Hi Xianwei, kernel test robot noticed the following build warnings:
url: https://github.com/intel-lab-lkp/linux/commits/Xianwei-Zhao-via-B4-Relay/dt-bindings-dma-Add-Amlogic-A9-SoC-DMA/20260227-152743 base: 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f patch link: https://lore.kernel.org/r/20260227-amlogic-dma-v4-2-f25e4614e9b7%40amlogic.com patch subject: [PATCH v4 2/3] dma: amlogic: Add general DMA driver for A9 config: arm-randconfig-r073-20260228 (https://download.01.org/0day-ci/archive/20260302/[email protected]/config) compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18) smatch version: v0.5.0-8994-gd50c5a4c If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <[email protected]> | Reported-by: Dan Carpenter <[email protected]> | Closes: https://lore.kernel.org/r/[email protected]/ New smatch warnings: drivers/dma/amlogic-dma.c:354 aml_dma_interrupt_handler() warn: variable dereferenced before check 'aml_chan' (see line 353) drivers/dma/amlogic-dma.c:483 aml_dma_probe() warn: passing zero to 'PTR_ERR' Old smatch warnings: drivers/dma/amlogic-dma.c:384 aml_dma_interrupt_handler() warn: variable dereferenced before check 'aml_chan' (see line 383) vim +/aml_chan +354 drivers/dma/amlogic-dma.c c01d15789f1d15b Xianwei Zhao 2026-02-27 335 static irqreturn_t aml_dma_interrupt_handler(int irq, void *dev_id) c01d15789f1d15b Xianwei Zhao 2026-02-27 336 { c01d15789f1d15b Xianwei Zhao 2026-02-27 337 struct aml_dma_dev *aml_dma = dev_id; c01d15789f1d15b Xianwei Zhao 2026-02-27 338 struct aml_dma_chan *aml_chan; c01d15789f1d15b Xianwei Zhao 2026-02-27 339 u32 done, eoc_done, err, err_l, end; c01d15789f1d15b Xianwei Zhao 2026-02-27 340 int i = 0; c01d15789f1d15b Xianwei Zhao 2026-02-27 341 c01d15789f1d15b Xianwei Zhao 2026-02-27 342 /* deal with rch normal complete and error */ c01d15789f1d15b Xianwei Zhao 2026-02-27 343 regmap_read(aml_dma->regmap, RCH_DONE, &done); c01d15789f1d15b Xianwei Zhao 2026-02-27 344 regmap_read(aml_dma->regmap, RCH_ERR, &err); c01d15789f1d15b Xianwei Zhao 2026-02-27 345 regmap_read(aml_dma->regmap, RCH_LEN_ERR, &err_l); c01d15789f1d15b Xianwei Zhao 2026-02-27 346 err = err | err_l; c01d15789f1d15b Xianwei Zhao 2026-02-27 347 c01d15789f1d15b Xianwei Zhao 2026-02-27 348 done = done | err; c01d15789f1d15b Xianwei Zhao 2026-02-27 349 c01d15789f1d15b Xianwei Zhao 2026-02-27 350 while (done) { c01d15789f1d15b Xianwei Zhao 2026-02-27 351 i = ffs(done) - 1; c01d15789f1d15b Xianwei Zhao 2026-02-27 352 aml_chan = aml_dma->aml_rch[i]; c01d15789f1d15b Xianwei Zhao 2026-02-27 @353 regmap_write(aml_dma->regmap, CLEAR_RCH, BIT(aml_chan->chan_id)); ^^^^^^^^^^^^^^^^^^ Move this dereference c01d15789f1d15b Xianwei Zhao 2026-02-27 @354 if (!aml_chan) { ^^^^^^^^ after this NULL check? c01d15789f1d15b Xianwei Zhao 2026-02-27 355 dev_err(aml_dma->dma_device.dev, "idx %d rch not initialized\n", i); c01d15789f1d15b Xianwei Zhao 2026-02-27 356 done &= ~BIT(i); c01d15789f1d15b Xianwei Zhao 2026-02-27 357 continue; c01d15789f1d15b Xianwei Zhao 2026-02-27 358 } c01d15789f1d15b Xianwei Zhao 2026-02-27 359 