Hello Takashi Sakamoto,
The patch fef4e61b0b76: "ALSA: firewire-lib: extend tracepoints event including CYCLE_TIME of 1394 OHCI" from Jan 10, 2023, leads to the following Smatch static checker warning:
sound/firewire/amdtp-stream.c:944 generate_tx_packet_descs() error: uninitialized symbol 'curr_cycle_time'. sound/firewire/amdtp-stream.c:1099 process_rx_packets() error: uninitialized symbol 'curr_cycle_time'.
sound/firewire/amdtp-stream.c 1047 static void process_rx_packets(struct fw_iso_context *context, u32 tstamp, size_t header_length, 1048 void *header, void *private_data) 1049 { 1050 struct amdtp_stream *s = private_data; 1051 const struct amdtp_domain *d = s->domain; 1052 const __be32 *ctx_header = header; 1053 const unsigned int events_per_period = d->events_per_period; 1054 unsigned int event_count = s->ctx_data.rx.event_count; 1055 struct pkt_desc *desc = s->packet_descs_cursor; 1056 unsigned int pkt_header_length; 1057 unsigned int packets; 1058 u32 curr_cycle_time; ^^^^^^^^^^^^^^^^^^^
1059 bool need_hw_irq; 1060 int i; 1061 1062 if (s->packet_index < 0) 1063 return; 1064 1065 // Calculate the number of packets in buffer and check XRUN. 1066 packets = header_length / sizeof(*ctx_header); 1067 1068 generate_rx_packet_descs(s, desc, ctx_header, packets); 1069 1070 process_ctx_payloads(s, desc, packets); 1071 1072 if (!(s->flags & CIP_NO_HEADER)) 1073 pkt_header_length = IT_PKT_HEADER_SIZE_CIP; 1074 else 1075 pkt_header_length = 0; 1076 1077 if (s == d->irq_target) { 1078 // At NO_PERIOD_WAKEUP mode, the packets for all IT/IR contexts are processed by 1079 // the tasks of user process operating ALSA PCM character device by calling ioctl(2) 1080 // with some requests, instead of scheduled hardware IRQ of an IT context. 1081 struct snd_pcm_substream *pcm = READ_ONCE(s->pcm); 1082 need_hw_irq = !pcm || !pcm->runtime->no_period_wakeup; 1083 } else { 1084 need_hw_irq = false; 1085 } 1086 1087 if (trace_amdtp_packet_enabled()) 1088 (void)fw_card_read_cycle_time(fw_parent_device(s->unit)->card, &curr_cycle_time);
No error checking and no else path.
1089 1090 for (i = 0; i < packets; ++i) { 1091 struct { 1092 struct fw_iso_packet params; 1093 __be32 header[CIP_HEADER_QUADLETS]; 1094 } template = { {0}, {0} }; 1095 bool sched_irq = false; 1096 1097 build_it_pkt_header(s, desc->cycle, &template.params, pkt_header_length, 1098 desc->data_blocks, desc->data_block_counter, --> 1099 desc->syt, i, curr_cycle_time); ^^^^^^^^^^^^^^^ Uninitialized.
1100 1101 if (s == s->domain->irq_target) { 1102 event_count += desc->data_blocks; 1103 if (event_count >= events_per_period) { 1104 event_count -= events_per_period; 1105 sched_irq = need_hw_irq; 1106 } 1107 } 1108 1109 if (queue_out_packet(s, &template.params, sched_irq) < 0) { 1110 cancel_stream(s); 1111 return; 1112 } 1113 1114 desc = amdtp_stream_next_packet_desc(s, desc); 1115 } 1116 1117 s->ctx_data.rx.event_count = event_count; 1118 s->packet_descs_cursor = desc; 1119 }
regards, dan carpenter