[PATCH 2/2] selftests/user_events: Fix pointer casts for 32-bit builds
From: Danish Khateeb
Date: Mon Sep 28 2026 - 13:21:24 EST
The tests cast pointers directly to __u64. On 32-bit builds GCC
sign-extends such casts, so addresses above 2 GiB, like the stack of a
32-bit task on a 64-bit kernel, become 0xffffffffxxxxxxxx and every
registration fails.
Cast through uintptr_t so the tests also work when built for 32-bit and
cover the compat ioctl path.
Assisted-by: LLM
Signed-off-by: Danish Khateeb <danishkhateeb03@xxxxxxxxx>
---
Notes:
Built with and without -m32. With 1/2 applied, the 32-bit tests pass on
x86_64; the 64-bit binaries are unchanged in behaviour and still pass.
The -Wpointer-to-int-cast warnings left in a 32-bit build come from
kselftest_harness.h, not from these tests.
.../testing/selftests/user_events/abi_test.c | 10 +++---
.../testing/selftests/user_events/dyn_test.c | 6 ++--
.../selftests/user_events/ftrace_test.c | 32 +++++++++----------
.../testing/selftests/user_events/perf_test.c | 10 +++---
4 files changed, 29 insertions(+), 29 deletions(-)
diff --git a/tools/testing/selftests/user_events/abi_test.c b/tools/testing/selftests/user_events/abi_test.c
index b71813eaf5c0..21e1e3cca197 100644
--- a/tools/testing/selftests/user_events/abi_test.c
+++ b/tools/testing/selftests/user_events/abi_test.c
@@ -179,10 +179,10 @@ static int reg_enable_multi(void *enable, int size, int bit, int flags,
}
reg.size = sizeof(reg);
- reg.name_args = (__u64)full_args;
+ reg.name_args = (__u64)(uintptr_t)full_args;
reg.flags = USER_EVENT_REG_MULTI_FORMAT | flags;
reg.enable_bit = bit;
- reg.enable_addr = (__u64)enable;
+ reg.enable_addr = (__u64)(uintptr_t)enable;
reg.enable_size = size;
ret = ioctl(fd, DIAG_IOCSREG, ®);
@@ -202,10 +202,10 @@ static int reg_enable_flags(void *enable, int size, int bit, int flags)
return -1;
reg.size = sizeof(reg);
- reg.name_args = (__u64)"__abi_event";
+ reg.name_args = (__u64)(uintptr_t)"__abi_event";
reg.flags = flags;
reg.enable_bit = bit;
- reg.enable_addr = (__u64)enable;
+ reg.enable_addr = (__u64)(uintptr_t)enable;
reg.enable_size = size;
ret = ioctl(fd, DIAG_IOCSREG, ®);
@@ -231,7 +231,7 @@ static int reg_disable(void *enable, int bit)
reg.size = sizeof(reg);
reg.disable_bit = bit;
- reg.disable_addr = (__u64)enable;
+ reg.disable_addr = (__u64)(uintptr_t)enable;
ret = ioctl(fd, DIAG_IOCSUNREG, ®);
diff --git a/tools/testing/selftests/user_events/dyn_test.c b/tools/testing/selftests/user_events/dyn_test.c
index 78e3c33f4015..32f159544d0b 100644
--- a/tools/testing/selftests/user_events/dyn_test.c
+++ b/tools/testing/selftests/user_events/dyn_test.c
@@ -58,9 +58,9 @@ static int reg_event(int fd, int *check, int bit, const char *value)
struct user_reg reg = {0};
reg.size = sizeof(reg);
- reg.name_args = (__u64)value;
+ reg.name_args = (__u64)(uintptr_t)value;
reg.enable_bit = bit;
- reg.enable_addr = (__u64)check;
+ reg.enable_addr = (__u64)(uintptr_t)check;
reg.enable_size = sizeof(*check);
if (ioctl(fd, DIAG_IOCSREG, ®) == -1)
@@ -75,7 +75,7 @@ static int unreg_event(int fd, int *check, int bit)
unreg.size = sizeof(unreg);
unreg.disable_bit = bit;
- unreg.disable_addr = (__u64)check;
+ unreg.disable_addr = (__u64)(uintptr_t)check;
return ioctl(fd, DIAG_IOCSUNREG, &unreg);
}
diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/testing/selftests/user_events/ftrace_test.c
index decce06b9ba8..b9c75202f0bd 100644
--- a/tools/testing/selftests/user_events/ftrace_test.c
+++ b/tools/testing/selftests/user_events/ftrace_test.c
@@ -127,7 +127,7 @@ static int clear(int *check)
unreg.size = sizeof(unreg);
unreg.disable_bit = 31;
- unreg.disable_addr = (__u64)check;
+ unreg.disable_addr = (__u64)(uintptr_t)check;
fd = open(data_file, O_RDWR);
@@ -174,9 +174,9 @@ static int check_print_fmt(const char *event, const char *expected, int *check)
return fd;
reg.size = sizeof(reg);
- reg.name_args = (__u64)event;
+ reg.name_args = (__u64)(uintptr_t)event;
reg.enable_bit = 31;
- reg.enable_addr = (__u64)check;
+ reg.enable_addr = (__u64)(uintptr_t)check;
reg.enable_size = sizeof(*check);
/* Register should work */
@@ -239,14 +239,14 @@ TEST_F(user, register_events) {
