This series fixes build warnings and errors observed when trying to build selftests.
v2: Emphasize that the patch series fixes build warnings and errors which are seen even if -Werror is not provided. Fix usage of cc-option. For "ignoring return value" warnings, use perror() to display an error message if the affected function returns an error.
---------------------------------------------------------------- Guenter Roeck (13): clone3: clone3_cap_checkpoint_restore: Fix build warnings selftests: ntsync: Fix build warnings selftests/filesystems: fclog: Fix build warnings and errors selftests/filesystems: file_stressor: Fix build warning selftests/filesystems: anon_inode_test: Fix build warning selftest: af_unix: Support compilers without flex-array-member-not-at-end support selftest/futex: Comment out test_futex_mpol selftests: net: netlink-dumps: Avoid uninitialized variable warning selftests/seccomp: Fix build warning selftests: net: Fix build warnings selftests/fs/mount-notify: Fix build warning selftests/fs/mount-notify-ns: Fix build warning selftests: net: tfo: Fix build warning
tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c | 4 ---- tools/testing/selftests/drivers/ntsync/ntsync.c | 4 ++-- tools/testing/selftests/filesystems/anon_inode_test.c | 1 + tools/testing/selftests/filesystems/fclog.c | 1 + tools/testing/selftests/filesystems/file_stressor.c | 2 -- .../testing/selftests/filesystems/mount-notify/mount-notify_test.c | 3 ++- .../selftests/filesystems/mount-notify/mount-notify_test_ns.c | 3 ++- tools/testing/selftests/futex/functional/futex_numa_mpol.c | 2 ++ tools/testing/selftests/net/af_unix/Makefile | 7 ++++++- tools/testing/selftests/net/lib/ksft.h | 6 ++++-- tools/testing/selftests/net/netlink-dumps.c | 2 +- tools/testing/selftests/net/tfo.c | 3 ++- tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++- 13 files changed, 25 insertions(+), 16 deletions(-)
Fix:
clone3_cap_checkpoint_restore.c:56:7: warning: unused variable 'ret' 56 | int ret; | ^~~ clone3_cap_checkpoint_restore.c:57:8: warning: unused variable 'tmp' 57 | char tmp = 0; | ^~~ clone3_cap_checkpoint_restore.c:138:6: warning: unused variable 'ret' 138 | int ret = 0;
by removing the unused variables.
Fixes: 1d27a0be16d6 ("selftests: add clone3() CAP_CHECKPOINT_RESTORE test") Cc: Adrian Reber areber@redhat.com Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes build warnings
.../testing/selftests/clone3/clone3_cap_checkpoint_restore.c | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c b/tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c index 3c196fa86c99..976e92c259fc 100644 --- a/tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c +++ b/tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c @@ -53,9 +53,6 @@ static int call_clone3_set_tid(struct __test_metadata *_metadata, }
if (pid == 0) { - int ret; - char tmp = 0; - TH_LOG("I am the child, my PID is %d (expected %d)", getpid(), set_tid[0]);
if (set_tid[0] != getpid()) @@ -135,7 +132,6 @@ TEST(clone3_cap_checkpoint_restore) { pid_t pid; int status; - int ret = 0; pid_t set_tid[1];
test_clone3_supported();
Fix
ntsync.c:1286:20: warning: call to undeclared function 'gettid'; ISO C99 and later do not support implicit function declarations 1286 | wait_args.owner = gettid(); | ^ ntsync.c:1280:8: warning: unused variable 'index' 1280 | __u32 index, count, i; | ^~~~~ ntsync.c:1281:6: warning: unused variable 'ret' 1281 | int ret;
by adding the missing include file and removing the unused variables.
