mm/gup: do not return 0 from pin_user_pages_fast() for bad args

These routines are not intended to return zero, the callers cannot do
anything sane with a 0 return.  They should return an error which means
future calls to GUP will not succeed, or they should return some non-zero
number of pinned pages which means GUP should be called again.

If start + nr_pages overflows it should return -EOVERFLOW to signal the
arguments are invalid.

Syzkaller keeps tripping on this when fuzzing GUP arguments.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Jason Gunthorpe <[email protected]>
Reported-by: [email protected]
Closes: https://lore.kernel.org/all/[email protected]
Reviewed-by: John Hubbard <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions