On Thu, Feb 16, 2023 at 02:57:38PM +0100, Oleg Nesterov wrote: > On 02/14, Gregory Price wrote: > > > > +struct compat_ptrace_sud_config { > > + compat_ulong_t mode; > > + compat_uptr_t selector; > > + compat_ulong_t offset; > > + compat_ulong_t len; > > +}; > > ... > > > +int syscall_user_dispatch_get_config(struct task_struct *task, unsigned long size, > > + void __user *data) > > +{ > > + struct syscall_user_dispatch *sd = &task->syscall_dispatch; > > +#ifdef CONFIG_COMPAT > > + if (unlikely(in_compat_syscall())) { > > + struct compat_ptrace_sud_config cfg32; > > + > > + if (size != sizeof(struct compat_ptrace_sud_config)) > > + return -EINVAL; > > + > > Horror ;) why? > > See my reply to v9, just make > > struct ptrace_sud_config { > __u8 mode; > __u64 selector; > __u64 offset; > __u64 len; > }; > > Oleg. > It was unclear to me what the prior note was asking an I followed the pattern of other compat code in ptrace. For some reason i got it in my head that u64 would compile down to u32 in compatibility mode and i went full-stupid. will back out this compat code here and fixup the struct.