffer, size_t bufsize)
 			}
 			kdb_printf("\n");
 			for (i = 0; i < count; i++) {
-				if (WARN_ON(!kallsyms_symbol_next(p_tmp, i)))
+				ret = kallsyms_symbol_next(p_tmp, i, buf_size);
+				if (WARN_ON(!ret))
 					break;
+				if (ret != -E2BIG)
 					kdb_printf("%s ", p_tmp);
+				else
+					kdb_printf("%s... ", p_tmp);
 				*(p_tmp + len) = '\0';
 			}
 			if (i >= dtab_count)

kernel/debug/kdb/kdb_keyboard.c

@@ -173,11 +173,11 @@ int kdb_get_kbd_char(void)
 	case KT_LATIN:
 		if (isprint(keychar))
 			break;		/* printable characters */
-		/* drop through */
+		/* fall through */
 	case KT_SPEC:
 		if (keychar == K_ENTER)
 			break;
-		/* drop through */
+		/* fall through */
 	default:
 		return -1;	/* ignore unprintables */
 	}

kernel/debug/kdb/kdb_main.c

@@ -1192,7 +1192,7 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
 	if (reason == KDB_REASON_DEBUG) {
 		/* special case below */
 	} else {
-		kdb_printf("\nEntering kdb (current=0x%p, pid %d) ",
+		kdb_printf("\nEntering kdb (current=0x%px, pid %d) ",
 			   kdb_current, kdb_current ? kdb_current->pid : 0);
 #if defined(CONFIG_SMP)
 		kdb_printf("on processor %d ", raw_smp_processor_id());
@@ -1208,7 +1208,7 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
 		 */
 		switch (db_result) {
 		case KDB_DB_BPT:
-			kdb_printf("\nEntering kdb (0x%p, pid %d) ",
+			kdb_printf("\nEntering kdb (0x%px, pid %d) ",
 				   kdb_current, kdb_current->pid);
 #if defined(CONFIG_SMP)
 			kdb_printf("on processor %d ", raw_smp_processor_id());
@@ -1493,6 +1493,7 @@ static void kdb_md_line(const char *fmtstr, unsigned long addr,
 	char cbuf[32];
 	char *c = cbuf;
 	int i;
+	int j;
 	unsigned long word;
 
 	memset(cbuf, '\0', sizeof(cbuf));
@@ -1538,25 +1539,9 @@ static void kdb_md_line(const char *fmtstr, unsigned long addr,
 			wc.word = word;
 #define printable_char(c) \
 	({unsigned char __c = c; isascii(__c) && isprint(__c) ? __c : '.'; })
-			switch (bytesperword) {
-			case 8:
-				*c++ = printable_char(*cp++);
-				*c++ = printable_char(*cp++);
-				*c++ = printable_char(*cp++);
+			for (j = 0; j < bytesperword; j++)
 				*c++ = printable_char(*cp++);
-				addr += 4;
-			case 4:
-				*c++ = printable_char(*cp++);
-				*c++ = printable_char(*cp++);
-				addr += 2;
-			case 2:
-				*c++ = printable_char(*cp++);
-				addr++;
-			case 1:
-				*c++ = printable_char(*cp++);
-				addr++;
-				break;
-			}
+			addr += bytesperword;
 #undef printable_char
 		}
 	}
@@ -2048,7 +2033,7 @@ static int kdb_lsmod(int argc, const char **argv)
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
 
-		kdb_printf("%-20s%8u  0x%p ", mod->name,
+		kdb_printf("%-20s%8u  0x%px ", mod->name,
 			   mod->core_layout.size, (void *)mod);
 #ifdef CONFIG_MODULE_UNLOAD
 		kdb_printf("%4d ", module_refcount(mod));
@@ -2059,7 +2044,7 @@ static int kdb_lsmod(int argc, const char **argv)
 			kdb_printf(" (Loading)");
 		else
 			kdb_printf(" (Live)");
-		kdb_printf(" 0x%p", mod->core_layout.base);
+		kdb_printf(" 0x%px", mod->core_layout.base);
 
 #ifdef CONFIG_MODULE_UNLOAD
 		{
@@ -2341,7 +2326,7 @@ void kdb_ps1(const struct task_struct *p)
 		return;
 
 	cpu = kdb_process_cpu(p);
-	kdb_printf("0x%p %8d %8d  %d %4d   %c  0x%p %c%s\n",
+	kdb_printf("0x%px %8d %8d  %d %4d   %c  0x%px %c%s\n",
 		   (void *)p, p->pid, p->parent->pid,
 		   kdb_task_has_cpu(p), kdb_process_cpu(p),
 		   kdb_task_state_char(p),
@@ -2354,7 +2339,7 @@ void kdb_ps1(const struct task_struct *p)
 		} else {
 			if (KDB_TSK(cpu) != p)
 				kdb_printf("  Error: does not match running "
-				   "process table (0x%p)\n", KDB_TSK(cpu));
+				   "process table (0x%px)\n", KDB_TSK(cpu));
 		}
 	}
 }
@@ -2687,7 +2672,7 @@ int kdb_register_flags(char *cmd,
 	for_each_kdbcmd(kp, i) {
 		if (kp->cmd_name && (strcmp(kp->cmd_name, cmd) == 0)) {
 			kdb_printf("Duplicate kdb command registered: "
-				"%s, func %p help %s\n", cmd, func, help);
+				"%s, func %px help %s\n", cmd, func, help);
 			return 1;
 		}
 	}

kernel/debug/kdb/kdb_private.h

@@ -83,7 +83,7 @@ typedef struct __ksymtab {
 		unsigned long sym_start;
 		unsigned long sym_end;
 		} kdb_symtab_t;
-extern int kallsyms_symbol_next(char *prefix_name, int flag);
+extern int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size);
 extern int kallsyms_symbol_complete(char *prefix_name, int max_len);
 