aml_chan->status = (err & (1 << i)) ? DMA_ERROR : DMA_COMPLETE; c01d15789f1d15b Xianwei Zhao 2026-02-27 360 dma_cookie_complete(&aml_chan->desc); c01d15789f1d15b Xianwei Zhao 2026-02-27 361 dmaengine_desc_get_callback_invoke(&aml_chan->desc, NULL); c01d15789f1d15b Xianwei Zhao 2026-02-27 362 done &= ~BIT(i); c01d15789f1d15b Xianwei Zhao 2026-02-27 363 } c01d15789f1d15b Xianwei Zhao 2026-02-27 364 c01d15789f1d15b Xianwei Zhao 2026-02-27 365 /* deal with wch normal complete and error */ c01d15789f1d15b Xianwei Zhao 2026-02-27 366 regmap_read(aml_dma->regmap, DMA_BATCH_END, &end); c01d15789f1d15b Xianwei Zhao 2026-02-27 367 if (end) c01d15789f1d15b Xianwei Zhao 2026-02-27 368 regmap_write(aml_dma->regmap, CLEAR_W_BATCH, end); c01d15789f1d15b Xianwei Zhao 2026-02-27 369 c01d15789f1d15b Xianwei Zhao 2026-02-27 370 regmap_read(aml_dma->regmap, WCH_DONE, &done); c01d15789f1d15b Xianwei Zhao 2026-02-27 371 regmap_read(aml_dma->regmap, WCH_EOC_DONE, &eoc_done); c01d15789f1d15b Xianwei Zhao 2026-02-27 372 done = done | eoc_done; c01d15789f1d15b Xianwei Zhao 2026-02-27 373 c01d15789f1d15b Xianwei Zhao 2026-02-27 374 regmap_read(aml_dma->regmap, WCH_ERR, &err); c01d15789f1d15b Xianwei Zhao 2026-02-27 375 regmap_read(aml_dma->regmap, WDMA_RESP_ERR, &err_l); c01d15789f1d15b Xianwei Zhao 2026-02-27 376 err = err | err_l; c01d15789f1d15b Xianwei Zhao 2026-02-27 377 c01d15789f1d15b Xianwei Zhao 2026-02-27 378 done = done | err; c01d15789f1d15b Xianwei Zhao 2026-02-27 379 i = 0; c01d15789f1d15b Xianwei Zhao 2026-02-27 380 while (done) { c01d15789f1d15b Xianwei Zhao 2026-02-27 381 i = ffs(done) - 1; c01d15789f1d15b Xianwei Zhao 2026-02-27 382 aml_chan = aml_dma->aml_wch[i]; c01d15789f1d15b Xianwei Zhao 2026-02-27 383 regmap_write(aml_dma->regmap, CLEAR_WCH, BIT(aml_chan->chan_id)); c01d15789f1d15b Xianwei Zhao 2026-02-27 384 if (!aml_chan) { Same. c01d15789f1d15b Xianwei Zhao 2026-02-27 385 dev_err(aml_dma->dma_device.dev, "idx %d wch not initialized\n", i); c01d15789f1d15b Xianwei Zhao 2026-02-27 386 done &= ~BIT(i); c01d15789f1d15b Xianwei Zhao 2026-02-27 387 continue; c01d15789f1d15b Xianwei Zhao 2026-02-27 388 } c01d15789f1d15b Xianwei Zhao 2026-02-27 389 aml_chan->status = (err & (1 << i)) ? DMA_ERROR : DMA_COMPLETE; c01d15789f1d15b Xianwei Zhao 2026-02-27 390 dma_cookie_complete(&aml_chan->desc); c01d15789f1d15b Xianwei Zhao 2026-02-27 391 dmaengine_desc_get_callback_invoke(&aml_chan->desc, NULL); c01d15789f1d15b Xianwei Zhao 2026-02-27 392 done &= ~BIT(i); c01d15789f1d15b Xianwei Zhao 2026-02-27 393 } c01d15789f1d15b Xianwei Zhao 2026-02-27 394 c01d15789f1d15b Xianwei Zhao 2026-02-27 395 return IRQ_HANDLED; c01d15789f1d15b Xianwei Zhao 2026-02-27 396 } [ snip ] c01d15789f1d15b Xianwei Zhao 2026-02-27 450 static int aml_dma_probe(struct platform_device *pdev) c01d15789f1d15b Xianwei Zhao 2026-02-27 451 { c01d15789f1d15b Xianwei Zhao 2026-02-27 452 struct device_node *np = pdev->dev.of_node; c01d15789f1d15b Xianwei Zhao 2026-02-27 453 struct dma_device *dma_dev; c01d15789f1d15b Xianwei Zhao 2026-02-27 454 struct aml_dma_dev *aml_dma; c01d15789f1d15b