Commit-ID: 103f6112f253017d7062cd74d17f4a514ed4485c Gitweb: http://git.kernel.org/tip/103f6112f253017d7062cd74d17f4a514ed4485c Author: Jan Beulich <[email protected]> AuthorDate: Thu, 21 Apr 2016 00:27:04 -0600 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 22 Apr 2016 10:05:00 +0200
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 <[email protected]> Signed-off-by: Jan Beulich <[email protected]> Cc: Andrew Morton <[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: Juergen Gross <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Luis R. Rodriguez <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Toshi Kani <[email protected]> Cc: [email protected] Cc: xen-devel <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/include/asm/hugetlb.h | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h index f8a29d2..e6a8613 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,
