tools/testing/selftests/net/mptcp/Makefile | 4 ++++ tools/testing/selftests/net/mptcp/mptcp_connect.c | 3 ++- tools/testing/selftests/net/mptcp/mptcp_inq.c | 3 ++- tools/testing/selftests/net/mptcp/mptcp_sockopt.c | 3 ++- 4 files changed, 10 insertions(+), 3 deletions(-)
Compiler reports potential uses of uninitialized variables in
mptcp_connect.c when xerror() is called from failure paths.
mptcp_connect.c:1262:11: warning: variable 'raw_addr' is used
uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]
xerror() terminates execution by calling exit(), but it is not visible
to the compiler & assumes control flow may continue past the call.
Annotate xerror() with __noreturn so the compiler can correctly reason
about control flow and avoid false-positive uninitialized variable
warnings.
Signed-off-by: Ankit Khushwaha <ankitkhushwaha.linux@gmail.com>
---
changelog:
v2:
- annotate 'xerror()' with __noreturn
- remove defining 'raw_addr' to NULL
v1: https://lore.kernel.org/all/20251126163046.58615-1-ankitkhushwaha.linux@gmail.com/
---
tools/testing/selftests/net/mptcp/Makefile | 4 ++++
tools/testing/selftests/net/mptcp/mptcp_connect.c | 3 ++-
tools/testing/selftests/net/mptcp/mptcp_inq.c | 3 ++-
tools/testing/selftests/net/mptcp/mptcp_sockopt.c | 3 ++-
4 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/net/mptcp/Makefile b/tools/testing/selftests/net/mptcp/Makefile
index 15d144a25d82..4c94c01b893a 100644
--- a/tools/testing/selftests/net/mptcp/Makefile
+++ b/tools/testing/selftests/net/mptcp/Makefile
@@ -35,3 +35,7 @@ TEST_INCLUDES := ../lib.sh $(wildcard ../lib/sh/*.sh)
EXTRA_CLEAN := *.pcap
include ../../lib.mk
+
+$(OUTPUT)/mptcp_connect: CFLAGS += -I$(top_srcdir)/tools/include
+$(OUTPUT)/mptcp_sockopt: CFLAGS += -I$(top_srcdir)/tools/include
+$(OUTPUT)/mptcp_inq: CFLAGS += -I$(top_srcdir)/tools/include
diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.c b/tools/testing/selftests/net/mptcp/mptcp_connect.c
index 404a77bf366a..10f6f99cfd4e 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_connect.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_connect.c
@@ -33,6 +33,7 @@
#include <linux/tcp.h>
#include <linux/time_types.h>
#include <linux/sockios.h>
+#include <linux/compiler.h>
extern int optind;
@@ -140,7 +141,7 @@ static void die_usage(void)
exit(1);
}
-static void xerror(const char *fmt, ...)
+static void __noreturn xerror(const char *fmt, ...)
{
va_list ap;
diff --git a/tools/testing/selftests/net/mptcp/mptcp_inq.c b/tools/testing/selftests/net/mptcp/mptcp_inq.c
index 8e8f6441ad8b..d4a729814662 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_inq.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_inq.c
@@ -28,6 +28,7 @@
#include <linux/tcp.h>
#include <linux/sockios.h>
+#include <linux/compiler.h>
#ifndef IPPROTO_MPTCP
#define IPPROTO_MPTCP 262
@@ -52,7 +53,7 @@ static void die_usage(int r)
exit(r);
}
-static void xerror(const char *fmt, ...)
+static void __noreturn xerror(const char *fmt, ...)
{
va_list ap;
diff --git a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c b/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
index 286164f7246e..15cea5e919b5 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
@@ -25,6 +25,7 @@
#include <netinet/in.h>
#include <linux/tcp.h>
+#include <linux/compiler.h>
static int pf = AF_INET;
@@ -139,7 +140,7 @@ static void die_usage(int r)
exit(r);
}
-static void xerror(const char *fmt, ...)
+static void __noreturn xerror(const char *fmt, ...)
