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 9A17A143898; Tue, 23 Apr 2024 21:41:57 +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=1713908517; cv=none; b=L+haQeihc5cfHXPQqhggNCC2BmVolLEJuIIpezce5iCqBh2X8mUIK6Pa99C2aKgyEdxDwb1OXGd10c+GejIDx0VwGBvJDJLq9pMGNWwIQxo7Y3jq7cxWvst5xm1C6S+5jS4T7pAbjVJUAsZK+hczaky+cCs/9SD+TD6nMpO9OJE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713908517; c=relaxed/simple; bh=K2tTR2ZzIRFEFg7q4VyrbR3zD3RxT/8ijj384SmsbvM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=myS9/qwGJn9C1/UeKlZN/6OCcM3kuguxEKj6sl/8IIGfufp8S7nhqyP8yxWtp8hGT9fehFADwrNSgtMT6ikyhfjw9Lf88CzHoA7+du6iBp4gQD4oz/rOz4BbcuhvT1CnCaaM8cyxYfe3aIj6xPOHu45Jqt1BnuhRGTR/HFuVwws= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2NrA4+LB; 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="2NrA4+LB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FB2EC3277B; Tue, 23 Apr 2024 21:41:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1713908517; bh=K2tTR2ZzIRFEFg7q4VyrbR3zD3RxT/8ijj384SmsbvM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2NrA4+LBrNeHXDk7DBtHF85ma03w52mVh4lPeqMXQ8B1DN2lnV51bTTfFHh3+ar/O SZ6zDkmTwAH/U0iCWlT2Kg8Lg9IR9W/g77c8NuACk//AbUHybexbUObTok0Xzsnsr4 muxlaKeLFwwlG7kGY3GEKtW6eoR+kT4fTI5EEZpc= 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 6.8 104/158] serial: stm32: Return IRQ_NONE in the ISR if no handling happend Date: Tue, 23 Apr 2024 14:38:46 -0700 Message-ID: <20240423213859.323299900@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240423213855.824778126@linuxfoundation.org> References: <20240423213855.824778126@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 6.8-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 uart_port_lock(port); stm32_usart_transmit_chars(port); uart_port_unlock(port); + 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)