Fixes: a22860e57b54 ("selftests: ntsync: Add a stress test for contended waits.") Cc: Elizabeth Figura zfigura@codeweavers.com Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes build warnings
tools/testing/selftests/drivers/ntsync/ntsync.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c index 3aad311574c4..d3df94047e4d 100644 --- a/tools/testing/selftests/drivers/ntsync/ntsync.c +++ b/tools/testing/selftests/drivers/ntsync/ntsync.c @@ -11,6 +11,7 @@ #include <fcntl.h> #include <time.h> #include <pthread.h> +#include <unistd.h> #include <linux/ntsync.h> #include "../../kselftest_harness.h"
@@ -1277,8 +1278,7 @@ static int stress_device, stress_start_event, stress_mutex; static void *stress_thread(void *arg) { struct ntsync_wait_args wait_args = {0}; - __u32 index, count, i; - int ret; + __u32 count, i;
wait_args.timeout = UINT64_MAX; wait_args.count = 1;
Fix
fclog.c:37:21: warning: call to undeclared function 'open' fclog.c:37:47: error: use of undeclared identifier 'O_RDONLY'; did you mean 'MS_RDONLY'? fclog.c:37:56: error: use of undeclared identifier 'O_CLOEXEC'
by including fcntl.h.
Fixes: df579e471111b ("selftests/filesystems: add basic fscontext log tests") Cc: Aleksa Sarai cyphar@cyphar.com Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch also fixes build warnings.
tools/testing/selftests/filesystems/fclog.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/tools/testing/selftests/filesystems/fclog.c b/tools/testing/selftests/filesystems/fclog.c index 912a8b755c3b..d7cc3aaa8672 100644 --- a/tools/testing/selftests/filesystems/fclog.c +++ b/tools/testing/selftests/filesystems/fclog.c @@ -6,6 +6,7 @@
#include <assert.h> #include <errno.h> +#include <fcntl.h> #include <sched.h> #include <stdio.h> #include <stdlib.h>
Fix
file_stressor.c:112:9: warning: unused variable 'pid_self'
by dropping the unused variable.
Fixes: aab154a442f9b ("selftests: add file SLAB_TYPESAFE_BY_RCU recycling stressor") Cc: Christian Brauner brauner@kernel.org Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes a build warning.
tools/testing/selftests/filesystems/file_stressor.c | 2 -- 1 file changed, 2 deletions(-)
diff --git a/tools/testing/selftests/filesystems/file_stressor.c b/tools/testing/selftests/filesystems/file_stressor.c index 01dd89f8e52f..4f314270298d 100644 --- a/tools/testing/selftests/filesystems/file_stressor.c +++ b/tools/testing/selftests/filesystems/file_stressor.c @@ -109,8 +109,6 @@ FIXTURE_TEARDOWN(file_stressor) TEST_F_TIMEOUT(file_stressor, slab_typesafe_by_rcu, 900 * 2) { for (int i = 0; i < self->nr_procs; i++) { - pid_t pid_self; - self->pids_openers[i] = fork(); ASSERT_GE(self->pids_openers[i], 0);
Fix
anon_inode_test.c:45:12: warning: call to undeclared function 'execveat'
by adding the missing include file.
Fixes: f8ca403ae77cb ("selftests/filesystems: add exec() test for anonymous inodes") Cc: Christian Brauner brauner@kernel.org Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes a build warning. This patch does not fix: anon_inode_test.c: In function ‘anon_inode_no_exec’: anon_inode_test.c:46:19: warning: argument 3 null where non-null expected because I have no idea how to do avoid that warning.
tools/testing/selftests/filesystems/anon_inode_test.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/tools/testing/selftests/filesystems/anon_inode_test.c b/tools/testing/selftests/filesystems/anon_inode_test.c index 73e0a4d4fb2f..5ddcfd2927f9 100644 --- a/tools/testing/selftests/filesystems/anon_inode_test.c +++ b/tools/testing/selftests/filesystems/anon_inode_test.c @@ -4,6 +4,7 @@
#include <fcntl.h> #include <stdio.h> +#include <unistd.h> #include <sys/stat.h>
#include "../kselftest_harness.h"
Fix:
gcc: error: unrecognized command-line option ‘-Wflex-array-member-not-at-end’
by making the compiler option dependent on its support.
