On 2/8/24 01:26, Alexei Starovoitov wrote:
Also I believe I addressed all issues with missing mutex and wrap around,
and pushed to:
https://git.kernel.org/pub/scm/linux/kernel/git/ast/bpf.git/commit/?h=arena&id=e1cb522fee661e7346e8be567eade9cf607eaf11
Please take a look.
LGTM, thanks.
minor things:
+static void arena_vm_close(struct vm_area_struct *vma)
+{
+ struct vma_list *vml;
+
+ vml = vma->vm_private_data;
+ list_del(&vml->head);
+ vma->vm_private_data = NULL;
+ kfree(vml);
+}
i think this also needs protected by the arena mutex. otherwise two
VMAs that close at the same time can corrupt the arena vma_list. or a
VMA that closes while you're zapping.
remember_vma() already has the mutex held, since it's called from mmap.
+static long arena_alloc_pages(struct bpf_arena *arena, long uaddr, long page_cnt, int node_id)
+{
+ long page_cnt_max = (arena->user_vm_end - arena->user_vm_start) >> PAGE_SHIFT;
this function and arena_free_pages() are both using user_vm_start/end
before grabbing the mutex. so need to grab the mutex very early.
alternatively, you could make it so that the user must set the
user_vm_start via map_extra, so you don't have to worry about these
changing after the arena is created.
thanks,
barret
