sound/firewire/amdtp-stream.c:1099 process_rx_packets() error: uninitialized symbol 'curr_cycle_time'.

From: Dan Carpenter
Date: Mon Jul 03 2023 - 09:00:23 EST

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: b25f62ccb490680a8cee755ac4528909395e0711
commit: fef4e61b0b765b6d22badcd5b6575b159e7d510a ALSA: firewire-lib: extend tracepoints event including CYCLE_TIME of 1394 OHCI
config: i386-randconfig-m021-20230701 (https://download.01.org/0day-ci/archive/20230701/202307011324.jFJ96dTo-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230701/202307011324.jFJ96dTo-lkp@xxxxxxxxx/reproduce)

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 <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202307011324.jFJ96dTo-lkp@xxxxxxxxx/

New smatch warnings:
sound/firewire/amdtp-stream.c:1099 process_rx_packets() error: uninitialized symbol 'curr_cycle_time'.

Old smatch warnings:
sound/firewire/amdtp-stream.c:944 generate_tx_packet_descs() error: uninitialized symbol 'curr_cycle_time'.

vim +/curr_cycle_time +1099 sound/firewire/amdtp-stream.c

9b1fcd9bf80206 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1047 static void process_rx_packets(struct fw_iso_context *context, u32 tstamp, size_t header_length,
9b1fcd9bf80206 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1048 void *header, void *private_data)
0f5cfcb24d9c93 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1049 {
0f5cfcb24d9c93 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1050 struct amdtp_stream *s = private_data;
69efd5c4bd4c0e sound/firewire/amdtp-stream.c Takashi Sakamoto 2020-05-08 1051 const struct amdtp_domain *d = s->domain;
0f5cfcb24d9c93 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1052 const __be32 *ctx_header = header;
9b1fcd9bf80206 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1053 const unsigned int events_per_period = d->events_per_period;
60dd49298ec580 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1054 unsigned int event_count = s->ctx_data.rx.event_count;
f0117128879be6 sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-09 1055 struct pkt_desc *desc = s->packet_descs_cursor;
233dbbc7af5d27 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1056 unsigned int pkt_header_length;
a0e023317e2d55 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1057 unsigned int packets;
fef4e61b0b765b sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-10 1058 u32 curr_cycle_time;
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1059 bool need_hw_irq;
0f5cfcb24d9c93 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1060 int i;
0f5cfcb24d9c93 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1061
0f5cfcb24d9c93 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1062 if (s->packet_index < 0)
0f5cfcb24d9c93 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1063 return;
0f5cfcb24d9c93 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1064
a0e023317e2d55 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1065 // Calculate the number of packets in buffer and check XRUN.
a0e023317e2d55 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1066 packets = header_length / sizeof(*ctx_header);
a0e023317e2d55 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1067
cec371ff1ab18d sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-09 1068 generate_rx_packet_descs(s, desc, ctx_header, packets);
0f5cfcb24d9c93 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1069
cec371ff1ab18d sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-09 1070 process_ctx_payloads(s, desc, packets);
5e2ece0fdceb02 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1071
233dbbc7af5d27 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1072 if (!(s->flags & CIP_NO_HEADER))
233dbbc7af5d27 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1073 pkt_header_length = IT_PKT_HEADER_SIZE_CIP;
233dbbc7af5d27 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1074 else
233dbbc7af5d27 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1075 pkt_header_length = 0;
233dbbc7af5d27 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1076
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1077 if (s == d->irq_target) {
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1078 // At NO_PERIOD_WAKEUP mode, the packets for all IT/IR contexts are processed by
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1079 // the tasks of user process operating ALSA PCM character device by calling ioctl(2)
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1080 // with some requests, instead of scheduled hardware IRQ of an IT context.
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1081 struct snd_pcm_substream *pcm = READ_ONCE(s->pcm);
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1082 need_hw_irq = !pcm || !pcm->runtime->no_period_wakeup;
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1083 } else {
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1084 need_hw_irq = false;
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1085 }
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1086
fef4e61b0b765b sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-10 1087 if (trace_amdtp_packet_enabled())
fef4e61b0b765b sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-10 1088 (void)fw_card_read_cycle_time(fw_parent_device(s->unit)->card, &curr_cycle_time);

If trace_amdtp_packet_enabled() is false then curr_cycle_time is
uninitialized.

fef4e61b0b765b sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-10 1089
5e2ece0fdceb02 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1090 for (i = 0; i < packets; ++i) {
6bc1a2699b79d7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-05-24 1091 struct {
6bc1a2699b79d7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-05-24 1092 struct fw_iso_packet params;
67d92ee7a50b00 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1093 __be32 header[CIP_HEADER_QUADLETS];
6bc1a2699b79d7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-05-24 1094 } template = { {0}, {0} };
e229853d505d7a sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1095 bool sched_irq = false;
6bc1a2699b79d7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-05-24 1096
233dbbc7af5d27 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-20 1097 build_it_pkt_header(s, desc->cycle, &template.params, pkt_header_length,
f4f6ae7b7c1fdb sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-07-22 1098 desc->data_blocks, desc->data_block_counter,
fef4e61b0b765b sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-10 @1099 desc->syt, i, curr_cycle_time);

The curr_cycle_time variable is only going to be used if trace_amdtp_packet_enabled()
is true. We would consider it a false positive if build_it_pkt_header()
is inlined but a bug if it's not. (Technically passing uninitialized
data is undefined behavior but if a function is inlined then it's not
"passing" anything).

31ef9134eb5263 sound/firewire/amdtp.c Clemens Ladisch 2011-03-15 1100
2472cfb3232caf sound/firewire/amdtp-stream.c Takashi Sakamoto 2020-05-08 1101 if (s == s->domain->irq_target) {
e229853d505d7a sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1102 event_count += desc->data_blocks;
e229853d505d7a sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1103 if (event_count >= events_per_period) {
e229853d505d7a sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1104 event_count -= events_per_period;
d360870a5bcff7 sound/firewire/amdtp-stream.c Takashi Sakamoto 2021-05-27 1105 sched_irq = need_hw_irq;
e229853d505d7a sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1106 }
60dd49298ec580 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1107 }
e229853d505d7a sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1108
e229853d505d7a sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1109 if (queue_out_packet(s, &template.params, sched_irq) < 0) {
fce9b013fee94d sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-05-21 1110 cancel_stream(s);
a4103bd7fdd595 sound/firewire/amdtp.c Takashi Sakamoto 2015-05-22 1111 return;
ccccad8646fad5 sound/firewire/amdtp.c Takashi Sakamoto 2014-04-25 1112 }
cec371ff1ab18d sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-09 1113
cec371ff1ab18d sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-09 1114 desc = amdtp_stream_next_packet_desc(s, desc);
a4103bd7fdd595 sound/firewire/amdtp.c Takashi Sakamoto 2015-05-22 1115 }
a4103bd7fdd595 sound/firewire/amdtp.c Takashi Sakamoto 2015-05-22 1116
60dd49298ec580 sound/firewire/amdtp-stream.c Takashi Sakamoto 2019-10-18 1117 s->ctx_data.rx.event_count = event_count;
f0117128879be6 sound/firewire/amdtp-stream.c Takashi Sakamoto 2023-01-09 1118 s->packet_descs_cursor = desc;
31ef9134eb5263 sound/firewire/amdtp.c Clemens Ladisch 2011-03-15 1119 }

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