Fixes: 1838731f1072c ("selftest: af_unix: Add -Wall and -Wflex-array-member-not-at-end to CFLAGS.") Cc: Kuniyuki Iwashima kuniyu@google.com Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Just using cc-option is insufficient since it is not defined, and if it is not defined it just disables the option entirely. Include Makefile.compiler and declare the function locally to solve the problem.
tools/testing/selftests/net/af_unix/Makefile | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/net/af_unix/Makefile b/tools/testing/selftests/net/af_unix/Makefile index 3cd677b72072..4c0375e28bbe 100644 --- a/tools/testing/selftests/net/af_unix/Makefile +++ b/tools/testing/selftests/net/af_unix/Makefile @@ -1,4 +1,9 @@ -CFLAGS += $(KHDR_INCLUDES) -Wall -Wflex-array-member-not-at-end +top_srcdir := ../../../../.. +include $(top_srcdir)/scripts/Makefile.compiler + +cc-option = $(call __cc-option, $(CC),,$(1),$(2)) + +CFLAGS += $(KHDR_INCLUDES) -Wall $(call cc-option,-Wflex-array-member-not-at-end)
TEST_GEN_PROGS := \ diag_uid \
test_futex_mpol() is not called, resulting in the following build warning.
futex_numa_mpol.c:134:13: warning: ‘test_futex_mpol’ defined but not used
Disable the function but keep it in case it was supposed to be used.
Fixes: d35ca2f64272 ("selftests/futex: Refactor futex_numa_mpol with kselftest_harness.h") Cc: André Almeida andrealmeid@igalia.com Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes a build warning.
tools/testing/selftests/futex/functional/futex_numa_mpol.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/tools/testing/selftests/futex/functional/futex_numa_mpol.c b/tools/testing/selftests/futex/functional/futex_numa_mpol.c index d037a3f10ee8..8e3d17d66684 100644 --- a/tools/testing/selftests/futex/functional/futex_numa_mpol.c +++ b/tools/testing/selftests/futex/functional/futex_numa_mpol.c @@ -131,10 +131,12 @@ static void test_futex(void *futex_ptr, int err_value) __test_futex(futex_ptr, err_value, FUTEX2_SIZE_U32 | FUTEX_PRIVATE_FLAG | FUTEX2_NUMA); }
+#ifdef NOTUSED static void test_futex_mpol(void *futex_ptr, int err_value) { __test_futex(futex_ptr, err_value, FUTEX2_SIZE_U32 | FUTEX_PRIVATE_FLAG | FUTEX2_NUMA | FUTEX2_MPOL); } +#endif
TEST(futex_numa_mpol) {
The following warning is seen when building netlink-dumps.
netlink-dumps.c: In function ‘dump_extack’: ../kselftest_harness.h:788:35: warning: ‘ret’ may be used uninitialized
Problem is that the loop which initializes 'ret' may exit early without initializing the variable if recv() returns an error. Always initialize 'ret' to solve the problem.
Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes a build warning.
tools/testing/selftests/net/netlink-dumps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/net/netlink-dumps.c b/tools/testing/selftests/net/netlink-dumps.c index 679b6c77ace7..67bf3fc2d66b 100644 --- a/tools/testing/selftests/net/netlink-dumps.c +++ b/tools/testing/selftests/net/netlink-dumps.c @@ -112,7 +112,7 @@ static const struct { TEST(dump_extack) { int netlink_sock; - int i, cnt, ret; + int i, cnt, ret = FOUND_ERR; char buf[8192]; int one = 1; ssize_t n;
Fix:
seccomp_bpf.c: In function ‘UPROBE_setup’: seccomp_bpf.c:5175:74: warning: pointer type mismatch in conditional expression
by type casting the argument to get_uprobe_offset().