Xianwei Zhao 2026-02-27 455 int ret, i, len; c01d15789f1d15b Xianwei Zhao 2026-02-27 456 u32 chan_nr; c01d15789f1d15b Xianwei Zhao 2026-02-27 457 c01d15789f1d15b Xianwei Zhao 2026-02-27 458 const struct regmap_config aml_regmap_config = { c01d15789f1d15b Xianwei Zhao 2026-02-27 459 .reg_bits = 32, c01d15789f1d15b Xianwei Zhao 2026-02-27 460 .val_bits = 32, c01d15789f1d15b Xianwei Zhao 2026-02-27 461 .reg_stride = 4, c01d15789f1d15b Xianwei Zhao 2026-02-27 462 .max_register = 0x3000, c01d15789f1d15b Xianwei Zhao 2026-02-27 463 }; c01d15789f1d15b Xianwei Zhao 2026-02-27 464 c01d15789f1d15b Xianwei Zhao 2026-02-27 465 ret = of_property_read_u32(np, "dma-channels", &chan_nr); c01d15789f1d15b Xianwei Zhao 2026-02-27 466 if (ret) c01d15789f1d15b Xianwei Zhao 2026-02-27 467 return dev_err_probe(&pdev->dev, ret, "failed to read dma-channels\n"); c01d15789f1d15b Xianwei Zhao 2026-02-27 468 c01d15789f1d15b Xianwei Zhao 2026-02-27 469 len = sizeof(struct aml_dma_dev) + sizeof(struct aml_dma_chan) * chan_nr; c01d15789f1d15b Xianwei Zhao 2026-02-27 470 aml_dma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL); c01d15789f1d15b Xianwei Zhao 2026-02-27 471 if (!aml_dma) c01d15789f1d15b Xianwei Zhao 2026-02-27 472 return -ENOMEM; c01d15789f1d15b Xianwei Zhao 2026-02-27 473 c01d15789f1d15b Xianwei Zhao 2026-02-27 474 aml_dma->chan_nr = chan_nr; c01d15789f1d15b Xianwei Zhao 2026-02-27 475 c01d15789f1d15b Xianwei Zhao 2026-02-27 476 aml_dma->base = devm_platform_ioremap_resource(pdev, 0); c01d15789f1d15b Xianwei Zhao 2026-02-27 477 if (IS_ERR(aml_dma->base)) c01d15789f1d15b Xianwei Zhao 2026-02-27 478 return PTR_ERR(aml_dma->base); c01d15789f1d15b Xianwei Zhao 2026-02-27 479 c01d15789f1d15b Xianwei Zhao 2026-02-27 480 aml_dma->regmap = devm_regmap_init_mmio(&pdev->dev, aml_dma->base, c01d15789f1d15b Xianwei Zhao 2026-02-27 481 &aml_regmap_config); c01d15789f1d15b Xianwei Zhao 2026-02-27 482 if (IS_ERR_OR_NULL(aml_dma->regmap)) This should just be if (IS_ERR(aml_dma->regmap)) since devm_regmap_init_mmio() can't return NULL. https://staticthinking.wordpress.com/2022/08/01/mixing-error-pointers-and-null/ c01d15789f1d15b Xianwei Zhao 2026-02-27 @483 return PTR_ERR(aml_dma->regmap); c01d15789f1d15b Xianwei Zhao 2026-02-27 484 c01d15789f1d15b Xianwei Zhao 2026-02-27 485 aml_dma->clk = devm_clk_get_enabled(&pdev->dev, NULL); c01d15789f1d15b Xianwei Zhao 2026-02-27 486 if (IS_ERR(aml_dma->clk)) c01d15789f1d15b Xianwei Zhao 2026-02-27 487 return PTR_ERR(aml_dma->clk); c01d15789f1d15b Xianwei Zhao 2026-02-27 488 c01d15789f1d15b Xianwei Zhao 2026-02-27 489 aml_dma->irq = platform_get_irq(pdev, 0); c01d15789f1d15b Xianwei Zhao 2026-02-27 490 c01d15789f1d15b Xianwei Zhao 2026-02-27 491 aml_dma->pdev = pdev; c01d15789f1d15b Xianwei Zhao 2026-02-27 492 aml_dma->dma_device.dev = &pdev->dev; c01d15789f1d15b Xianwei Zhao 2026-02-27 493 c01d15789f1d15b Xianwei Zhao 2026-02-27 494 dma_dev = &aml_dma->dma_device; c01d15789f1d15b Xianwei Zhao 2026-02-27 495 INIT_LIST_HEAD(&dma_dev->channels); -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
