path: root/arch
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authorJan Beulich <>2016-04-21 00:27:04 -0600
committerIngo Molnar <>2016-04-22 10:05:00 +0200
commit103f6112f253017d7062cd74d17f4a514ed4485c (patch)
tree1e393c429bb4fe6e30b9f65a3200dca882e7a0d4 /arch
parent78b0634d2851d30ec5d289aefbae23b141de67f0 (diff)
x86/mm/xen: Suppress hugetlbfs in PV guests
Huge pages are not normally available to PV guests. Not suppressing hugetlbfs use results in an endless loop of page faults when user mode code tries to access a hugetlbfs mapped area (since the hypervisor denies such PTEs to be created, but error indications can't be propagated out of xen_set_pte_at(), just like for various of its siblings), and - once killed in an oops like this: kernel BUG at .../fs/hugetlbfs/inode.c:428! invalid opcode: 0000 [#1] SMP ... RIP: e030:[<ffffffff811c333b>] [<ffffffff811c333b>] remove_inode_hugepages+0x25b/0x320 ... Call Trace: [<ffffffff811c3415>] hugetlbfs_evict_inode+0x15/0x40 [<ffffffff81167b3d>] evict+0xbd/0x1b0 [<ffffffff8116514a>] __dentry_kill+0x19a/0x1f0 [<ffffffff81165b0e>] dput+0x1fe/0x220 [<ffffffff81150535>] __fput+0x155/0x200 [<ffffffff81079fc0>] task_work_run+0x60/0xa0 [<ffffffff81063510>] do_exit+0x160/0x400 [<ffffffff810637eb>] do_group_exit+0x3b/0xa0 [<ffffffff8106e8bd>] get_signal+0x1ed/0x470 [<ffffffff8100f854>] do_signal+0x14/0x110 [<ffffffff810030e9>] prepare_exit_to_usermode+0xe9/0xf0 [<ffffffff814178a5>] retint_user+0x8/0x13 This is CVE-2016-3961 / XSA-174. Reported-by: Vitaly Kuznetsov <> Signed-off-by: Jan Beulich <> Cc: Andrew Morton <> Cc: Andy Lutomirski <> Cc: Boris Ostrovsky <> Cc: Borislav Petkov <> Cc: Brian Gerst <> Cc: David Vrabel <> Cc: Denys Vlasenko <> Cc: H. Peter Anvin <> Cc: Juergen Gross <> Cc: Linus Torvalds <> Cc: Luis R. Rodriguez <> Cc: Peter Zijlstra <> Cc: Thomas Gleixner <> Cc: Toshi Kani <> Cc: Cc: xen-devel <> Link: Signed-off-by: Ingo Molnar <>
Diffstat (limited to 'arch')
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h
index f8a29d2c97b0..e6a8613fbfb0 100644
--- a/arch/x86/include/asm/hugetlb.h
+++ b/arch/x86/include/asm/hugetlb.h
@@ -4,6 +4,7 @@
#include <asm/page.h>
#include <asm-generic/hugetlb.h>
+#define hugepages_supported() cpu_has_pse
static inline int is_hugepage_only_range(struct mm_struct *mm,
unsigned long addr,