{
va_list ap;
--
2.52.0Hi Ankit, On 29/11/2025 05:38, Ankit Khushwaha wrote: > Compiler reports potential uses of uninitialized variables in > mptcp_connect.c when xerror() is called from failure paths. > > mptcp_connect.c:1262:11: warning: variable 'raw_addr' is used > uninitialized whenever 'if' condition is false > [-Wsometimes-uninitialized] > > xerror() terminates execution by calling exit(), but it is not visible > to the compiler & assumes control flow may continue past the call. > > Annotate xerror() with __noreturn so the compiler can correctly reason > about control flow and avoid false-positive uninitialized variable > warnings. > > Signed-off-by: Ankit Khushwaha <ankitkhushwaha.linux@gmail.com> > --- > changelog: > v2: > - annotate 'xerror()' with __noreturn > - remove defining 'raw_addr' to NULL Thank you for the new version! Note: this patch can target 'net' instead of 'net-next'. > --- > tools/testing/selftests/net/mptcp/Makefile | 4 ++++ > tools/testing/selftests/net/mptcp/mptcp_connect.c | 3 ++- > tools/testing/selftests/net/mptcp/mptcp_inq.c | 3 ++- > tools/testing/selftests/net/mptcp/mptcp_sockopt.c | 3 ++- Good idea to fix the other tools too! > 4 files changed, 10 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/net/mptcp/Makefile b/tools/testing/selftests/net/mptcp/Makefile > index 15d144a25d82..4c94c01b893a 100644 > --- a/tools/testing/selftests/net/mptcp/Makefile > +++ b/tools/testing/selftests/net/mptcp/Makefile > @@ -35,3 +35,7 @@ TEST_INCLUDES := ../lib.sh $(wildcard ../lib/sh/*.sh) > EXTRA_CLEAN := *.pcap > > include ../../lib.mk > + > +$(OUTPUT)/mptcp_connect: CFLAGS += -I$(top_srcdir)/tools/include > +$(OUTPUT)/mptcp_sockopt: CFLAGS += -I$(top_srcdir)/tools/include > +$(OUTPUT)/mptcp_inq: CFLAGS += -I$(top_srcdir)/tools/include Small detail: I think you can simply append the "main" CFLAGS at the top of the file instead of adding specific rules per tool. Note: because the CFLAGS variable is already long, please split it like it is done in tools/testing/selftests/net/Makefile. While at it, do you mind adding __noreturn to die_perror() in mptcp_diag.c mptcp_inq.c mptcp_sockopt.c as well please? Cheers, Matt -- Sponsored by the NGI0 Core fund.
On Sat, 29 Nov 2025 19:13:08 +0100 Matthieu Baerts wrote: > > +$(OUTPUT)/mptcp_connect: CFLAGS += -I$(top_srcdir)/tools/include > > +$(OUTPUT)/mptcp_sockopt: CFLAGS += -I$(top_srcdir)/tools/include > > +$(OUTPUT)/mptcp_inq: CFLAGS += -I$(top_srcdir)/tools/include I believe this is being added via MM or kselftest tree at level of the main ksft makefile. Since this is a false positive, maybe let's defer fixing the issue until after the merge window? When the -I.. flag will be implicitly in place?
Hi Jakub, Ankit, On 30/11/2025 02:41, Jakub Kicinski wrote: > On Sat, 29 Nov 2025 19:13:08 +0100 Matthieu Baerts wrote: >>> +$(OUTPUT)/mptcp_connect: CFLAGS += -I$(top_srcdir)/tools/include >>> +$(OUTPUT)/mptcp_sockopt: CFLAGS += -I$(top_srcdir)/tools/include >>> +$(OUTPUT)/mptcp_inq: CFLAGS += -I$(top_srcdir)/tools/include > > I believe this is being added via MM or kselftest tree at level of the > main ksft makefile. Since this is a false positive, maybe let's defer > fixing the issue until after the merge window? When the -I.. flag > will be implicitly in place? @Jakub: Thank you for sharing this, I didn't know about that. That makes sense to wait. @Ankit: do you mind sending a v3 without the modifications of the Makefile, and supporting die_perror() in a bit more than 2 weeks or later, please? Cheers, Matt -- Sponsored by the NGI0 Core fund.
Hi Matthieu, Jakub, On Sun, Nov 30, 2025 at 06:09:18PM +0100, Matthieu Baerts wrote: > Hi Jakub, Ankit, > > On 30/11/2025 02:41, Jakub Kicinski wrote: > > On Sat, 29 Nov 2025 19:13:08 +0100 Matthieu Baerts wrote: > >>> +$(OUTPUT)/mptcp_connect: CFLAGS += -I$(top_srcdir)/tools/include > >>> +$(OUTPUT)/mptcp_sockopt: CFLAGS += -I$(top_srcdir)/tools/include > >>> +$(OUTPUT)/mptcp_inq: CFLAGS += -I$(top_srcdir)/tools/include > > > > I believe this is being added via MM or kselftest tree at level of the > > main ksft makefile. Since this is a false positive, maybe let's defer > > fixing the issue until after the merge window? When the -I.. flag > > will be implicitly in place? > > @Ankit: do you mind sending a v3 without the modifications of the > Makefile, and supporting die_perror() in a bit more than 2 weeks or > later, please? I will surely send v3 patch after merge window with the requested changes. Thanks, -- Ankit
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