Okay, I need to figure out whether this getresuid() issue in QEMU is a user-mode or system-mode problem. The report mentions that when running on qemu-user-sparc64, the UID values are getting their 16-bit halves swapped, leading to incorrect results. First, let me recall what user-mode and system-mode emulation involve. User-mode QEMU (like qemu-user) handles executing the guest application by translating its instructions into the host's architecture. It deals with system calls by intercepting them and emulating the expected behavior using the host's kernel. On the other hand, system-mode QEMU runs a full virtual machine, including a virtualized kernel, devices, etc., providing a complete environment. In this case, the issue occurs when calling getresuid() in the guest, which is a system call. The problem seems to be that the UID values are being byte-swapped incorrectly. Since the test uses qemu-sparc64-static, which I think is part of user-mode emulation, the system calls are being handled by QEMU's user-mode code. So, if the bug happens in QEMU when emulating getresuid(), it's likely that the problem lies within how QEMU handles this particular system call. The fact that it doesn't occur outside of QEMU points to QEMU itself as the source of the issue rather than the kernel or glibc on the host. Therefore, this is a user-mode related bug because it involves how QEMU translates and handles the system calls in the user-space environment. user