[LTP] tst_assert: Use 'long long' to fix 32bit compat mode truncation

[linuxtestproject.agent@gmail.com]

Hi Andrea,

On Thu, 24 Sep 2026 13:25:12 +0200, Andrea Cervesato wrote:
> [PATCH 1/3] tst_assert: Use 'long long' to fix 32bit compat mode truncation

--- [PATCH 1/3] ---

> @@ -25,16 +25,17 @@ void tst_assert_int(const char *file, const int lineno, const char *path, int va
>  
>  void tst_assert_ulong(const char *file, const int lineno, const char *path, unsigned long val)
>  {
> -	unsigned long sys_val;
> +	unsigned long long sys_val;
>  
> -	safe_file_scanf(file, lineno, NULL, path, "%lu", &sys_val);
> +	safe_file_scanf(file, lineno, NULL, path, "%llu", &sys_val);
>  
> -	if (val == sys_val) {
> +	if (val == (unsigned long)sys_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",
> +		path, val, (unsigned long)sys_val);
>  }

Casting sys_val to (unsigned long) truncates values exceeding ULONG_MAX on
32-bit systems, causing false passes when (sys_val & 0xFFFFFFFF) == val and
printing a truncated value on failure. Compare values without truncation
using (unsigned long long)val == sys_val, and print sys_val with %llu on
mismatch. Handling of 32-bit compat truncation for /proc/sys/kernel/shmall
should be done in shmctl03.c instead of altering generic library assertions.

--- [PATCH 2/3] ---

> @@ -30,7 +30,14 @@ static void verify_ipcinfo(void)
>  	else
>  		tst_res(TPASS, "shmmin = 1");
>  
> -	TST_ASSERT_ULONG(PATH_KERN_SHMMAX, info.shmmax);
> +	if (tst_is_compat_mode() && info.shmmax == INT_MAX) {
> +		unsigned long long shmmax;
> +		SAFE_FILE_SCANF(PATH_KERN_SHMMAX, "%llu", &shmmax);
> +		TST_EXP_LE_LU(INT_MAX, shmmax);
> +	} else {
> +		TST_ASSERT_ULONG(PATH_KERN_SHMMAX, info.shmmax);
> +	}
> +

Branching on info.shmmax == INT_MAX conditions on the result of the syscall
under test, and TST_EXP_LE_LU(INT_MAX, shmmax) only asserts that the sysctl
file is >= INT_MAX rather than verifying that info.shmmax was clamped.
Read PATH_KERN_SHMMAX into shmmax first, and if in compat mode with
shmmax >= INT_MAX, assert TST_EXP_EQ_LU(info.shmmax, (unsigned long)INT_MAX);
otherwise assert info.shmmax == shmmax.

--- [PATCH 3/3] ---

> +	safe_shmctl(__FILE__, __LINE__, 0, IPC_INFO, ((struct shmid_ds *)&info));

Because shmctl() is the syscall under test, replacing TEST(shmctl(...)) with
safe_shmctl() turns a syscall failure into TBROK instead of TFAIL. In
addition, tests must not call safe_*() functions directly. Keep
TEST(shmctl(...)) or use TST_EXP_PASS(shmctl(0, IPC_INFO, ...)).

> +	TST_EXP_LE_LU(info.shmmin, 1);

TST_EXP_LE_LU() checks info.shmmin <= 1, which incorrectly allows 0 to pass.
The kernel SHMMIN constant is 1 and requires equality. Use
TST_EXP_EQ_LU(info.shmmin, 1).

Verdict - Needs revision

---
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LTP AI Reviewer