Messages in this thread Patch in this message | | | Date | Tue, 01 Sep 2015 04:48:19 -0600 | From | "Jan Beulich" <> | Subject | [PATCH] x86: fix small LDT allocation for Xen |
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While 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().
Signed-off-by: Jan Beulich <jbeulich@suse.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- arch/x86/kernel/ldt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 4.2/arch/x86/kernel/ldt.c +++ 4.2-x86-LDT-alloc/arch/x86/kernel/ldt.c @@ -58,7 +58,7 @@ static struct ldt_struct *alloc_ldt_stru 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_free_page(GFP_KERNEL|__GFP_ZERO); if (!new_ldt->entries) { kfree(new_ldt);
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