connectd: don't crash if connect() fails immediately. #4360
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Took me a while (stressing under valgrind) to reproduce this,
then longer to figure out how it happened.
Turns out io_new_conn() can fail if the init function fails.
In our case, this can happen if connect() immediately returns
an error (inside io_connect). But we've already set the finish
function, which (if this was the last address), will free connect,
making the assignment
connect->conn = ...
write to a freed address.Either way, if it fails, try_connect_one_addr() has taken care to
update connect->conn, or free connect, and the caller should not do it.
Here's the valgrind trace:
Signed-off-by: Rusty Russell rusty@rustcorp.com.au
Fixes: #4343