s390/mm: do not trigger write fault when vma does not allow VM_WRITE
commit 41ac42f1 upstream. For non-protection pXd_none() page faults in do_dat_exception(), we call do_exception() with access == (VM_READ | VM_WRITE | VM_EXEC). In do_exception(), vma->vm_flags is checked against that before calling handle_mm_fault(). Since commit 92f842ea ("[S390] store indication fault optimization"), we call handle_mm_fault() with FAULT_FLAG_WRITE, when recognizing that it was a write access. However, the vma flags check is still only checking against (VM_READ | VM_WRITE | VM_EXEC), and therefore also calling handle_mm_fault() with FAULT_FLAG_WRITE in cases where the vma does not allow VM_WRITE. Fix this by changing access check in do_exception() to VM_WRITE only, when recognizing write access. Link: https://lkml.kernel.org/r/20220811103435.188481-3-david@redhat.com Fixes: 92f842ea ("[S390] store indication fault optimization") Cc: <stable@vger.kernel.org> Reported-by:David Hildenbrand <david@redhat.com> Reviewed-by:
Heiko Carstens <hca@linux.ibm.com> Signed-off-by:
Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by:
Vasily Gorbik <gor@linux.ibm.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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c035edae
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