103f6112f2
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 <vkuznets@redhat.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juergen Gross <JGross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hp.com> Cc: stable@vger.kernel.org Cc: xen-devel <xen-devel@lists.xenproject.org> Link: http://lkml.kernel.org/r/57188ED802000078000E431C@prv-mh.provo.novell.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|---|---|---|
| .. | ||
| asm | ||
| uapi/asm | ||