From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> [ Upstream commit ab818c7aa7544bf8d2dd4bdf68878b17a02eb332 ] __setup() handlers should return 1 to obsolete_checksetup() in init/main.c 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 kgdboc_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: /sbin/init with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc7 kgdboc=kbd kgdbts= Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@xxxxxxxxxxxx Fixes: 1bd54d851f50 ("kgdboc: Passing ekgdboc to command line causes panic") Fixes: f2d937f3bf00 ("consoles: polling support, kgdboc") Cc: He Zhe <zhe.he@xxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Jiri Slaby <jirislaby@xxxxxxxxxx> Cc: kgdb-bugreport@xxxxxxxxxxxxxxxxxxxxx Cc: Jason Wessel <jason.wessel@xxxxxxxxxxxxx> Cc: Daniel Thompson <daniel.thompson@xxxxxxxxxx> Cc: Douglas Anderson <dianders@xxxxxxxxxxxx> Cc: linux-serial@xxxxxxxxxxxxxxx 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/20220309033018.17936-1-rdunlap@xxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/tty/serial/kgdboc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c index 49d0c7f2b29b..79b7db8580e0 100644 --- a/drivers/tty/serial/kgdboc.c +++ b/drivers/tty/serial/kgdboc.c @@ -403,16 +403,16 @@ static int kgdboc_option_setup(char *opt) { if (!opt) { pr_err("config string not provided\n"); - return -EINVAL; + return 1; } if (strlen(opt) >= MAX_CONFIG_LEN) { pr_err("config string too long\n"); - return -ENOSPC; + return 1; } strcpy(config, opt); - return 0; + return 1; } __setup("kgdboc=", kgdboc_option_setup); -- 2.34.1