diff --git a/ccan/README b/ccan/README
index 7f367f1cf..8f5f06078 100644
--- a/ccan/README
+++ b/ccan/README
@@ -1,3 +1,3 @@
 CCAN imported from http://ccodearchive.net.
 
-CCAN version: init-2573-g882a1ac0
+CCAN version: init-2575-g3beff01a
diff --git a/ccan/ccan/rune/coding.c b/ccan/ccan/rune/coding.c
index f4d110283..495d37c34 100644
--- a/ccan/ccan/rune/coding.c
+++ b/ccan/ccan/rune/coding.c
@@ -206,7 +206,7 @@ bool rune_condition_is_valid(enum rune_condition cond)
 size_t rune_altern_fieldname_len(const char *alternstr, size_t alternstrlen)
 {
 	for (size_t i = 0; i < alternstrlen; i++) {
-		if (cispunct(alternstr[i]))
+		if (cispunct(alternstr[i]) && alternstr[i] != '_')
 			return i;
 	}
 	return alternstrlen;
diff --git a/ccan/ccan/rune/test/run.c b/ccan/ccan/rune/test/run.c
index e53265528..d90b701c6 100644
--- a/ccan/ccan/rune/test/run.c
+++ b/ccan/ccan/rune/test/run.c
@@ -43,7 +43,7 @@ int main(void)
 	assert(vecs);
 	lines = tal_strsplit(mr, take(vecs), "\n", STR_NO_EMPTY);
 
-	plan_tests(343);
+	plan_tests(355);
 
 	for (size_t i = 0; lines[i]; i++) {
 		struct rune *rune1, *rune2;
diff --git a/ccan/ccan/rune/test/test_vectors.csv b/ccan/ccan/rune/test/test_vectors.csv
index a8411693c..880ea3c69 100644
--- a/ccan/ccan/rune/test/test_vectors.csv
+++ b/ccan/ccan/rune/test/test_vectors.csv
@@ -94,6 +94,12 @@ PASS,f1=
 PASS,f1=/
 PASS,f1=11
 PASS
+VALID,f_with_underscores equals v1,ee979e1f2c376d69923aab0e8e001111963af038bdce394ffd7ecdc9e7020a6e:f_with_underscores=v1,7peeHyw3bWmSOqsOjgAREZY68Di9zjlP_X7NyecCCm5mX3dpdGhfdW5kZXJzY29yZXM9djE=
+PASS,f_with_underscores=v1
+FAIL,f_with_underscores=v
+FAIL,f_with_underscores=v1a
+FAIL
+FAIL,f2=f_with_underscores
 VALID,f1=1 or f2=3,85c3643dc102f0a0d6f20eeb8c294092151688fae41ef7c8ec7272ab23918376:f1=1|f2=3,hcNkPcEC8KDW8g7rjClAkhUWiPrkHvfI7HJyqyORg3ZmMT0xfGYyPTM=
 PASS,f1=1
 PASS,f1=1,f2=2
@@ -144,7 +150,6 @@ MALFORMED,Bad condition ?,76bdd625de0e12058956e6c8a07cac58d7dc2253609a6bfb959f87
 MALFORMED,Bad condition [,76bdd625de0e12058956e6c8a07cac58d7dc2253609a6bfb959f87cc094f3f0f:f1[11,dr3WJd4OEgWJVubIoHysWNfcIlNgmmv7lZ-HzAlPPw9mMVsxMQ==
 MALFORMED,Bad condition \,76bdd625de0e12058956e6c8a07cac58d7dc2253609a6bfb959f87cc094f3f0f:f1\11,dr3WJd4OEgWJVubIoHysWNfcIlNgmmv7lZ-HzAlPPw9mMVwxMQ==
 MALFORMED,Bad condition ],76bdd625de0e12058956e6c8a07cac58d7dc2253609a6bfb959f87cc094f3f0f:f1]11,dr3WJd4OEgWJVubIoHysWNfcIlNgmmv7lZ-HzAlPPw9mMV0xMQ==
-MALFORMED,Bad condition _,76bdd625de0e12058956e6c8a07cac58d7dc2253609a6bfb959f87cc094f3f0f:f1_11,dr3WJd4OEgWJVubIoHysWNfcIlNgmmv7lZ-HzAlPPw9mMV8xMQ==
 MALFORMED,Bad condition `,76bdd625de0e12058956e6c8a07cac58d7dc2253609a6bfb959f87cc094f3f0f:f1`11,dr3WJd4OEgWJVubIoHysWNfcIlNgmmv7lZ-HzAlPPw9mMWAxMQ==
 MALFORMED,Bad condition |,76bdd625de0e12058956e6c8a07cac58d7dc2253609a6bfb959f87cc094f3f0f:f1|11,dr3WJd4OEgWJVubIoHysWNfcIlNgmmv7lZ-HzAlPPw9mMXwxMQ==
 BAD DERIVATION,Incremented sha,76bdd625de0e12058956e6c8a07cac58d7dc2253609a6bfb959f87cc094f3f0e:f1#11,dr3WJd4OEgWJVubIoHysWNfcIlNgmmv7lZ-HzAlPPw5mMSMxMQ==
diff --git a/ccan/tools/configurator/configurator.c b/ccan/tools/configurator/configurator.c
index 722a6f692..7d8f6b095 100644
--- a/ccan/tools/configurator/configurator.c
+++ b/ccan/tools/configurator/configurator.c
@@ -471,7 +471,7 @@ static const struct test base_tests[] = {
 	  "#include <stddef.h>\n"
 	  "#include <ucontext.h>\n"
 	  "static int worked = 0;\n"
-	  "static char stack[1024];\n"
+	  "static char stack[8192];\n"
 	  "static ucontext_t a, b;\n"
 	  "static void fn(void *p, void *q) {\n"
 	  "	void *cp = &worked;\n"