Re: [PATCH v2] selftests/ptrace/get_syscall_info: fix for MIPS n32

From: Dmitry V. Levin
Date: Wed Mar 26 2025 - 05:06:55 EST


Could somebody pick up this patch, please?

Nothing has changed since v2, so I have nothing new to add.

v2: https://lore.kernel.org/all/20250115233747.GA28541@xxxxxxxxx/

On Thu, Jan 16, 2025 at 01:37:47AM +0200, Dmitry V. Levin wrote:
> MIPS n32 is one of two ILP32 architectures supported by the kernel
> that have 64-bit syscall arguments (another one is x32).
>
> When this test passed 32-bit arguments to syscall(), they were
> sign-extended in libc, PTRACE_GET_SYSCALL_INFO reported these
> sign-extended 64-bit values, and the test complained about the mismatch.
>
> Fix this by passing arguments of the appropriate type to syscall(),
> which is "unsigned long long" on MIPS n32, and __kernel_ulong_t on other
> architectures.
>
> As a side effect, this also extends the test on all 64-bit architectures
> by choosing constants that don't fit into 32-bit integers.
>
> Signed-off-by: Dmitry V. Levin <ldv@xxxxxxxxx>
> ---
>
> v2: Fixed MIPS #ifdef.
>
> .../selftests/ptrace/get_syscall_info.c | 53 +++++++++++--------
> 1 file changed, 32 insertions(+), 21 deletions(-)
>
> diff --git a/tools/testing/selftests/ptrace/get_syscall_info.c b/tools/testing/selftests/ptrace/get_syscall_info.c
> index 5bcd1c7b5be6..2970f72d66d3 100644
> --- a/tools/testing/selftests/ptrace/get_syscall_info.c
> +++ b/tools/testing/selftests/ptrace/get_syscall_info.c
> @@ -11,8 +11,19 @@
> #include <err.h>
> #include <signal.h>
> #include <asm/unistd.h>
> +#include <linux/types.h>
> #include "linux/ptrace.h"
>
> +#if defined(_MIPS_SIM) && _MIPS_SIM == _MIPS_SIM_NABI32
> +/*
> + * MIPS N32 is the only architecture where __kernel_ulong_t
> + * does not match the bitness of syscall arguments.
> + */
> +typedef unsigned long long kernel_ulong_t;
> +#else
> +typedef __kernel_ulong_t kernel_ulong_t;
> +#endif
> +
> static int
> kill_tracee(pid_t pid)
> {
> @@ -42,37 +53,37 @@ sys_ptrace(int request, pid_t pid, unsigned long addr, unsigned long data)
>
> TEST(get_syscall_info)
> {
> - static const unsigned long args[][7] = {
> + const kernel_ulong_t args[][7] = {
> /* a sequence of architecture-agnostic syscalls */
> {
> __NR_chdir,
> - (unsigned long) "",
> - 0xbad1fed1,
> - 0xbad2fed2,
> - 0xbad3fed3,
> - 0xbad4fed4,
> - 0xbad5fed5
> + (uintptr_t) "",
> + (kernel_ulong_t) 0xdad1bef1bad1fed1ULL,
> + (kernel_ulong_t) 0xdad2bef2bad2fed2ULL,
> + (kernel_ulong_t) 0xdad3bef3bad3fed3ULL,
> + (kernel_ulong_t) 0xdad4bef4bad4fed4ULL,
> + (kernel_ulong_t) 0xdad5bef5bad5fed5ULL
> },
> {
> __NR_gettid,
> - 0xcaf0bea0,
> - 0xcaf1bea1,
> - 0xcaf2bea2,
> - 0xcaf3bea3,
> - 0xcaf4bea4,
> - 0xcaf5bea5
> + (kernel_ulong_t) 0xdad0bef0caf0bea0ULL,
> + (kernel_ulong_t) 0xdad1bef1caf1bea1ULL,
> + (kernel_ulong_t) 0xdad2bef2caf2bea2ULL,
> + (kernel_ulong_t) 0xdad3bef3caf3bea3ULL,
> + (kernel_ulong_t) 0xdad4bef4caf4bea4ULL,
> + (kernel_ulong_t) 0xdad5bef5caf5bea5ULL
> },
> {
> __NR_exit_group,
> 0,
> - 0xfac1c0d1,
> - 0xfac2c0d2,
> - 0xfac3c0d3,
> - 0xfac4c0d4,
> - 0xfac5c0d5
> + (kernel_ulong_t) 0xdad1bef1fac1c0d1ULL,
> + (kernel_ulong_t) 0xdad2bef2fac2c0d2ULL,
> + (kernel_ulong_t) 0xdad3bef3fac3c0d3ULL,
> + (kernel_ulong_t) 0xdad4bef4fac4c0d4ULL,
> + (kernel_ulong_t) 0xdad5bef5fac5c0d5ULL
> }
> };
> - const unsigned long *exp_args;
> + const kernel_ulong_t *exp_args;
>
> pid_t pid = fork();
>
> @@ -154,7 +165,7 @@ TEST(get_syscall_info)
> }
> ASSERT_LT(0, (rc = sys_ptrace(PTRACE_GET_SYSCALL_INFO,
> pid, size,
> - (unsigned long) &info))) {
> + (uintptr_t) &info))) {
> LOG_KILL_TRACEE("PTRACE_GET_SYSCALL_INFO: %m");
> }
> ASSERT_EQ(expected_none_size, rc) {
> @@ -177,7 +188,7 @@ TEST(get_syscall_info)
> case SIGTRAP | 0x80:
> ASSERT_LT(0, (rc = sys_ptrace(PTRACE_GET_SYSCALL_INFO,
> pid, size,
> - (unsigned long) &info))) {
> + (uintptr_t) &info))) {
> LOG_KILL_TRACEE("PTRACE_GET_SYSCALL_INFO: %m");
> }
> switch (ptrace_stop) {
> --
> ldv

--
ldv