diff options
| author | Dmitriy Monakhov <dmonakhov@openvz.org> | 2006-10-19 23:29:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-10-20 10:26:43 -0700 |
| commit | c4ec7b0de4bc18ccb4380de638550984d9a65c25 (patch) | |
| tree | a6a3ac91b4865f436f26c387a28eae08c310f1a0 /mm | |
| parent | ca926e80dcfd18adaf7c4304935da4cc8ded8364 (diff) | |
| download | lwn-c4ec7b0de4bc18ccb4380de638550984d9a65c25.tar.gz lwn-c4ec7b0de4bc18ccb4380de638550984d9a65c25.zip | |
[PATCH] mm: D-cache aliasing issue in cow_user_page
--=-=-=
from mm/memory.c:
1434 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
1435 {
1436 /*
1437 * If the source page was a PFN mapping, we don't have
1438 * a "struct page" for it. We do a best-effort copy by
1439 * just copying from the original user address. If that
1440 * fails, we just zero-fill it. Live with it.
1441 */
1442 if (unlikely(!src)) {
1443 void *kaddr = kmap_atomic(dst, KM_USER0);
1444 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1445
1446 /*
1447 * This really shouldn't fail, because the page is there
1448 * in the page tables. But it might just be unreadable,
1449 * in which case we just give up and fill the result with
1450 * zeroes.
1451 */
1452 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
1453 memset(kaddr, 0, PAGE_SIZE);
1454 kunmap_atomic(kaddr, KM_USER0);
#### D-cache have to be flushed here.
#### It seems it is just forgotten.
1455 return;
1456
1457 }
1458 copy_user_highpage(dst, src, va);
#### Ok here. flush_dcache_page() called from this func if arch need it
1459 }
Following is the patch fix this issue:
Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c index b5a4aadd961a..156861fcac43 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1452,6 +1452,7 @@ static inline void cow_user_page(struct page *dst, struct page *src, unsigned lo if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) memset(kaddr, 0, PAGE_SIZE); kunmap_atomic(kaddr, KM_USER0); + flush_dcache_page(dst); return; } |