linux-kernel - [PATCH] adjust gfp mask passed on nested vmalloc() invocation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <4AC9E38E0200007800017F57@vpn.id2.novell.com>
Date:	Mon, 05 Oct 2009 11:16:14 +0100
From:	"Jan Beulich" <JBeulich@...ell.com>
To:	"Andrew Morton" <akpm@...ux-foundation.org>
Cc:	<linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] adjust gfp mask passed on nested vmalloc() invocation

- fix a latent bug resulting from blindly or-ing in __GFP_ZERO, since
  the combination of this and __GFP_HIGHMEM (possibly passed into the
  function) is forbidden in interrupt context
- avoid wasting more precious resources (DMA or DMA32 pools), when
  being called through vmalloc_32{,_user}()
- explicitly allow using high memory here even if the outer allocation
  request doesn't allow it, unless is collides with __GFP_ZERO

Signed-off-by: Jan Beulich <jbeulich@...ell.com>

---
 mm/vmalloc.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- linux-2.6.32-rc3/mm/vmalloc.c	2009-10-05 11:59:56.000000000 +0200
+++ 2.6.32-rc3-vmalloc-nested-gfp/mm/vmalloc.c	2009-10-05 08:40:36.000000000 +0200
@@ -1410,6 +1410,7 @@ static void *__vmalloc_area_node(struct 
 {
 	struct page **pages;
 	unsigned int nr_pages, array_size, i;
+	gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
 
 	nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
 	array_size = (nr_pages * sizeof(struct page *));
@@ -1417,13 +1418,16 @@ static void *__vmalloc_area_node(struct 
 	area->nr_pages = nr_pages;
 	/* Please note that the recursion is strictly bounded. */
 	if (array_size > PAGE_SIZE) {
-		pages = __vmalloc_node(array_size, gfp_mask | __GFP_ZERO,
+#ifdef CONFIG_HIGHMEM
+		/* See the comment in prep_zero_page(). */
+		if (!in_interrupt())
+			nested_gfp |= __GFP_HIGHMEM;
+#endif
+		pages = __vmalloc_node(array_size, nested_gfp,
 				PAGE_KERNEL, node, caller);
 		area->flags |= VM_VPAGES;
 	} else {
-		pages = kmalloc_node(array_size,
-				(gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO,
-				node);
+		pages = kmalloc_node(array_size, nested_gfp, node);
 	}
 	area->pages = pages;
 	area->caller = caller;



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/