[LTP] [PATCH v1] shmctl03: Fix 32-bit compat mode failure by forcing limits

Wei Gao via ltp
2026-04-07T09:26:52Z

On 64-bit kernels, the default shmmax and shmall values often exceed
the range of a 32-bit unsigned long or are clipped differently by the
kernel's compat syscall layer than they appear in /proc.

Link: https://lore.kernel.org/ltp/aJm5SBOaRoe1e0PB@yuki.lan/
Signed-off-by: Wei Gao <wegao@suse.com>
Suggested-by: Cyril Hrubis <chrubis@suse.cz>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
---
include/tst_assert.h | 10 +++++---
lib/tst_assert.c | 25 ++++++++++++++-----
.../kernel/syscalls/ipc/shmctl/shmctl03.c | 12 ++++++---
3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/include/tst_assert.h b/include/tst_assert.h
index dcb62dfea..5b3bd0e12 100644
--- a/include/tst_assert.h
+++ b/include/tst_assert.h
@@ -21,14 +21,18 @@ void tst_assert_int(const char *file, const int lineno,
#define TST_ASSERT_FILE_INT(path, prefix, val) \
tst_assert_file_int(__FILE__, __LINE__, path, prefix, val)

+#define TST_ASSERT_SATURATED_INT 0x01
+#define TST_ASSERT_SATURATED_ULONG 0x02
+#define TST_ASSERT_BITWISE 0x04
+
/*
* Same as tst_assert_int() but for unsigned long.
*/
void tst_assert_ulong(const char *file, const int lineno,
- const char *path, unsigned long val);
+ const char *path, unsigned long val, int flags);

-#define TST_ASSERT_ULONG(path, val) \
- tst_assert_ulong(__FILE__, __LINE__, path, val)
+#define TST_ASSERT_ULONG(path, val, ...) \
+ tst_assert_ulong(__FILE__, __LINE__, path, val, (0, ##__VA_ARGS__))

/*
* Asserts that integer value stored in the prefix field of file pointed by path
diff --git a/lib/tst_assert.c b/lib/tst_assert.c
index b68bd5d39..09d7d8a6f 100644
--- a/lib/tst_assert.c
+++ b/lib/tst_assert.c
@@ -23,18 +23,31 @@ void tst_assert_int(const char *file, const int lineno, const char *path, int va
tst_res_(file, lineno, TFAIL, "%s != %d got %d", path, val, sys_val);
}

-void tst_assert_ulong(const char *file, const int lineno, const char *path, unsigned long val)
+void tst_assert_ulong(const char *file, const int lineno, const char *path,
+ unsigned long val, int flags)
{
- unsigned long sys_val;
-
- safe_file_scanf(file, lineno, NULL, path, "%lu", &sys_val);
+ unsigned long long sys_val_64;
+ unsigned long expected_val;
+
+ safe_file_scanf(file, lineno, NULL, path, "%llu", &sys_val_64);
+
+ if (flags & TST_ASSERT_SATURATED_INT) {
+ expected_val = (sys_val_64 > 2147483647ULL) ? 2147483647UL : (unsigned long)sys_val_64;
+ } else if (flags & TST_ASSERT_SATURATED_ULONG) {
+ expected_val = (sys_val_64 > 4294967295ULL) ? 4294967295UL : (unsigned long)sys_val_64;
+ } else if (flags & TST_ASSERT_BITWISE) {
+ expected_val = (unsigned long)(sys_val_64 & 0xFFFFFFFFULL);
+ } else {
+ expected_val = (unsigned long)sys_val_64;
+ }

- if (val == sys_val) {
+ if (val == expected_val) {
tst_res_(file, lineno, TPASS, "%s = %lu", path, val);
return;
}

- tst_res_(file, lineno, TFAIL, "%s != %lu got %lu", path, val, sys_val);
+ tst_res_(file, lineno, TFAIL, "%s != %lu got %lu (raw: %llu)",
+ path, val, expected_val, sys_val_64);
}

void tst_assert_file_int(const char *file, const int lineno, const char *path, const char *prefix, int val)
diff --git a/testcases/kernel/syscalls/ipc/shmctl/shmctl03.c b/testcases/kernel/syscalls/ipc/shmctl/shmctl03.c
index a1f53e7c1..6d073789c 100644
--- a/testcases/kernel/syscalls/ipc/shmctl/shmctl03.c
+++ b/testcases/kernel/syscalls/ipc/shmctl/shmctl03.c
@@ -30,9 +30,15 @@ static void verify_ipcinfo(void)
else
tst_res(TPASS, "shmmin = 1");

- TST_ASSERT_ULONG("/proc/sys/kernel/shmmax", info.shmmax);
- TST_ASSERT_ULONG("/proc/sys/kernel/shmmni", info.shmmni);
- TST_ASSERT_ULONG("/proc/sys/kernel/shmall", info.shmall);
+ if (tst_is_compat_mode()) {
+ TST_ASSERT_ULONG("/proc/sys/kernel/shmmax", info.shmmax, TST_ASSERT_SATURATED_INT);
+ TST_ASSERT_ULONG("/proc/sys/kernel/shmmni", info.shmmni, TST_ASSERT_BITWISE);
+ TST_ASSERT_ULONG("/proc/sys/kernel/shmall", info.shmall, TST_ASSERT_BITWISE);
+ } else {
+ TST_ASSERT_ULONG("/proc/sys/kernel/shmmax", info.shmmax);
+ TST_ASSERT_ULONG("/proc/sys/kernel/shmmni", info.shmmni);
+ TST_ASSERT_ULONG("/proc/sys/kernel/shmall", info.shmall);
+ }
}

static struct tst_test test = {
--
2.52.0