1 files changed, 42 insertions, 23 deletions

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 6a77f1c779c4..61c1690058ed 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -334,7 +334,7 @@ poll_again:
 		*cp = '\0';
 		p_tmp = strrchr(buffer, ' ');
 		p_tmp = (p_tmp ? p_tmp + 1 : buffer);
-		strscpy(tmpbuffer, p_tmp, sizeof(tmpbuffer));
+		strscpy(tmpbuffer, p_tmp);
 		*cp = tmp;
 
 		len = strlen(tmpbuffer);
@@ -452,7 +452,7 @@ poll_again:
 char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
 {
 	if (prompt && kdb_prompt_str != prompt)
-		strscpy(kdb_prompt_str, prompt, CMD_BUFLEN);
+		strscpy(kdb_prompt_str, prompt);
 	kdb_printf("%s", kdb_prompt_str);
 	kdb_nextline = 1;	/* Prompt and input resets line number */
 	return kdb_read(buffer, bufsize);
@@ -589,24 +589,41 @@ static void kdb_msg_write(const char *msg, int msg_len)
 	 */
 	cookie = console_srcu_read_lock();
 	for_each_console_srcu(c) {
-		if (!(console_srcu_read_flags(c) & CON_ENABLED))
+		short flags = console_srcu_read_flags(c);
+
+		if (!console_is_usable(c, flags, true))
 			continue;
 		if (c == dbg_io_ops->cons)
 			continue;
-		if (!c->write)
-			continue;
-		/*
-		 * Set oops_in_progress to encourage the console drivers to
-		 * disregard their internal spin locks: in the current calling
-		 * context the risk of deadlock is a bigger problem than risks
-		 * due to re-entering the console driver. We operate directly on
-		 * oops_in_progress rather than using bust_spinlocks() because
-		 * the calls bust_spinlocks() makes on exit are not appropriate
-		 * for this calling context.
-		 */
-		++oops_in_progress;
-		c->write(c, msg, msg_len);
-		--oops_in_progress;
+
+		if (flags & CON_NBCON) {
+			struct nbcon_write_context wctxt = { };
+
+			/*
+			 * Do not continue if the console is NBCON and the context
+			 * can't be acquired.
+			 */
+			if (!nbcon_kdb_try_acquire(c, &wctxt))
+				continue;
+
+			nbcon_write_context_set_buf(&wctxt, (char *)msg, msg_len);
+
+			c->write_atomic(c, &wctxt);
+			nbcon_kdb_release(&wctxt);
+		} else {
+			/*
+			 * Set oops_in_progress to encourage the console drivers to
+			 * disregard their internal spin locks: in the current calling
+			 * context the risk of deadlock is a bigger problem than risks
+			 * due to re-entering the console driver. We operate directly on
+			 * oops_in_progress rather than using bust_spinlocks() because
+			 * the calls bust_spinlocks() makes on exit are not appropriate
+			 * for this calling context.
+			 */
+			++oops_in_progress;
+			c->write(c, msg, msg_len);
+			--oops_in_progress;
+		}
 		touch_nmi_watchdog();
 	}
 	console_srcu_read_unlock(cookie);
@@ -714,8 +731,8 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
 		 * it, depending on the results of the search.
 		 */
 		cp++;	 	     /* to byte after the newline */
-		replaced_byte = *cp; /* remember what/where it was */
-		cphold = cp;
+		replaced_byte = *cp; /* remember what it was */
+		cphold = cp;	     /* remember where it was */
 		*cp = '\0';	     /* end the string for our search */
 
 		/*
@@ -732,8 +749,9 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
 			 * Shift the buffer left.
 			 */
 			*cphold = replaced_byte;
-			strcpy(kdb_buffer, cphold);
-			len = strlen(kdb_buffer);
+			len = strlen(cphold);
+			/* Use memmove() because the buffers overlap */
+			memmove(kdb_buffer, cphold, len + 1);
 			next_avail = kdb_buffer + len;
 			size_avail = sizeof(kdb_buffer) - len;
 			goto kdb_print_out;
@@ -872,8 +890,9 @@ kdb_printit:
 	 */
 	if (kdb_grepping_flag && !suspend_grep) {
 		*cphold = replaced_byte;
-		strcpy(kdb_buffer, cphold);
-		len = strlen(kdb_buffer);
+		len = strlen(cphold);
+		/* Use memmove() because the buffers overlap */
+		memmove(kdb_buffer, cphold, len + 1);
 		next_avail = kdb_buffer + len;
 		size_avail = sizeof(kdb_buffer) - len;
 	}