Hi Ricardo, url: https://github.com/intel-lab-lkp/linux/commits/Ricardo-Ribalda/media-uvc-Ignore-empty-TS-packets/20230109-180318 base: 73d6709376914f577a61bb29e596fa93ec66598c patch link: https://lore.kernel.org/r/20220920-resend-hwtimestamp-v4-1-a8ddc1358a29%40chromium.org patch subject: [PATCH v4 1/5] media: uvc: Ignore empty TS packets config: arc-randconfig-m031-20230108 compiler: arceb-elf-gcc (GCC) 12.1.0 If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Reported-by: Dan Carpenter <error27@xxxxxxxxx> smatch warnings: drivers/media/usb/uvc/uvc_video.c:538 uvc_video_clock_decode() error: we previously assumed 'buf' could be null (see line 514) vim +/buf +538 drivers/media/usb/uvc/uvc_video.c 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 469 static void 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 470 uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf, 2c6b222cee2d68e drivers/media/usb/uvc/uvc_video.c Laurent Pinchart 2018-01-16 471 const u8 *data, int len) 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 472 { 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 473 struct uvc_clock_sample *sample; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 474 unsigned int header_size; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 475 bool has_pts = false; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 476 bool has_scr = false; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 477 unsigned long flags; 828ee8c71950155 drivers/media/usb/uvc/uvc_video.c Arnd Bergmann 2017-11-27 478 ktime_t time; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 479 u16 host_sof; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 480 u16 dev_sof; febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 481 u32 dev_stc; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 482 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 483 switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) { 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 484 case UVC_STREAM_PTS | UVC_STREAM_SCR: 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 485 header_size = 12; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 486 has_pts = true; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 487 has_scr = true; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 488 break; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 489 case UVC_STREAM_PTS: 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 490 header_size = 6; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 491 has_pts = true; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 492 break; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 493 case UVC_STREAM_SCR: 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 494 header_size = 8; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 495 has_scr = true; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 496 break; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 497 default: 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 498 header_size = 2; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 499 break; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 500 } 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 501 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 502 /* Check for invalid headers. */ 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 503 if (len < header_size) 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 504 return; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 505 699b9a86a3f03ad drivers/media/usb/uvc/uvc_video.c Laurent Pinchart 2022-06-08 506 /* 699b9a86a3f03ad drivers/media/usb/uvc/uvc_video.c Laurent Pinchart 2022-06-08 507 * Extract the timestamps: 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 508 * 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 509 * - store the frame PTS in the buffer structure 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 510 * - if the SCR field is present, retrieve the host SOF counter and 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 511 * kernel timestamps and store them with the SCR STC and SOF fields 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 512 * in the ring buffer 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 513 */ 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 @514 if (has_pts && buf != NULL) ^^^^^^^^^^^ This code checks for NULL. 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 515 buf->pts = get_unaligned_le32(&data[2]); 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 516 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 517 if (!has_scr) 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 518 return; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 519 699b9a86a3f03ad drivers/media/usb/uvc/uvc_video.c Laurent Pinchart 2022-06-08 520 /* 699b9a86a3f03ad drivers/media/usb/uvc/uvc_video.c Laurent Pinchart 2022-06-08 521 * To limit the amount of data, drop SCRs with an SOF identical to the a919bd4d768164c drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-04 522 * previous one. This filtering is also needed to support UVC 1.5, where a919bd4d768164c drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-04 523 * all the data packets of the same frame contains the same SOF. In that a919bd4d768164c drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-04 524 * case only the first one will match the host_sof. 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 525 */ 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 526 dev_sof = get_unaligned_le16(&data[header_size - 2]); 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 527 if (dev_sof == stream->clock.last_sof) 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 528 return; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 529 febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 530 dev_stc = get_unaligned_le32(&data[header_size - 6]); febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 531 febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 532 /* febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 533 * Some devices make a borderline interpretation of the UVC 1.5 standard febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 534 * and sends packets with no data contain undefined timestamps. Ignore febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 535 * such packages to avoid interfering with the clock interpolation febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 536 * algorithm. febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 537 */ febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 @538 if (buf->bytesused == 0 && len == header_size && ^^^^^^^^^^^^^^ Unchecked dereference febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 539 dev_stc == 0 && dev_sof == 0) febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 540 return; febd4163e286059 drivers/media/usb/uvc/uvc_video.c Ricardo Ribalda 2023-01-09 541 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 542 stream->clock.last_sof = dev_sof; 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 543 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 544 host_sof = usb_get_current_frame_number(stream->dev->udev); 828ee8c71950155 drivers/media/usb/uvc/uvc_video.c Arnd Bergmann 2017-11-27 545 time = uvc_video_get_time(); 66847ef013cc4ed drivers/media/video/uvc/uvc_video.c Laurent Pinchart 2011-09-24 546 699b9a86a3f03ad drivers/media/usb/uvc/uvc_video.c Laurent Pinchart 2022-06-08 547 /* -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests
