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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, He Zhe <zhe.he@windriver.com>,
        Jiri Slaby <jirislaby@kernel.org>,
        kgdb-bugreport@lists.sourceforge.net,
        Jason Wessel <jason.wessel@windriver.com>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Douglas Anderson <dianders@chromium.org>,
        linux-serial@vger.kernel.org,
        Igor Zhbanov <i.zhbanov@omprussia.ru>,
        Randy Dunlap <rdunlap@infradead.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0705/1017] kgdboc: fix return value of __setup handler
Date:   Tue,  5 Apr 2022 09:26:58 +0200
Message-Id: <20220405070415.197909605@linuxfoundation.org>
In-Reply-To: <20220405070354.155796697@linuxfoundation.org>
References: <20220405070354.155796697@linuxfoundation.org>
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From: Randy Dunlap <rdunlap@infradead.org>

[ 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@omprussia.ru
Fixes: 1bd54d851f50 ("kgdboc: Passing ekgdboc to command line causes panic")
Fixes: f2d937f3bf00 ("consoles: polling support, kgdboc")
Cc: He Zhe <zhe.he@windriver.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: kgdb-bugreport@lists.sourceforge.net
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: linux-serial@vger.kernel.org
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220309033018.17936-1-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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