[PATCH net-next 1/2] selftests: net: make the dump test less sensitive to mem accounting

[PATCH net-next 1/2] selftests: net: make the dump test less sensitive to mem accounting

[Jakub Kicinski]

Recent changes to make netlink socket memory accounting must
have broken the implicit assumption of the netlink-dump test
that we can fit exactly 64 dumps into the socket. Handle the
failure mode properly, and increase the dump count to 80
to make sure we still run into the error condition if
the default buffer size increases in the future.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 tools/testing/selftests/net/netlink-dumps.c | 43 ++++++++++++++++-----
 1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/net/netlink-dumps.c b/tools/testing/selftests/net/netlink-dumps.c
index 07423f256f96..7618ebe528a4 100644
--- a/tools/testing/selftests/net/netlink-dumps.c
+++ b/tools/testing/selftests/net/netlink-dumps.c
@@ -31,9 +31,18 @@ struct ext_ack {
 	const char *str;
 };
 
-/* 0: no done, 1: done found, 2: extack found, -1: error */
-static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
+enum get_ea_ret {
+	ERROR = -1,
+	NO_CTRL = 0,
+	FOUND_DONE,
+	FOUND_ERR,
+	FOUND_EXTACK,
+};
+
+static enum get_ea_ret
+nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
 {
+	enum get_ea_ret ret = NO_CTRL;
 	const struct nlmsghdr *nlh;
 	const struct nlattr *attr;
 	ssize_t rem;
@@ -41,15 +50,19 @@ static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
 	for (rem = n; rem > 0; NLMSG_NEXT(nlh, rem)) {
 		nlh = (struct nlmsghdr *)&buf[n - rem];
 		if (!NLMSG_OK(nlh, rem))
-			return -1;
+			return ERROR;
 
-		if (nlh->nlmsg_type != NLMSG_DONE)
+		if (nlh->nlmsg_type == NLMSG_ERROR)
+			ret = FOUND_ERR;
+		else if (nlh->nlmsg_type == NLMSG_DONE)
+			ret = FOUND_DONE;
+		else
 			continue;
 
 		ea->err = -*(int *)NLMSG_DATA(nlh);
 
 		if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS))
-			return 1;
+			return ret;
 
 		ynl_attr_for_each(attr, nlh, sizeof(int)) {
 			switch (ynl_attr_type(attr)) {
@@ -68,10 +81,10 @@ static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
 			}
 		}
 
-		return 2;
+		return FOUND_EXTACK;
 	}
 
-	return 0;
+	return ret;
 }
 
 static const struct {
@@ -99,9 +112,9 @@ static const struct {
 TEST(dump_extack)
 {
 	int netlink_sock;
+	int i, cnt, ret;
 	char buf[8192];
 	int one = 1;
-	int i, cnt;
 	ssize_t n;
 
 	netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
@@ -118,7 +131,7 @@ TEST(dump_extack)
 	ASSERT_EQ(n, 0);
 
 	/* Dump so many times we fill up the buffer */
-	cnt = 64;
+	cnt = 80;
 	for (i = 0; i < cnt; i++) {
 		n = send(netlink_sock, &dump_neigh_bad,
 			 sizeof(dump_neigh_bad), 0);
@@ -140,10 +153,20 @@ TEST(dump_extack)
 		}
 		ASSERT_GE(n, (ssize_t)sizeof(struct nlmsghdr));
 
-		EXPECT_EQ(nl_get_extack(buf, n, &ea), 2);
+		ret = nl_get_extack(buf, n, &ea);
+		/* Once we fill the buffer we'll see one ENOBUFS followed
+		 * by a number of EBUSYs. Then the last recv() will finally
+		 * trigger and complete the dump.
+		 */
+		if (ret == FOUND_ERR && (ea.err == ENOBUFS || ea.err == EBUSY))
+			continue;
+		EXPECT_EQ(ret, FOUND_EXTACK);
+		EXPECT_EQ(ea.err, EINVAL);
 		EXPECT_EQ(ea.attr_offs,
 			  sizeof(struct nlmsghdr) + sizeof(struct ndmsg));
 	}
+	/* Make sure last message was a full DONE+extack */
+	EXPECT_EQ(ret, FOUND_EXTACK);
 }
 
 static const struct {
-- 
2.51.0

[PATCH net-next 2/2] selftests: net: move netlink-dumps back to progs

[Jakub Kicinski]

Commit 9bb88c659673 ("selftests: net: test extacks in netlink dumps")
moved netlink-dumps from TEST_GEN_PROGS to YNL_GEN_FILES.
But _FILES are not for tests, rather for utilities / helpers.
Create YNL_GEN_PROGS and include netlink-dumps there.
This makes netlink-dumps part of executed tests, again.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 tools/testing/selftests/net/Makefile | 4 +++-
 tools/testing/selftests/net/ynl.mk   | 5 +++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 9926a14fd279..8c860782f9cd 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -121,8 +121,10 @@ TEST_PROGS += ipv6_force_forwarding.sh
 TEST_PROGS += route_hint.sh
 
 # YNL files, must be before "include ..lib.mk"
-YNL_GEN_FILES := busy_poller netlink-dumps
+YNL_GEN_FILES := busy_poller
+YNL_GEN_PROGS := netlink-dumps
 TEST_GEN_FILES += $(YNL_GEN_FILES)
+TEST_GEN_PROGS += $(YNL_GEN_PROGS)
 
 TEST_FILES := settings
 TEST_FILES += in_netns.sh lib.sh setup_loopback.sh setup_veth.sh
diff --git a/tools/testing/selftests/net/ynl.mk b/tools/testing/selftests/net/ynl.mk
index e907c2751956..793a2fc33d9f 100644
--- a/tools/testing/selftests/net/ynl.mk
+++ b/tools/testing/selftests/net/ynl.mk
@@ -5,10 +5,11 @@
 # Inputs:
 #
 # YNL_GENS:      families we need in the selftests
-# YNL_PROGS:     TEST_PROGS which need YNL (TODO, none exist, yet)
+# YNL_GEN_PROGS: TEST_GEN_PROGS which need YNL
 # YNL_GEN_FILES: TEST_GEN_FILES which need YNL
 
-YNL_OUTPUTS := $(patsubst %,$(OUTPUT)/%,$(YNL_GEN_FILES))
+YNL_OUTPUTS :=	$(patsubst %,$(OUTPUT)/%,$(YNL_GEN_FILES)) \
+		$(patsubst %,$(OUTPUT)/%,$(YNL_GEN_PROGS))
 YNL_SPECS := \
 	$(patsubst %,$(top_srcdir)/Documentation/netlink/specs/%.yaml,$(YNL_GENS))
 
-- 
2.51.0

Re: [PATCH net-next 1/2] selftests: net: make the dump test less sensitive to mem accounting

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Sat,  6 Sep 2025 14:13:50 -0700 you wrote:
> Recent changes to make netlink socket memory accounting must
> have broken the implicit assumption of the netlink-dump test
> that we can fit exactly 64 dumps into the socket. Handle the
> failure mode properly, and increase the dump count to 80
> to make sure we still run into the error condition if
> the default buffer size increases in the future.
> 
> [...]

Here is the summary with links:
  - [net-next,1/2] selftests: net: make the dump test less sensitive to mem accounting
    https://git.kernel.org/netdev/net-next/c/27bc5eaf004c
  - [net-next,2/2] selftests: net: move netlink-dumps back to progs
    https://git.kernel.org/netdev/net-next/c/f3883b1ea5a8

You are awesome, thank you!
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