Commit-ID: f454b478861325f067fd58ba7ee9f1b5c4a9d6a0
Gitweb: http://git.kernel.org/tip/f454b478861325f067fd58ba7ee9f1b5c4a9d6a0
Author: Jan Beulich <[email protected]>
AuthorDate: Wed, 2 Sep 2015 09:45:58 -0600
Committer: Ingo Molnar <[email protected]>
CommitDate: Mon, 14 Sep 2015 12:10:50 +0200
x86/ldt: Fix small LDT allocation for Xen
While the following commit:
37868fe113 ("x86/ldt: Make modify_ldt synchronous")
added a nice comment explaining that Xen needs page-aligned
whole page chunks for guest descriptor tables, it then
nevertheless used kzalloc() on the small size path.
As I'm unaware of guarantees for kmalloc(PAGE_SIZE, ) to return
page-aligned memory blocks, I believe this needs to be switched
back to __get_free_page() (or better get_zeroed_page()).
Signed-off-by: Jan Beulich <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: David Vrabel <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/kernel/ldt.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 2bcc052..6acc9dd 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -58,7 +58,7 @@ static struct ldt_struct *alloc_ldt_struct(int size)
if (alloc_size > PAGE_SIZE)
new_ldt->entries = vzalloc(alloc_size);
else
- new_ldt->entries = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ new_ldt->entries = (void *)get_zeroed_page(GFP_KERNEL);
if (!new_ldt->entries) {
kfree(new_ldt);
@@ -95,7 +95,7 @@ static void free_ldt_struct(struct ldt_struct *ldt)
if (ldt->size * LDT_ENTRY_SIZE > PAGE_SIZE)
vfree(ldt->entries);
else
- kfree(ldt->entries);
+ free_page((unsigned long)ldt->entries);
kfree(ldt);
}
--
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