On Wed, May 6, 2020 at 1:22 PM Brian Geffon <bgeffon@xxxxxxxxxx> wrote: > > A user is not required to set a new address when using > MREMAP_DONTUNMAP as it can be used without MREMAP_FIXED. > When doing so the remap event will use new_addr which may not > have been set and we didn't propagate it back other then > in the return value of remap_to. > > Because ret is always the new address it's probably more > correct to use it rather than new_addr on the remap_event_complete > call, and it resolves this bug. > > Signed-off-by: Brian Geffon <bgeffon@xxxxxxxxxx> > --- > mm/mremap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/mremap.c b/mm/mremap.c > index c881abeba0bf..6aa6ea605068 100644 > --- a/mm/mremap.c > +++ b/mm/mremap.c > @@ -794,7 +794,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, > if (locked && new_len > old_len) > mm_populate(new_addr + old_len, new_len - old_len); > userfaultfd_unmap_complete(mm, &uf_unmap_early); > - mremap_userfaultfd_complete(&uf, addr, new_addr, old_len); > + mremap_userfaultfd_complete(&uf, addr, ret, old_len); Not super familiar with this code, but thought I'd ask, does ret need to be checked for -ENOMEM before calling mremap_userfaultfd_complete? Sorry if I missed something. Thanks, - Joel > userfaultfd_unmap_complete(mm, &uf_unmap); > return ret; > } > -- > 2.26.2.526.g744177e7f7-goog >
