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Fri, 06 Feb 2026 05:40:54 -0800 (PST) Received: from localhost ([196.207.164.177]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-436296b25casm6293951f8f.4.2026.02.06.05.40.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Feb 2026 05:40:54 -0800 (PST) Date: Fri, 6 Feb 2026 16:40:51 +0300 From: Dan Carpenter To: Alain Volmat Cc: linux-spi@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel Subject: [bug report] spi: stm32: properly fail on dma_request_chan error Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: [ Smatch checking is paused while we raise funding. #SadFace https://lore.kernel.org/all/aTaiGSbWZ9DJaGo7@stanley.mountain/ -dan ] Hello Alain Volmat, Commit c266d19b7d4e ("spi: stm32: properly fail on dma_request_chan error") from Dec 18, 2025 (linux-next), leads to the following Smatch static checker warning: drivers/spi/spi-stm32.c:2578 stm32_spi_probe() error: 'spi->dma_rx' dereferencing possible ERR_PTR() drivers/spi/spi-stm32.c 2480 if (STM32_SPI_DEVICE_MODE(spi)) 2481 ctrl->target_abort = stm32h7_spi_device_abort; 2482 2483 spi->dma_tx = dma_request_chan(spi->dev, "tx"); 2484 if (IS_ERR(spi->dma_tx)) { 2485 ret = PTR_ERR(spi->dma_tx); 2486 if (ret == -ENODEV) { 2487 dev_info(&pdev->dev, "tx dma disabled\n"); 2488 spi->dma_tx = NULL; 2489 } else { 2490 dev_err_probe(&pdev->dev, ret, "failed to request tx dma channel\n"); 2491 goto err_clk_disable; 2492 } 2493 } else { 2494 ctrl->dma_tx = spi->dma_tx; 2495 } 2496 2497 spi->dma_rx = dma_request_chan(spi->dev, "rx"); 2498 if (IS_ERR(spi->dma_rx)) { 2499 ret = PTR_ERR(spi->dma_rx); 2500 if (ret == -ENODEV) { 2501 dev_info(&pdev->dev, "rx dma disabled\n"); 2502 spi->dma_rx = NULL; 2503 } else { 2504 dev_err_probe(&pdev->dev, ret, "failed to request rx dma channel\n"); 2505 goto err_dma_release; spi->dma_rx is an erorr pointer at this goto so it will crash. 2506 } 2507 } else { 2508 ctrl->dma_rx = spi->dma_rx; 2509 } 2510 2511 if (spi->dma_tx || spi->dma_rx) 2512 ctrl->can_dma = stm32_spi_can_dma; 2513 2514 spi->sram_pool = of_gen_pool_get(pdev->dev.of_node, "sram", 0); 2515 if (spi->sram_pool) { 2516 spi->sram_rx_buf_size = gen_pool_size(spi->sram_pool); 2517 dev_info(&pdev->dev, "SRAM pool: %zu KiB for RX DMA/MDMA chaining\n", 2518 spi->sram_rx_buf_size / 1024); 2519 spi->sram_rx_buf = gen_pool_dma_zalloc(spi->sram_pool, spi->sram_rx_buf_size, 2520 &spi->sram_dma_rx_buf); 2521 if (!spi->sram_rx_buf) { 2522 dev_err(&pdev->dev, "failed to allocate SRAM buffer\n"); 2523 } else { 2524 spi->mdma_rx = dma_request_chan(spi->dev, "rxm2m"); 2525 if (IS_ERR(spi->mdma_rx)) { 2526 ret = PTR_ERR(spi->mdma_rx); 2527 spi->mdma_rx = NULL; 2528 if (ret == -EPROBE_DEFER) { 2529 goto err_pool_free; 2530 } else { 2531 gen_pool_free(spi->sram_pool, 2532 (unsigned long)spi->sram_rx_buf, 2533 spi->sram_rx_buf_size); 2534 dev_warn(&pdev->dev, 2535 "failed to request rx mdma channel, DMA only\n"); 2536 } 2537 } 2538 } 2539 } 2540 2541 pm_runtime_set_autosuspend_delay(&pdev->dev, 2542 STM32_SPI_AUTOSUSPEND_DELAY); 2543 pm_runtime_use_autosuspend(&pdev->dev); 2544 pm_runtime_set_active(&pdev->dev); 2545 pm_runtime_get_noresume(&pdev->dev); 2546 pm_runtime_enable(&pdev->dev); 2547 2548 ret = spi_register_controller(ctrl); 2549 if (ret) { 2550 dev_err(&pdev->dev, "spi controller registration failed: %d\n", 2551 ret); 2552 goto err_pm_disable; 2553 } 2554 2555 pm_runtime_put_autosuspend(&pdev->dev); 2556 2557 dev_info(&pdev->dev, "driver initialized (%s mode)\n", 2558 STM32_SPI_HOST_MODE(spi) ? "host" : "device"); 2559 2560 return 0; 2561 2562 err_pm_disable: 2563 pm_runtime_disable(&pdev->dev); 2564 pm_runtime_put_noidle(&pdev->dev); 2565 pm_runtime_set_suspended(&pdev->dev); 2566 pm_runtime_dont_use_autosuspend(&pdev->dev); 2567 2568 if (spi->mdma_rx) 2569 dma_release_channel(spi->mdma_rx); 2570 err_pool_free: 2571 if (spi->sram_pool) 2572 gen_pool_free(spi->sram_pool, (unsigned long)spi->sram_rx_buf, 2573 spi->sram_rx_buf_size); 2574 err_dma_release: 2575 if (spi->dma_tx) 2576 dma_release_channel(spi->dma_tx); 2577 if (spi->dma_rx) --> 2578 dma_release_channel(spi->dma_rx); ^^^^^^^^^^^ Here. 2579 err_clk_disable: 2580 clk_disable_unprepare(spi->clk); 2581 2582 return ret; 2583 } regards, dan carpenter