Fixes: 9ffc7a635c35a ("selftests/seccomp: validate uprobe syscall passes through seccomp") Cc: Jiri Olsa jolsa@kernel.org Cc: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes a build warning.
tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 874f17763536..2584f4f5c062 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -5172,7 +5172,8 @@ FIXTURE_SETUP(UPROBE) ASSERT_GE(bit, 0); }
- offset = get_uprobe_offset(variant->uretprobe ? probed_uretprobe : probed_uprobe); + offset = get_uprobe_offset(variant->uretprobe ? + (void *)probed_uretprobe : (void *)probed_uprobe); ASSERT_GE(offset, 0);
if (variant->uretprobe)
On Fri, Dec 05, 2025 at 09:10:03AM -0800, Guenter Roeck wrote:
Fix:
seccomp_bpf.c: In function ‘UPROBE_setup’: seccomp_bpf.c:5175:74: warning: pointer type mismatch in conditional expression
by type casting the argument to get_uprobe_offset().
Fixes: 9ffc7a635c35a ("selftests/seccomp: validate uprobe syscall passes through seccomp") Cc: Jiri Olsa jolsa@kernel.org Cc: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Guenter Roeck linux@roeck-us.net
Reviewed-by: Kees Cook kees@kernel.org
Fix
ksft.h: In function ‘ksft_ready’: ksft.h:27:9: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’
ksft.h: In function ‘ksft_wait’: ksft.h:51:9: warning: ignoring return value of ‘read’ declared with attribute ‘warn_unused_result’
by checking the return value of the affected functions and displaying an error message if an error is seen.
Fixes: 2b6d490b82668 ("selftests: drv-net: Factor out ksft C helpers") Cc: Joe Damato jdamato@fastly.com Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes build warnings. Use perror() to display an error message if one of the functions returns an error.
tools/testing/selftests/net/lib/ksft.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/net/lib/ksft.h b/tools/testing/selftests/net/lib/ksft.h index 17dc34a612c6..03912902a6d3 100644 --- a/tools/testing/selftests/net/lib/ksft.h +++ b/tools/testing/selftests/net/lib/ksft.h @@ -24,7 +24,8 @@ static inline void ksft_ready(void) fd = STDOUT_FILENO; }
- write(fd, msg, sizeof(msg)); + if (write(fd, msg, sizeof(msg)) < 0) + perror("write()"); if (fd != STDOUT_FILENO) close(fd); } @@ -48,7 +49,8 @@ static inline void ksft_wait(void) fd = STDIN_FILENO; }
- read(fd, &byte, sizeof(byte)); + if (read(fd, &byte, sizeof(byte)) < 0) + perror("read()"); if (fd != STDIN_FILENO) close(fd); }
Fix
mount-notify_test.c: In function ‘fanotify_rmdir’: mount-notify_test.c:467:17: warning: ignoring return value of ‘chdir’ declared with attribute ‘warn_unused_result’
by checking the return value of chdir() and displaying an error message if an error is reported.
Fixes: e1c24b52adb22 ("selftests: add tests for mount notification") Cc: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes a build warning. Use perror() to display an error message if chdir() returns an error.
.../selftests/filesystems/mount-notify/mount-notify_test.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c index e4b7c2b457ee..5c929275e689 100644 --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c @@ -464,7 +464,8 @@ TEST_F(fanotify, rmdir) ASSERT_GE(ret, 0);
if (ret == 0) { - chdir("/"); + if (chdir("/")) + perror("chdir()"); unshare(CLONE_NEWNS); mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL); umount2("/a", MNT_DETACH);
Fix
mount-notify_test_ns.c: In function ‘fanotify_rmdir’: mount-notify_test_ns.c:494:17: warning: ignoring return value of ‘chdir’ declared with attribute ‘warn_unused_result’
by checking the return value of chdir() and displaying an error message if it returns an error.
Fixes: 781091f3f5945 ("selftests/fs/mount-notify: add a test variant running inside userns") Cc: Amir Goldstein amir73il@gmail.com Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes a build warning. Use perror() to display an error message if chdir() returns an error.
