Hello Cezary Rojewski,

The patch 3e9582267e3a: "ALSA: hda: Interrupt servicing and BDL setup for compress streams" from Dec 2, 2022, leads to the following Smatch static checker warning:

sound/hda/hdac_stream.c:544 snd_hdac_stream_setup_periods() error: uninitialized symbol 'dmab'.

sound/hda/hdac_stream.c 487 int snd_hdac_stream_setup_periods(struct hdac_stream *azx_dev) 488 { 489 struct hdac_bus *bus = azx_dev->bus; 490 struct snd_pcm_substream *substream = azx_dev->substream; 491 struct snd_compr_stream *cstream = azx_dev->cstream; 492 struct snd_pcm_runtime *runtime = NULL; 493 struct snd_dma_buffer *dmab; 494 __le32 *bdl; 495 int i, ofs, periods, period_bytes; 496 int pos_adj, pos_align; 497 498 if (substream) { 499 runtime = substream->runtime; 500 dmab = snd_pcm_get_dma_buf(substream); 501 } else if (cstream) { 502 dmab = snd_pcm_get_dma_buf(cstream); 503 }

dmab is not initialized on else path.

504 505 /* reset BDL address */ 506 snd_hdac_stream_writel(azx_dev, SD_BDLPL, 0); 507 snd_hdac_stream_writel(azx_dev, SD_BDLPU, 0); 508 509 period_bytes = azx_dev->period_bytes; 510 periods = azx_dev->bufsize / period_bytes; 511 512 /* program the initial BDL entries */ 513 bdl = (__le32 *)azx_dev->bdl.area; 514 ofs = 0; 515 azx_dev->frags = 0; 516 517 pos_adj = bus->bdl_pos_adj; 518 if (runtime && !azx_dev->no_period_wakeup && pos_adj > 0) { 519 pos_align = pos_adj; 520 pos_adj = DIV_ROUND_UP(pos_adj * runtime->rate, 48000); 521 if (!pos_adj) 522 pos_adj = pos_align; 523 else 524 pos_adj = roundup(pos_adj, pos_align); 525 pos_adj = frames_to_bytes(runtime, pos_adj); 526 if (pos_adj >= period_bytes) { 527 dev_warn(bus->dev, "Too big adjustment %d\n", 528 pos_adj); 529 pos_adj = 0; 530 } else { 531 ofs = setup_bdle(bus, dmab, azx_dev, 532 &bdl, ofs, pos_adj, true);

This is okay because runtime is set.

533 if (ofs < 0) 534 goto error; 535 } 536 } else 537 pos_adj = 0; 538 539 for (i = 0; i < periods; i++) { 540 if (i == periods - 1 && pos_adj) 541 ofs = setup_bdle(bus, dmab, azx_dev,

This is okay because pos_adj is checked.

542 &bdl, ofs, period_bytes - pos_adj, 0); 543 else 544 ofs = setup_bdle(bus, dmab, azx_dev, ^^^^ Potentially uninitialized?

545 &bdl, ofs, period_bytes, 546 !azx_dev->no_period_wakeup); 547 if (ofs < 0) 548 goto error; 549 } 550 return 0; 551 552 error: 553 dev_err(bus->dev, "Too many BDL entries: buffer=%d, period=%d\n", 554 azx_dev->bufsize, period_bytes); 555 return -EINVAL; 556 }

regards, dan carpenter