From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7F129345EBF for ; Fri, 4 Sep 2026 13:18:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788527929; cv=none; b=tZYo3AzqdMO8F5vmXwRYW3LkbMT0JXhqfTgLRFznghc7XQqHjFZx9mMCEAHvpUHbPW316L/THe0777XpFxwrkslGDCTxUZjgS5K2ICfWRGhPTBpV+3z487NWqlUPtMrM26CXbKS2oI94uoT54l0Sz+ceRvjOLB6G70y5+5xWTZ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788527929; c=relaxed/simple; bh=BM9A8qHGvdn+KOWbJ2kS8pvO6sijMHCanOKVCkSDKnE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IJI4QewxeshprGRO+3U78OYYssGSziezYNN8ak/gRIQOPTRt46+1B+LTvjXfo7qecb4mVNPsjRV09l6OnJH0d9vQ5A3Fl6CFk2J749AW9c1z6KBfmQBbUSLq7Ee1439+YiNK1UVl/kcOPE1CS2MkEdwXLsnvz7w7tSsCKUgkhKQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iV2nCFNX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iV2nCFNX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F8361F00A3D; Fri, 4 Sep 2026 13:18:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788527923; bh=EEQvjX8deuPsU/QGCCHM0gR3Y961v6ydgjBm+GcDUoo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=iV2nCFNX3LMCoj1iYSk4OCPFieYE+1RYcNs0xYXJtKt7Y2fMLMiI4lUi5hYQYhVI4 3LejHFJ56aujZ6npceQ0qSfMjAxJbq1Wi2kmezHv7stNAinrFNbOm1hJ0JjNjNoWbw Dl947O4nfM71q9M/5i8IesvBlr/sUgtMHwT2S1q9/45HP+zhP1CG0k71WaLDWolhUP Kwr98O7iPLTuuMNEFvlEQ8cLEGSfczJVZGmO2M9gxltBhSOkPGaQ00z7q8hee+hzJn Gl66T+RNyLFIR8dne+emKlLuivFQNykhcdjfU5dufpwcki9N2XQATCYcpOBYFjr2t/ yiKhDqwpRN7KQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Karl Mehltretter , Sashiko , Frank Li , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 5.15.y 2/2] serial: imx: serialize imx_uart_ports[] lifetime Date: Fri, 4 Sep 2026 09:18:40 -0400 Message-ID: <20260904131840.506263-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260904131840.506263-1-sashal@kernel.org> References: <2026090333-scared-direness-4881@gregkh> <20260904131840.506263-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Karl Mehltretter [ Upstream commit 8b0b29fdcb47907ae0296b8fe829e918e05e300f ] imx_uart_probe() publishes its devm-allocated port in imx_uart_ports[] before uart_add_one_port() because console setup uses the table. The entry is not cleared when adding the port fails or after removal, leaving a dangling pointer. A sibling probe can register the shared console through that stale entry. This was reproduced under KASAN on QEMU mcimx6ul-evk by unbinding a sibling UART, unbinding the console UART and rebinding the sibling. Keep the entry valid through uart_remove_one_port(), then clear it. Protect port addition and removal together with their table updates so sibling operations cannot interleave. Reject an occupied slot rather than clobbering an active port during a duplicate-line probe. Fixes: dbff4e9ea2e8 ("IMX UART: remove statically initialized tables") Fixes: 9f322ad064f9 ("imx: serial: handle initialisation failure correctly") Reported-by: Sashiko Link: https://lore.kernel.org/all/20260719162850.043B41F000E9@smtp.kernel.org Link: https://lore.kernel.org/all/20260719222501.CB4CB1F000E9@smtp.kernel.org Cc: stable@vger.kernel.org Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260731181844.11330-6-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman [ replaced scoped_guard() with explicit mutex_lock()/mutex_unlock() calls for GNU89 compatibility ] Signed-off-by: Sasha Levin --- drivers/tty/serial/imx.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index ba64da1ca7b19..11338cb7b2112 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -2005,6 +2006,9 @@ static const struct uart_ops imx_uart_pops = { static struct imx_port *imx_uart_ports[UART_NR]; +/* Held across uart_add/remove_one_port(); console callbacks must not take it. */ +static DEFINE_MUTEX(imx_uart_ports_lock); + #if IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE) static void imx_uart_console_putchar(struct uart_port *port, int ch) { @@ -2472,11 +2476,18 @@ static int imx_uart_probe(struct platform_device *pdev) } } - imx_uart_ports[sport->port.line] = sport; - platform_set_drvdata(pdev, sport); - ret = uart_add_one_port(&imx_uart_uart_driver, &sport->port); + mutex_lock(&imx_uart_ports_lock); + if (imx_uart_ports[sport->port.line]) { + ret = -EBUSY; + } else { + imx_uart_ports[sport->port.line] = sport; + ret = uart_add_one_port(&imx_uart_uart_driver, &sport->port); + if (ret) + imx_uart_ports[sport->port.line] = NULL; + } + mutex_unlock(&imx_uart_ports_lock); err_clk: clk_disable_unprepare(sport->clk_ipg); @@ -2488,7 +2499,9 @@ static void imx_uart_remove(struct platform_device *pdev) { struct imx_port *sport = platform_get_drvdata(pdev); + guard(mutex)(&imx_uart_ports_lock); uart_remove_one_port(&imx_uart_uart_driver, &sport->port); + imx_uart_ports[sport->port.line] = NULL; } static void imx_uart_restore_context(struct imx_port *sport) -- 2.53.0