From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CA68D143888; Tue, 23 Apr 2024 21:43:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713908631; cv=none; b=kbPhAd0PKzlMEMwBHvHty2vQbMeZyfy68kfZKS73zlrSroYBrlNr/14Vk18rH+URjsaCf5i3C/OhBpIN35akAHHwqezDGVGUsMrfU5c8CmhI/dFmR6gZOu5sE0owqPQFXiqYRl+G+EnprdMvoQwJsjruu0XKsqBC7kH8hDKQ7Ak= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713908631; c=relaxed/simple; bh=MfoT0RlPWWbruz5KfyNMTjg0AtOLDXCTaWcdlBywGv8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ErQbOUxm8vIHuFZpUo+FGDK+AaJwEOoM2/SEM4RTgaU5gOQZDEMpqrTVGdO5rXAi/Q46eetocZSs1U/b3uNVFVgSA7r4U5dFiaCWiAyNWr/VIBJXowXo6aNRxKHno9+Q+5LqP0Wmru+MDa3wqtcSzE762AJxkZsHj2j7iH4Xk8c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZVRquKLe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ZVRquKLe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A02E6C3277B; Tue, 23 Apr 2024 21:43:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1713908631; bh=MfoT0RlPWWbruz5KfyNMTjg0AtOLDXCTaWcdlBywGv8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZVRquKLewkyViWvvfEb0/Cb57vVt0nLZY0k+aE/oaP4YFg1eYmCAVQyzihcyPU1sb p9uTIq+G3/+GsP7nCjqs34NhTtnIvPcw5o25eB6bKNbj6LISAbdMaA35vlNesVj+Z+ QaFme/kqOIk9WkaUt02g/MFrxRE6HpmnoutQHKLA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Subject: [PATCH 6.6 111/158] serial: stm32: Return IRQ_NONE in the ISR if no handling happend Date: Tue, 23 Apr 2024 14:39:08 -0700 Message-ID: <20240423213859.352676091@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240423213855.696477232@linuxfoundation.org> References: <20240423213855.696477232@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Uwe Kleine-König commit 13c785323b36b845300b256d0e5963c3727667d7 upstream. If there is a stuck irq that the handler doesn't address, returning IRQ_HANDLED unconditionally makes it impossible for the irq core to detect the problem and disable the irq. So only return IRQ_HANDLED if an event was handled. A stuck irq is still problematic, but with this change at least it only makes the UART nonfunctional instead of occupying the (usually only) CPU by 100% and so stall the whole machine. Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver") Cc: stable@vger.kernel.org Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/5f92603d0dfd8a5b8014b2b10a902d91e0bb881f.1713344161.git.u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -857,6 +857,7 @@ static irqreturn_t stm32_usart_interrupt const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; u32 sr; unsigned int size; + irqreturn_t ret = IRQ_NONE; sr = readl_relaxed(port->membase + ofs->isr); @@ -865,11 +866,14 @@ static irqreturn_t stm32_usart_interrupt (sr & USART_SR_TC)) { stm32_usart_tc_interrupt_disable(port); stm32_usart_rs485_rts_disable(port); + ret = IRQ_HANDLED; } - if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) + if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) { writel_relaxed(USART_ICR_RTOCF, port->membase + ofs->icr); + ret = IRQ_HANDLED; + } if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) { /* Clear wake up flag and disable wake up interrupt */ @@ -878,6 +882,7 @@ static irqreturn_t stm32_usart_interrupt stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE); if (irqd_is_wakeup_set(irq_get_irq_data(port->irq))) pm_wakeup_event(tport->tty->dev, 0); + ret = IRQ_HANDLED; } /* @@ -892,6 +897,7 @@ static irqreturn_t stm32_usart_interrupt uart_unlock_and_check_sysrq(port); if (size) tty_flip_buffer_push(tport); + ret = IRQ_HANDLED; } } @@ -899,6 +905,7 @@ static irqreturn_t stm32_usart_interrupt spin_lock(&port->lock); stm32_usart_transmit_chars(port); spin_unlock(&port->lock); + ret = IRQ_HANDLED; } /* Receiver timeout irq for DMA RX */ @@ -908,9 +915,10 @@ static irqreturn_t stm32_usart_interrupt uart_unlock_and_check_sysrq(port); if (size) tty_flip_buffer_push(tport); + ret = IRQ_HANDLED; } - return IRQ_HANDLED; + return ret; } static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)