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authorGerald Schaefer <gerald.schaefer@linux.ibm.com>2022-08-17 15:26:03 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-08-31 17:16:48 +0200
commit9227599cd987704c6dfc94b9929fc4a21ed1c4ab (patch)
treeff1fda24883a3b1be631188ec18d08ee3fd50aa8
parentddcb0696136b9af1c8d489fd4763e12f52864b95 (diff)
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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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/s390/mm/fault.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 212632d57db9..c930dff312df 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -397,7 +397,9 @@ 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 || is_write)
+ if (is_write)
+ access = VM_WRITE;
+ if (access == VM_WRITE)
flags |= FAULT_FLAG_WRITE;
mmap_read_lock(mm);