Hi,
serialsource.c does not have a maintainer attribution, so I'm posting this
here.
In TinyOS 2.0.x, the C SDK's serialsource.c contains a logic error in
write_serial_packet() that can cause a deadlock. This situation occurs when
write_serial_packet() is called by the host and the attached mote fails to
see the ending SYNC delimiter sent (due to a communication error). The host
waits in read_and_process() for an ack from the mote, and the mote waits in
RXSTATE_INFO for more data from the host. The deadlock is broken if the mote
forwards a radio packet to the host.
The patch below may be a suitable resolution.
Cheers,
Steve
Index: serialsource.c
===================================================================
--- serialsource.c (revision 1024)
+++ serialsource.c (working copy)
@@ -768,6 +768,9 @@
{
struct packet_list *entry;
+ if (source_wait(src, &deadline) < 0)
+ return 1;
+
read_and_process(src);
entry = pop_protocol_packet(src, P_ACK);
if (entry)
@@ -779,8 +782,6 @@
if (acked == src->send.seqno)
return 0;
}
- else if (source_wait(src, &deadline) < 0)
- return 1;
}
}
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