diff options
| author | Gerald Schaefer <gerald.schaefer@linux.ibm.com> | 2022-08-17 15:26:03 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-09-05 10:27:44 +0200 |
| commit | 09602177d80c5bcf2556f0830ce8c8362973e6c3 (patch) | |
| tree | ed5b0993ae6d6b65999854e42842413a77d2f16a | |
| parent | c9c5501e815132530d741ec9fdd22657f91656bc (diff) | |
s390/mm: do not trigger write fault when vma does not allow VM_WRITE
commit 41ac42f137080bc230b5882e3c88c392ab7f2d32 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 92f842eac7ee3 ("[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: 92f842eac7ee3 ("[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: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/s390/mm/fault.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 7b0bb475c166..9770381776a6 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -432,7 +432,9 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; if (user_mode(regs)) flags |= FAULT_FLAG_USER; - if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) + if ((trans_exc_code & store_indication) == 0x400) + access = VM_WRITE; + if (access == VM_WRITE) flags |= FAULT_FLAG_WRITE; down_read(&mm->mmap_sem); |