On Thu, Nov 24, 2022, at 13:48, Jason A. Donenfeld wrote: > On Thu, Nov 24, 2022 at 01:24:42PM +0100, Jason A. Donenfeld wrote: > Looks like set_mempolicy, get_mempoliy, and migrate_pages pass an > unsigned long pointer and I don't see any compat stuff around it: > > SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long > __user *, nmask, > unsigned long, maxnode) > > SYSCALL_DEFINE5(get_mempolicy, int __user *, policy, > unsigned long __user *, nmask, unsigned long, maxnode, > unsigned long, addr, unsigned long, flags) > > SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode, > const unsigned long __user *, old_nodes, > const unsigned long __user *, new_nodes) Compat handling for these is done all the way down in the pointer access: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/mempolicy.c#n1368 This works here because it's a special bitmap but is not the best approach if you just have a pointer to a single value. Arnd
