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Sun, 08 Nov 2026 04:50:54 -0800 (PST) Received: from fedora.jkuat.ac.ke ([41.204.187.5]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-495e725c4ccsm2177680f8f.53.2026.11.08.04.50.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 08 Nov 2026 04:50:54 -0800 (PST) From: Bramwel Barack To: gregkh@linuxfoundation.org, jirislaby@kernel.org Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Bramwel Barack Subject: [PATCH] tty: n_null: remove legacy BUG_ON() from module initialization Date: Sun, 8 Nov 2026 15:50:31 +0300 Message-ID: <20261108125031.33753-1-bramwelbarack89@gmail.com> X-Mailer: git-send-email 2.56.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The use of BUG_ON() in module initialization paths is heavily deprecated as it triggers a kernel panic and crashes the entire system for non-fatal registration failures. If tty_register_ldisc() fails (e.g., if the slot is already occupied), it should be handled gracefully. Modernize the initialization path by capturing the return value of tty_register_ldisc(), logging a clean error message via pr_err(), and propagating the error code back up to the module loader. Signed-off-by: Bramwel Barack --- drivers/tty/n_null.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/tty/n_null.c b/drivers/tty/n_null.c index 5a429d923eb3..886f6789f872 100644 --- a/drivers/tty/n_null.c +++ b/drivers/tty/n_null.c @@ -32,7 +32,14 @@ static struct tty_ldisc_ops null_ldisc = { static int __init n_null_init(void) { - BUG_ON(tty_register_ldisc(&null_ldisc)); + int ret; + + ret = tty_register_ldisc(&null_ldisc); + if (ret) { + pr_err("n_null: failed to register line discipline (%d)\n", ret); + return ret; + } + return 0; } -- 2.56.0