 /* Exported Symbols for kernel loadable modules to use. */

kernel/debug/kdb/kdb_support.c

@@ -40,7 +40,7 @@
 int kdbgetsymval(const char *symname, kdb_symtab_t *symtab)
 {
 	if (KDB_DEBUG(AR))
-		kdb_printf("kdbgetsymval: symname=%s, symtab=%p\n", symname,
+		kdb_printf("kdbgetsymval: symname=%s, symtab=%px\n", symname,
 			   symtab);
 	memset(symtab, 0, sizeof(*symtab));
 	symtab->sym_start = kallsyms_lookup_name(symname);
@@ -88,7 +88,7 @@ int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
 	char *knt1 = NULL;
 
 	if (KDB_DEBUG(AR))
-		kdb_printf("kdbnearsym: addr=0x%lx, symtab=%p\n", addr, symtab);
+		kdb_printf("kdbnearsym: addr=0x%lx, symtab=%px\n", addr, symtab);
 	memset(symtab, 0, sizeof(*symtab));
 
 	if (addr < 4096)
@@ -149,7 +149,7 @@ int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
 		symtab->mod_name = "kernel";
 	if (KDB_DEBUG(AR))
 		kdb_printf("kdbnearsym: returns %d symtab->sym_start=0x%lx, "
-		   "symtab->mod_name=%p, symtab->sym_name=%p (%s)\n", ret,
+		   "symtab->mod_name=%px, symtab->sym_name=%px (%s)\n", ret,
 		   symtab->sym_start, symtab->mod_name, symtab->sym_name,
 		   symtab->sym_name);
 
@@ -221,11 +221,13 @@ int kallsyms_symbol_complete(char *prefix_name, int max_len)
  * Parameters:
  *	prefix_name	prefix of a symbol name to lookup
  *	flag	0 means search from the head, 1 means continue search.
+ *	buf_size	maximum length that can be written to prefix_name
+ *			buffer
  * Returns:
  *	1 if a symbol matches the given prefix.
  *	0 if no string found
  */
-int kallsyms_symbol_next(char *prefix_name, int flag)
+int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size)
 {
 	int prefix_len = strlen(prefix_name);
 	static loff_t pos;
@@ -235,10 +237,8 @@ int kallsyms_symbol_next(char *prefix_name, int flag)
 		pos = 0;
 
 	while ((name = kdb_walk_kallsyms(&pos))) {
-		if (strncmp(name, prefix_name, prefix_len) == 0) {
-			strncpy(prefix_name, name, strlen(name)+1);
-			return 1;
-		}
+		if (!strncmp(name, prefix_name, prefix_len))
+			return strscpy(prefix_name, name, buf_size);
 	}
 	return 0;
 }
@@ -432,7 +432,7 @@ int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size)
 				*word = w8;
 			break;
 		}
-		/* drop through */
+		/* fall through */
 	default:
 		diag = KDB_BADWIDTH;
 		kdb_printf("kdb_getphysword: bad width %ld\n", (long) size);
@@ -481,7 +481,7 @@ int kdb_getword(unsigned long *word, unsigned long addr, size_t size)
 				*word = w8;
 			break;
 		}
-		/* drop through */
+		/* fall through */
 	default:
 		diag = KDB_BADWIDTH;
 		kdb_printf("kdb_getword: bad width %ld\n", (long) size);
@@ -525,7 +525,7 @@ int kdb_putword(unsigned long addr, unsigned long word, size_t size)
 			diag = kdb_putarea(addr, w8);
 			break;
 		}
-		/* drop through */
+		/* fall through */
 	default:
 		diag = KDB_BADWIDTH;
 		kdb_printf("kdb_putword: bad width %ld\n", (long) size);
@@ -887,13 +887,13 @@ void debug_kusage(void)
 		   __func__, dah_first);
 	if (dah_first) {
 		h_used = (struct debug_alloc_header *)debug_alloc_pool;
-		kdb_printf("%s: h_used %p size %d\n", __func__, h_used,
+		kdb_printf("%s: h_used %px size %d\n", __func__, h_used,
 			   h_used->size);
 	}
 	do {
 		h_used = (struct debug_alloc_header *)
 			  ((char *)h_free + dah_overhead + h_free->size);
-		kdb_printf("%s: h_used %p size %d caller %p\n",
+		kdb_printf("%s: h_used %px size %d caller %px\n",
 			   __func__, h_used, h_used->size, h_used->caller);
 		h_free = (struct debug_alloc_header *)
 			  (debug_alloc_pool + h_free->next);
@@ -902,7 +902,7 @@ void debug_kusage(void)
 		  ((char *)h_free + dah_overhead + h_free->size);
 	if ((char *)h_used - debug_alloc_pool !=
 	    sizeof(debug_alloc_pool_aligned))
-		kdb_printf("%s: h_used %p size %d caller %p\n",
+		kdb_printf("%s: h_used %px size %d caller %px\n",
 			   __func__, h_used, h_used->size, h_used->caller);
 out:
 	spin_unlock(&dap_lock);