This fixes a regression when a console option includes ':'. Commit
7640f1a44eba ("printk: Add match_devname_and_update_preferred_console()")
introduced console=DEVNAME:0.0 hardware style addressing by looking for a
colon. If the colon is part of an option the name is handled as devname
instead of ttyname.

Fix by handling the options first which will add a NULL terminator to the
string and refactor idx handling to clean up the code (thanks to Petr
Mladek).

Signed-off-by: David Engraf <david.engraf@sysgo.com>
---
 kernel/printk/printk.c | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 6d3d18a50da74..2cbb84effb619 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2646,24 +2646,25 @@ static int __init console_setup(char *str)
 	if (_braille_console_setup(&str, &brl_options))
 		return 1;
 
+	/*
+	 * Decode str into name, index and options. Start with options, since
+	 * it might also contain a ':' used for DEVNAME.
+	 */
+	options = strchr(str, ',');
+	if (options)
+		*(options++) = 0;
+
 	/* For a DEVNAME:0.0 style console the character device is unknown early */
 	if (strchr(str, ':'))
 		devname = buf;
 	else
 		ttyname = buf;
 
-	/*
-	 * Decode str into name, index, options.
-	 */
 	if (ttyname && isdigit(str[0]))
 		scnprintf(buf, sizeof(buf), "ttyS%s", str);
 	else
 		strscpy(buf, str);
 
-	options = strchr(str, ',');
-	if (options)
-		*(options++) = 0;
-
 #ifdef __sparc__
 	if (!strcmp(str, "ttya"))
 		strscpy(buf, "ttyS0");
@@ -2671,17 +2672,18 @@ static int __init console_setup(char *str)
 		strscpy(buf, "ttyS1");
 #endif
 
-	for (s = buf; *s; s++)
-		if ((ttyname && isdigit(*s)) || *s == ',')
-			break;
-
-	/* @idx will get defined when devname matches. */
-	if (devname)
-		idx = -1;
-	else
+	if (ttyname) {
+		/* Detect @idx in ttyname and remove it. */
+		for (s = ttyname; *s; s++) {
+			if (isdigit(*s))
+				break;
+		}
 		idx = simple_strtoul(s, NULL, 10);
-
-	*s = 0;
+		*s = 0;
+	} else {
+		/* @idx will get defined when devname matches. */
+		idx = -1;
+	}
 
 	__add_preferred_console(ttyname, idx, devname, options, brl_options, true);
 	return 1;
-- 
2.53.0

On Thu, Sep 24, 2026 at 10:00:57AM +0300, David Engraf wrote:
> This fixes a regression when a console option includes ':'. Commit
> 7640f1a44eba ("printk: Add match_devname_and_update_preferred_console()")
> introduced console=DEVNAME:0.0 hardware style addressing by looking for a
> colon. If the colon is part of an option the name is handled as devname
> instead of ttyname.
> 
> Fix by handling the options first which will add a NULL terminator to the
> string and refactor idx handling to clean up the code (thanks to Petr
> Mladek).

Maybe clarify the above a bit to make it clear that the refactoring is
needed for the fix. Something like:

Fix by handling the options first which will add a NULL terminator to the 
string. Note that parsing the options first means that also idx parsing
needs changing. Handle the idx parsing by refactoring the code (thanks to
Petr Mladek).

Other than that:

Reviewed-by: Tony Lindgren <tony.lindgren@linux.intel.com>