MAP_GROWSDOWN flag is not supported by PCuABI specification. Hence, reject such requests with -EOPNOTSUPP error.
Signed-off-by: Amit Daniel Kachhap amitdaniel.kachhap@arm.com --- mm/mmap.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/mm/mmap.c b/mm/mmap.c index cb069b76d761..67a208465d0d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1458,6 +1458,17 @@ user_uintptr_t ksys_mmap_pgoff(user_uintptr_t user_ptr, unsigned long len, return PTR_ERR(file); }
+ /* + * Introduce checks for PCuABI: + * - MAP_GROWSDOWN flag has no fixed bounds and hence is not supported + * in the PCuABI reservation model. + */ + if (reserv_is_supported(current->mm)) { + if (flags & MAP_GROWSDOWN) { + retval = -EOPNOTSUPP; + goto out_fput; + } + } retval = check_pcuabi_params(user_ptr, len, flags, false, true, false); if (retval) goto out_fput;