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 38CE31AF0AF; Mon, 9 Feb 2026 14:34:32 +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=1770647672; cv=none; b=RlEAEPSMLn4zN89gardanKpjzsJEKMLocqJZCO5VJlHTb6EGPouGnx6RoTKXk1izhtCLVtt3TJ4o5qh9YYsNG6kBZRYGkPXGKhHQZHK/U0OW4LzCakENrnUWO1MSkGKobc/MQ9pGYAQn1N6Tnh0IllWdHY9cv7nlo39YL0qDPfA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770647672; c=relaxed/simple; bh=to7FSvaBX4amYQGL81IFT+YzNQ+oZL4Cv11e5Y1Zkxg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WG0t/AmXC9xCwaOO9lAL/kUjiQk/okyK9K2fZzyg+U53Z0jxhKn3SSnEIBkXSijKx/QjFRBAFlNFAU/B4KkGNNvZfKdecz2i9YPUVTN8fs5+wuz167gGeDgOjLWRiNb3mly1q/Bc/Ep8ch3iMH7TwiXQNUUEgLMF9WIQJNTFpxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=z+4ma1kd; 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="z+4ma1kd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4617C116C6; Mon, 9 Feb 2026 14:34:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1770647672; bh=to7FSvaBX4amYQGL81IFT+YzNQ+oZL4Cv11e5Y1Zkxg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=z+4ma1kd8kMoG83Mk26yPNiFmenYPdCDGIa7cJiNWUWMWpEOAISzEI8ddfbtIMFBt 4BDGZl1KhyfE4+8oN4jmPLQiimigMC/Exg1l/suzORdKetMXKaHQc0G4+gJgWQ3HZ8 ms1tIxzjqlPHd9d21QKUnhGC6s3BL+PbhLbE43Sg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Breno Leitao , Jon Hunter , Thierry Reding , Mark Brown , Sasha Levin Subject: [PATCH 6.18 170/175] spi: tegra210-quad: Protect curr_xfer check in IRQ handler Date: Mon, 9 Feb 2026 15:24:03 +0100 Message-ID: <20260209142326.597230493@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260209142320.474120190@linuxfoundation.org> References: <20260209142320.474120190@linuxfoundation.org> User-Agent: quilt/0.69 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-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Breno Leitao [ Upstream commit edf9088b6e1d6d88982db7eb5e736a0e4fbcc09e ] Now that all other accesses to curr_xfer are done under the lock, protect the curr_xfer NULL check in tegra_qspi_isr_thread() with the spinlock. Without this protection, the following race can occur: CPU0 (ISR thread) CPU1 (timeout path) ---------------- ------------------- if (!tqspi->curr_xfer) // sees non-NULL spin_lock() tqspi->curr_xfer = NULL spin_unlock() handle_*_xfer() spin_lock() t = tqspi->curr_xfer // NULL! ... t->len ... // NULL dereference! With this patch, all curr_xfer accesses are now properly synchronized. Although all accesses to curr_xfer are done under the lock, in tegra_qspi_isr_thread() it checks for NULL, releases the lock and reacquires it later in handle_cpu_based_xfer()/handle_dma_based_xfer(). There is a potential for an update in between, which could cause a NULL pointer dereference. To handle this, add a NULL check inside the handlers after acquiring the lock. This ensures that if the timeout path has already cleared curr_xfer, the handler will safely return without dereferencing the NULL pointer. Fixes: b4e002d8a7ce ("spi: tegra210-quad: Fix timeout handling") Signed-off-by: Breno Leitao Tested-by: Jon Hunter Acked-by: Jon Hunter Acked-by: Thierry Reding Link: https://patch.msgid.link/20260126-tegra_xfer-v2-6-6d2115e4f387@debian.org Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-tegra210-quad.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/spi/spi-tegra210-quad.c b/drivers/spi/spi-tegra210-quad.c index 7fe16ed7e84bd..83def82fe48c1 100644 --- a/drivers/spi/spi-tegra210-quad.c +++ b/drivers/spi/spi-tegra210-quad.c @@ -1393,6 +1393,11 @@ static irqreturn_t handle_cpu_based_xfer(struct tegra_qspi *tqspi) spin_lock_irqsave(&tqspi->lock, flags); t = tqspi->curr_xfer; + if (!t) { + spin_unlock_irqrestore(&tqspi->lock, flags); + return IRQ_HANDLED; + } + if (tqspi->tx_status || tqspi->rx_status) { tegra_qspi_handle_error(tqspi); complete(&tqspi->xfer_completion); @@ -1463,6 +1468,11 @@ static irqreturn_t handle_dma_based_xfer(struct tegra_qspi *tqspi) spin_lock_irqsave(&tqspi->lock, flags); t = tqspi->curr_xfer; + if (!t) { + spin_unlock_irqrestore(&tqspi->lock, flags); + return IRQ_HANDLED; + } + if (num_errors) { tegra_qspi_dma_unmap_xfer(tqspi, t); tegra_qspi_handle_error(tqspi); @@ -1501,6 +1511,7 @@ static irqreturn_t handle_dma_based_xfer(struct tegra_qspi *tqspi) static irqreturn_t tegra_qspi_isr_thread(int irq, void *context_data) { struct tegra_qspi *tqspi = context_data; + unsigned long flags; u32 status; /* @@ -1518,7 +1529,9 @@ static irqreturn_t tegra_qspi_isr_thread(int irq, void *context_data) * If no transfer is in progress, check if this was a real interrupt * that the timeout handler already processed, or a spurious one. */ + spin_lock_irqsave(&tqspi->lock, flags); if (!tqspi->curr_xfer) { + spin_unlock_irqrestore(&tqspi->lock, flags); /* Spurious interrupt - transfer not ready */ if (!(status & QSPI_RDY)) return IRQ_NONE; @@ -1535,7 +1548,14 @@ static irqreturn_t tegra_qspi_isr_thread(int irq, void *context_data) tqspi->rx_status = tqspi->status_reg & (QSPI_RX_FIFO_OVF | QSPI_RX_FIFO_UNF); tegra_qspi_mask_clear_irq(tqspi); + spin_unlock_irqrestore(&tqspi->lock, flags); + /* + * Lock is released here but handlers safely re-check curr_xfer under + * lock before dereferencing. + * DMA handler also needs to sleep in wait_for_completion_*(), which + * cannot be done while holding spinlock. + */ if (!tqspi->is_curr_dma_xfer) return handle_cpu_based_xfer(tqspi); -- 2.51.0