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 6AD691F16B; Sat, 17 Oct 2026 17:32:24 +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=1792258345; cv=none; b=B+xMHSwuFPDnFmdY6CTiKVqJMRjMGztS1wn0yHtkzBJS67/3d4xv27E+lYlOZXcvl8T9Qf1SXt5BZLYVa7PVomEcukCeQrWVAgllcVrjwzfDaVNkvo9Zs5H7Jz8O0K/3FHtlyadtnbXOfXlmgGB6SF0OjyWSWMhzqeDW5UOodt0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258345; c=relaxed/simple; bh=gUQ4rhjBs5JrOd3fp1uMUs9qSLYV+c77W2y5zBbfp2g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eszT9tYEeRQZgHZbh5e2+J1mt1dBk/cwuSszXKezU1KsIlf9KIbjQDNriiiUOEmPujdaoJYjPHIv+TBbW1ew1xIjtOlXlIgPUYDG91SknDovGIfKi98T3GwcH/yN8LRhsQjSmw/1tI5R5xZXseJrH7MmLvmt9nQUS31PdFBxMu0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Y7meusQt; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Y7meusQt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C414A1F000C4; Sat, 17 Oct 2026 17:32:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792258344; bh=4+ZIzXFK1hTlXSrxtGMJS+kUJlESTbEpFMqX9B4wSU0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Y7meusQtGK8sSRuZlX3dcmuLX6dOtZWKdYBGBXOzeS/BHEssd+m2IT7LzkOgg67fY OkIpL+HcbVV/7acxYB7silQ02HEvK+V9+PMnyVNZ7FzqHE1QRGynGN4q0ozG6mRl5Y OgWC9fq07bMeJH7XnyQv1i8CplJWHww1DU2D47Hc= 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 6.6 0854/1674] spi: tegra210-quad: Protect curr_xfer check in IRQ handler Date: Sat, 17 Oct 2026 17:52:06 +0200 Message-ID: <20261017160453.043082186@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-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 f7677b960c342..8af5892ac738e 100644 --- a/drivers/spi/spi-tegra210-quad.c +++ b/drivers/spi/spi-tegra210-quad.c @@ -1351,6 +1351,11 @@ 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); @@ -1419,6 +1424,11 @@ 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 (err) { tegra_qspi_dma_unmap_xfer(tqspi, t); tegra_qspi_handle_error(tqspi); @@ -1457,6 +1467,7 @@ 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; /* @@ -1474,7 +1485,9 @@ 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; @@ -1491,7 +1504,14 @@ 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); -- 2.53.0