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authorAndrew Morton <akpm@osdl.org>2006-03-22 00:08:42 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-22 07:54:02 -0800
commit6626c5d53bc45c59798628677ba5606f02e371f3 (patch)
tree7be40e7709b1887648a649fd6b5c036638c4608b
parent17cf44064ae744f081309108fa67f0e942b10167 (diff)
[PATCH] mm: prep_zero_page() in irq is a bug
prep_zero_page() uses KM_USER0 and hence may not be used from IRQ context, at least for highmem pages. Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <christoph@lameter.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--mm/page_alloc.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bdff8589963..ed91684cb1f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -217,6 +217,11 @@ static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
int i;
BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM);
+ /*
+ * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
+ * and __GFP_HIGHMEM from hard or soft interrupt context.
+ */
+ BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
for (i = 0; i < (1 << order); i++)
clear_highpage(page + i);
}