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authorDmitriy Monakhov <dmonakhov@openvz.org>2006-10-19 23:29:08 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-20 10:26:43 -0700
commitc4ec7b0de4bc18ccb4380de638550984d9a65c25 (patch)
treea6a3ac91b4865f436f26c387a28eae08c310f1a0 /mm/memory.c
parentca926e80dcfd18adaf7c4304935da4cc8ded8364 (diff)
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[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/memory.c')
-rw-r--r--mm/memory.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index b5a4aadd961..156861fcac4 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;
}