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[61.228.16.100]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-38e9205d358sm29366a91.3.2026.07.20.09.22.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Jul 2026 09:22:25 -0700 (PDT) From: Shih-Yuan Lee To: Dmitry Torokhov Cc: Mark Brown , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Shih-Yuan Lee Subject: [PATCH v3 1/5] Input: applespi - use unified wait queue with timeouts for drain Date: Tue, 21 Jul 2026 00:22:15 +0800 Message-Id: <20260720162219.32324-2-fourdollars@debian.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260720162219.32324-1-fourdollars@debian.org> References: <20260720162219.32324-1-fourdollars@debian.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Consolidate wait queues by renaming drain_complete to wait_queue and use wait_event_lock_irq_timeout() with a 3-second timeout during read and write drains to prevent indefinite lockups during driver unbind or PM transitions if the hardware becomes unresponsive. If a timeout occurs while a read or write transfer is still active, issue a warning and fallback to waiting unconditionally until the transfer completion callback clears the active flag. This guarantees that applespi_drain_writes() and applespi_drain_reads() never return prematurely while transfers are in flight, preventing use-after-free (UAF) and DMA memory corruption when devres frees the driver context and DMA buffers during unbind. Signed-off-by: Shih-Yuan Lee --- drivers/input/keyboard/applespi.c | 48 ++++++++++++++++++++++++------- 1 file changed, 38 insertions(+), 10 deletions(-) diff --git a/drivers/input/keyboard/applespi.c b/drivers/input/keyboard/applespi.c index b5ff71cd5a70..c501bf7e517e 100644 --- a/drivers/input/keyboard/applespi.c +++ b/drivers/input/keyboard/applespi.c @@ -417,7 +417,7 @@ struct applespi_data { bool suspended; bool drain; - wait_queue_head_t drain_complete; + wait_queue_head_t wait_queue; bool read_active; bool write_active; @@ -677,7 +677,7 @@ static int applespi_setup_spi(struct applespi_data *applespi) return sts; spin_lock_init(&applespi->cmd_msg_lock); - init_waitqueue_head(&applespi->drain_complete); + init_waitqueue_head(&applespi->wait_queue); return 0; } @@ -725,7 +725,7 @@ static void applespi_msg_complete(struct applespi_data *applespi, applespi->write_active = false; if (applespi->drain && !applespi->write_active) - wake_up_all(&applespi->drain_complete); + wake_up_all(&applespi->wait_queue); if (is_write_msg) { applespi->cmd_msg_queued = 0; @@ -1415,7 +1415,7 @@ static void applespi_got_data(struct applespi_data *applespi) applespi->read_active = false; applespi->write_active = false; - wake_up_all(&applespi->drain_complete); + wake_up_all(&applespi->wait_queue); } return; @@ -1793,21 +1793,49 @@ static int applespi_probe(struct spi_device *spi) static void applespi_drain_writes(struct applespi_data *applespi) { - guard(spinlock_irqsave)(&applespi->cmd_msg_lock); + unsigned long flags; + long ret; + + spin_lock_irqsave(&applespi->cmd_msg_lock, flags); applespi->drain = true; - wait_event_lock_irq(applespi->drain_complete, !applespi->write_active, - applespi->cmd_msg_lock); + ret = wait_event_lock_irq_timeout(applespi->wait_queue, + !applespi->write_active, + applespi->cmd_msg_lock, + msecs_to_jiffies(3000)); + if (!ret && applespi->write_active) { + dev_warn(&applespi->spi->dev, + "Timed out waiting for write drain, waiting unconditionally\n"); + wait_event_lock_irq(applespi->wait_queue, + !applespi->write_active, + applespi->cmd_msg_lock); + } + + spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags); } static void applespi_drain_reads(struct applespi_data *applespi) { - guard(spinlock_irqsave)(&applespi->cmd_msg_lock); + unsigned long flags; + long ret; - wait_event_lock_irq(applespi->drain_complete, !applespi->read_active, - applespi->cmd_msg_lock); + spin_lock_irqsave(&applespi->cmd_msg_lock, flags); + + ret = wait_event_lock_irq_timeout(applespi->wait_queue, + !applespi->read_active, + applespi->cmd_msg_lock, + msecs_to_jiffies(3000)); + if (!ret && applespi->read_active) { + dev_warn(&applespi->spi->dev, + "Timed out waiting for read drain, waiting unconditionally\n"); + wait_event_lock_irq(applespi->wait_queue, + !applespi->read_active, + applespi->cmd_msg_lock); + } applespi->suspended = true; + + spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags); } static void applespi_remove(struct spi_device *spi) -- 2.39.5