struct user_unreg unreg = {0};
reg.size = sizeof(reg);
- reg.name_args = (__u64)"__test_event u32 field1; u32 field2";
+ reg.name_args = (__u64)(uintptr_t)"__test_event u32 field1; u32 field2";
reg.enable_bit = 31;
- reg.enable_addr = (__u64)&self->check;
+ reg.enable_addr = (__u64)(uintptr_t)&self->check;
reg.enable_size = sizeof(self->check);
unreg.size = sizeof(unreg);
unreg.disable_bit = 31;
- unreg.disable_addr = (__u64)&self->check;
+ unreg.disable_addr = (__u64)(uintptr_t)&self->check;
/* Register should work */
ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, ®));
@@ -263,13 +263,13 @@ TEST_F(user, register_events) {
/* Register without separator spacing should still match */
reg.enable_bit = 29;
- reg.name_args = (__u64)"__test_event u32 field1;u32 field2";
+ reg.name_args = (__u64)(uintptr_t)"__test_event u32 field1;u32 field2";
ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, ®));
ASSERT_EQ(0, reg.write_index);
/* Multiple registers to same name but different args should fail */
reg.enable_bit = 29;
- reg.name_args = (__u64)"__test_event u32 field1;";
+ reg.name_args = (__u64)(uintptr_t)"__test_event u32 field1;";
ASSERT_EQ(-1, ioctl(self->data_fd, DIAG_IOCSREG, ®));
ASSERT_EQ(EADDRINUSE, errno);
@@ -310,9 +310,9 @@ TEST_F(user, write_events) {
int before = 0, after = 0;
reg.size = sizeof(reg);
- reg.name_args = (__u64)"__test_event u32 field1; u32 field2";
+ reg.name_args = (__u64)(uintptr_t)"__test_event u32 field1; u32 field2";
reg.enable_bit = 31;
- reg.enable_addr = (__u64)&self->check;
+ reg.enable_addr = (__u64)(uintptr_t)&self->check;
reg.enable_size = sizeof(self->check);
field1 = 1;
@@ -367,9 +367,9 @@ TEST_F(user, write_empty_events) {
int before = 0, after = 0;
reg.size = sizeof(reg);
- reg.name_args = (__u64)"__test_event";
+ reg.name_args = (__u64)(uintptr_t)"__test_event";
reg.enable_bit = 31;
- reg.enable_addr = (__u64)&self->check;
+ reg.enable_addr = (__u64)(uintptr_t)&self->check;
reg.enable_size = sizeof(self->check);
io[0].iov_base = ®.write_index;
@@ -401,9 +401,9 @@ TEST_F(user, write_fault) {
void *anon;
reg.size = sizeof(reg);
- reg.name_args = (__u64)"__test_event u64 anon";
+ reg.name_args = (__u64)(uintptr_t)"__test_event u64 anon";
reg.enable_bit = 31;
- reg.enable_addr = (__u64)&self->check;
+ reg.enable_addr = (__u64)(uintptr_t)&self->check;
reg.enable_size = sizeof(self->check);
anon = mmap(NULL, l, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
@@ -439,9 +439,9 @@ TEST_F(user, write_validator) {
int before = 0, after = 0;
reg.size = sizeof(reg);
- reg.name_args = (__u64)"__test_event __rel_loc char[] data";
+ reg.name_args = (__u64)(uintptr_t)"__test_event __rel_loc char[] data";
reg.enable_bit = 31;
- reg.enable_addr = (__u64)&self->check;
+ reg.enable_addr = (__u64)(uintptr_t)&self->check;
reg.enable_size = sizeof(self->check);
/* Register should work */
diff --git a/tools/testing/selftests/user_events/perf_test.c b/tools/testing/selftests/user_events/perf_test.c
index 5727cb5b914c..b444d114b2f0 100644
--- a/tools/testing/selftests/user_events/perf_test.c
+++ b/tools/testing/selftests/user_events/perf_test.c
@@ -89,7 +89,7 @@ static int clear(int *check)
unreg.size = sizeof(unreg);
unreg.disable_bit = 31;
- unreg.disable_addr = (__u64)check;
+ unreg.disable_addr = (__u64)(uintptr_t)check;
int fd = open(data_file, O_RDWR);
@@ -160,9 +160,9 @@ TEST_F(user, perf_write) {
__u32 *val;
reg.size = sizeof(reg);
- reg.name_args = (__u64)"__test_event u32 field1; u32 field2";
+ reg.name_args = (__u64)(uintptr_t)"__test_event u32 field1; u32 field2";
reg.enable_bit = 31;
- reg.enable_addr = (__u64)&self->check;
+ reg.enable_addr = (__u64)(uintptr_t)&self->check;
reg.enable_size = sizeof(self->check);
/* Register should work */
@@ -224,9 +224,9 @@ TEST_F(user, perf_empty_events) {
__u32 *val;
reg.size = sizeof(reg);
- reg.name_args = (__u64)"__test_event";
+ reg.name_args = (__u64)(uintptr_t)"__test_event";
reg.enable_bit = 31;
- reg.enable_addr = (__u64)&self->check;
+ reg.enable_addr = (__u64)(uintptr_t)&self->check;
reg.enable_size = sizeof(self->check);
/* Register should work */
--
2.55.0