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| author | Gerald Schaefer <gerald.schaefer@linux.ibm.com> | 2022-08-17 16:26:03 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-09-05 11:28:55 +0300 |
| commit | b9feeb610099d01805f24b9f5a72e4abb2fe18d6 (patch) | |
| tree | ad35a439b62846759a7b5c2cfdc8dcf6d3ed4742 | |
| parent | 0dea6b3e22c67b37aeb1fca8fa5398fd38270f57 (diff) | |
| download | linux-b9feeb610099d01805f24b9f5a72e4abb2fe18d6.tar.xz | |
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 ed517fad0d03..1866374356c8 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -429,7 +429,9 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) flags = FAULT_FLAG_DEFAULT; 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; mmap_read_lock(mm); |