.../selftests/filesystems/mount-notify/mount-notify_test_ns.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c index 9f57ca46e3af..90bec6faf64e 100644 --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c @@ -491,7 +491,8 @@ TEST_F(fanotify, rmdir) ASSERT_GE(ret, 0);
if (ret == 0) { - chdir("/"); + if (chdir("/")) + perror("chdir()"); unshare(CLONE_NEWNS); mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL); umount2("/a", MNT_DETACH);
On Fri, Dec 5, 2025 at 6:12 PM Guenter Roeck linux@roeck-us.net wrote:
Fix
mount-notify_test_ns.c: In function ‘fanotify_rmdir’: mount-notify_test_ns.c:494:17: warning: ignoring return value of ‘chdir’ declared with attribute ‘warn_unused_result’
by checking the return value of chdir() and displaying an error message if it returns an error.
Fixes: 781091f3f5945 ("selftests/fs/mount-notify: add a test variant running inside userns") Cc: Amir Goldstein amir73il@gmail.com Signed-off-by: Guenter Roeck linux@roeck-us.net
v2: Update subject and description to reflect that the patch fixes a build warning. Use perror() to display an error message if chdir() returns an error.
.../selftests/filesystems/mount-notify/mount-notify_test_ns.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c index 9f57ca46e3af..90bec6faf64e 100644 --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c @@ -491,7 +491,8 @@ TEST_F(fanotify, rmdir) ASSERT_GE(ret, 0);
if (ret == 0) {
chdir("/");
if (chdir("/"))perror("chdir()");
ASSERT_EQ(0, chdir("/"));
and there is another one like this in mount-notify_test.c
Thanks, Amir.
On 12/5/25 09:31, Amir Goldstein wrote:
On Fri, Dec 5, 2025 at 6:12 PM Guenter Roeck linux@roeck-us.net wrote:
Fix
mount-notify_test_ns.c: In function ‘fanotify_rmdir’: mount-notify_test_ns.c:494:17: warning: ignoring return value of ‘chdir’ declared with attribute ‘warn_unused_result’
by checking the return value of chdir() and displaying an error message if it returns an error.
Fixes: 781091f3f5945 ("selftests/fs/mount-notify: add a test variant running inside userns") Cc: Amir Goldstein amir73il@gmail.com Signed-off-by: Guenter Roeck linux@roeck-us.net
v2: Update subject and description to reflect that the patch fixes a build warning. Use perror() to display an error message if chdir() returns an error.
.../selftests/filesystems/mount-notify/mount-notify_test_ns.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c index 9f57ca46e3af..90bec6faf64e 100644 --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c @@ -491,7 +491,8 @@ TEST_F(fanotify, rmdir) ASSERT_GE(ret, 0);
if (ret == 0) {
chdir("/");
if (chdir("/"))perror("chdir()");ASSERT_EQ(0, chdir("/"));
and there is another one like this in mount-notify_test.c
Done.
Thanks, Guenter
Fix
tfo.c: In function ‘run_server’: tfo.c:84:9: warning: ignoring return value of ‘read’ declared with attribute ‘warn_unused_result’
by evaluating the return value from read() and displaying an error message if it reports an error.
Fixes: c65b5bb2329e3 ("selftests: net: add passive TFO test binary") Cc: David Wei dw@davidwei.uk Signed-off-by: Guenter Roeck linux@roeck-us.net --- v2: Update subject and description to reflect that the patch fixes a build warning. Use perror() to display an error message if read() returns an error.
tools/testing/selftests/net/tfo.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/net/tfo.c b/tools/testing/selftests/net/tfo.c index eb3cac5e583c..8d82140f0f76 100644 --- a/tools/testing/selftests/net/tfo.c +++ b/tools/testing/selftests/net/tfo.c @@ -81,7 +81,8 @@ static void run_server(void) if (getsockopt(connfd, SOL_SOCKET, SO_INCOMING_NAPI_ID, &opt, &len) < 0) error(1, errno, "getsockopt(SO_INCOMING_NAPI_ID)");
- read(connfd, buf, 64); + if (read(connfd, buf, 64) < 0) + perror("read()"); fprintf(outfile, "%d\n", opt);
fclose(outfile);
linux-kselftest-mirror@lists.linaro.org
-
Amir Goldstein -
Guenter Roeck -
Kees Cook