[PATCH 5.10 428/599] kgdbts: fix return value of __setup handler

From: Greg Kroah-Hartman
Date: Tue Apr 05 2022 - 16:48:21 EST

From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

[ Upstream commit 96c9e802c64014a7716865332d732cc9c7f24593 ]

__setup() handlers should return 1 to indicate that the boot option
has been handled. A return of 0 causes the boot option/value to be
listed as an Unknown kernel parameter and added to init's (limited)
environment strings. So return 1 from kgdbts_option_setup().

Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc7
kgdboc=kbd kgdbts=", will be passed to user space.

Run /sbin/init as init process
with arguments:
with environment:

Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@xxxxxxxxxxxx
Fixes: e8d31c204e36 ("kgdb: add kgdb internal test suite")
Cc: kgdb-bugreport@xxxxxxxxxxxxxxxxxxxxx
Cc: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Cc: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Reported-by: Igor Zhbanov <i.zhbanov@xxxxxxxxxxxx>
Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220308033255.22118-1-rdunlap@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/misc/kgdbts.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c
index 49489153cd16..3e4d89471938 100644
--- a/drivers/misc/kgdbts.c
+++ b/drivers/misc/kgdbts.c
@@ -1060,10 +1060,10 @@ static int kgdbts_option_setup(char *opt)
if (strlen(opt) >= MAX_CONFIG_LEN) {
printk(KERN_ERR "kgdbts: config string too long\n");
- return -ENOSPC;
+ return 1;
strcpy(config, opt);
- return 0;
+ return 1;

__setup("kgdbts=", kgdbts_option_setup);