Re: [PATCH v1 11/14] futex: Implement FUTEX2_NUMA
From: Peter Zijlstra <peterz@infradead.org>
Date: 2023-07-21 12:17:09
Also in:
linux-arch, linux-mm, lkml
On Fri, Jul 21, 2023 at 12:22:48PM +0200, Peter Zijlstra wrote:
quoted hunk ↗ jump to hunk
@@ -217,32 +259,55 @@ static u64 get_inode_sequence_number(str * * lock_page() might sleep, the caller should not hold a spinlock. */ -int get_futex_key(u32 __user *uaddr, unsigned int flags, union futex_key *key, +int get_futex_key(void __user *uaddr, unsigned int flags, union futex_key *key, enum futex_access rw) { unsigned long address = (unsigned long)uaddr; struct mm_struct *mm = current->mm; struct page *page, *tail; struct address_space *mapping; + int node, err, size, ro = 0; bool fshared; fshared = flags & FLAGS_SHARED; + size = futex_size(flags); /* * The futex address must be "naturally" aligned. */ key->both.offset = address % PAGE_SIZE; + if (unlikely((address % size) != 0)) return -EINVAL;
This enforces u32 alignment for:
struct futex_numa_32 {
u32 val;
u32 node;
};
Or do we want to enfore u64 alignment for that?
address -= key->both.offset; + if (flags & FLAGS_NUMA) + size *= 2; + + if (unlikely(!access_ok(uaddr, size))) return -EFAULT;