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authorVineet Gupta <vgupta@synopsys.com>2016-07-28 11:35:50 -0700
committerSasha Levin <alexander.levin@verizon.com>2016-08-19 23:07:58 -0400
commit93c0b008e79f11430ce07b6271b37671051d4298 (patch)
tree2efef22620a3947036a630c390399fe5ca8f9347
parentae9c7f35df23c4d187e0e9c3f8e23f3ca7587e40 (diff)
ARC: mm: don't loose PTE_SPECIAL in pte_modify()
[ Upstream commit 3925a16ae980c79d1a8fd182d7f9487da1edd4dc ] LTP madvise05 was generating mm splat | [ARCLinux]# /sd/ltp/testcases/bin/madvise05 | BUG: Bad page map in process madvise05 pte:80e08211 pmd:9f7d4000 | page:9fdcfc90 count:1 mapcount:-1 mapping: (null) index:0x0 flags: 0x404(referenced|reserved) | page dumped because: bad pte | addr:200b8000 vm_flags:00000070 anon_vma: (null) mapping: (null) index:1005c | file: (null) fault: (null) mmap: (null) readpage: (null) | CPU: 2 PID: 6707 Comm: madvise05 And for newer kernels, the system was rendered unusable afterwards. The problem was mprotect->pte_modify() clearing PTE_SPECIAL (which is set to identify the special zero page wired to the pte). When pte was finally unmapped, special casing for zero page was not done, and instead it was treated as a "normal" page, tripping on the map counts etc. This fixes ARC STAR 9001053308 Cc: <stable@vger.kernel.org> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
-rw-r--r--arch/arc/include/asm/pgtable.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 9615fe1701c6..09c549826c5f 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -96,7 +96,7 @@
#define ___DEF (_PAGE_PRESENT | _PAGE_DEF_CACHEABLE)
/* Set of bits not changed in pte_modify */
-#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_MODIFIED)
+#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_MODIFIED | _PAGE_SPECIAL)
/* More Abbrevaited helpers */
#define PAGE_U_NONE __pgprot(___DEF)