Okay, let's try to figure out the category for this bug report. The user is talking about QEMU's linux-user mode and binfmt_misc. The problem is that when using qemu with the open-binary flag, if file descriptor 0 is closed, QEMU opens the executable as fd 0, which is supposed to be stdin. This leads to programs thinking that stdin is their own executable, which causes test failures in coreutils. The issue seems to be in how QEMU handles the AT_EXECFD auxiliary value. The code in main.c checks if AT_EXECFD is 0 and then opens the executable, but maybe it's not correctly distinguishing between a valid 0 value and the case where AT_EXECFD isn't present. The user mentions that qemu_getauxval doesn't differentiate between not found and a value of 0. The solution might involve checking errno after calling getauxval to determine if AT_EXECFD actually exists. Now, looking at the categories: instruction, syscall, or runtime. The problem is about how QEMU processes the auxiliary vector during execution, which is part of the runtime handling of the program's execution environment. It's not about a specific syscall (though syscalls are involved), but more about the logic during runtime when setting up the process. So the category is likely 'runtime'. runtime