ARM: 7479/1: mm: avoid NULL dereference when flushing gate_vma with VIVT caches

The vivt_flush_cache_{range,page} functions check that the mm_struct
of the VMA being flushed has been active on the current CPU before
performing the cache maintenance.

The gate_vma has a NULL mm_struct pointer and, as such, will cause a
kernel fault if we try to flush it with the above operations. This
happens during ELF core dumps, which include the gate_vma as it may be
useful for debugging purposes.

This patch adds checks to the VIVT cache flushing functions so that VMAs
with a NULL mm_struct are flushed unconditionally (the vectors page may
be dirty if we use it to store the current TLS pointer).

Cc: <[email protected]> # 3.4+
Reported-by: Gilles Chanteperdrix <[email protected]>
Tested-by: Uros Bizjak <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Russell King <[email protected]>

0 files changed, 0 insertions, 0 deletions