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authorGerald Schaefer <gerald.schaefer@linux.ibm.com>2022-08-17 15:26:03 +0200
committerVasily Gorbik <gor@linux.ibm.com>2022-08-25 15:12:32 +0200
commit41ac42f137080bc230b5882e3c88c392ab7f2d32 (patch)
treed454e16d9988785b5de5426e2b29ad3c9e8637a3 /arch/s390
parents390: fix double free of GS and RI CBs on fork() failure (diff)
downloadlinux-41ac42f137080bc230b5882e3c88c392ab7f2d32.tar.xz
linux-41ac42f137080bc230b5882e3c88c392ab7f2d32.zip
s390/mm: do not trigger write fault when vma does not allow VM_WRITE
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>
Diffstat (limited to 'arch/s390')
-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 13449941516c..09b6e756d521 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -379,7 +379,9 @@ 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);