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authorJan Kara <jack@suse.cz>2019-03-28 20:43:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-29 10:01:37 -0700
commitcae85cb8add35f678cf487139d05e083ce2f570a (patch)
treef347aa8b0f66edfe01b7ffceb6ea26d4daec5bc2 /mm/memory.c
parentkasan: fix variable 'tag' set but not used warning (diff)
downloadlinux-dev-cae85cb8add35f678cf487139d05e083ce2f570a.tar.xz
linux-dev-cae85cb8add35f678cf487139d05e083ce2f570a.zip
mm/memory.c: fix modifying of page protection by insert_pfn()
Aneesh has reported that PPC triggers the following warning when excercising DAX code: IP set_pte_at+0x3c/0x190 LR insert_pfn+0x208/0x280 Call Trace: insert_pfn+0x68/0x280 dax_iomap_pte_fault.isra.7+0x734/0xa40 __xfs_filemap_fault+0x280/0x2d0 do_wp_page+0x48c/0xa40 __handle_mm_fault+0x8d0/0x1fd0 handle_mm_fault+0x140/0x250 __do_page_fault+0x300/0xd60 handle_page_fault+0x18 Now that is WARN_ON in set_pte_at which is VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep)); The problem is that on some architectures set_pte_at() cannot cope with a situation where there is already some (different) valid entry present. Use ptep_set_access_flags() instead to modify the pfn which is built to deal with modifying existing PTE. Link: http://lkml.kernel.org/r/20190311084537.16029-1-jack@suse.cz Fixes: b2770da64254 "mm: add vm_insert_mixed_mkwrite()" Signed-off-by: Jan Kara <jack@suse.cz> Reported-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Cc: Chandan Rajendra <chandan@linux.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r--mm/memory.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 47fe250307c7..ab650c21bccd 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1549,10 +1549,12 @@ static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr,
WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte)));
goto out_unlock;
}
- entry = *pte;
- goto out_mkwrite;
- } else
- goto out_unlock;
+ entry = pte_mkyoung(*pte);
+ entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ if (ptep_set_access_flags(vma, addr, pte, entry, 1))
+ update_mmu_cache(vma, addr, pte);
+ }
+ goto out_unlock;
}
/* Ok, finally just insert the thing.. */
@@ -1561,7 +1563,6 @@ static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr,
else
entry = pte_mkspecial(pfn_t_pte(pfn, prot));
-out_mkwrite:
if (mkwrite) {
entry = pte_mkyoung(entry);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);