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  1. 19 9月, 2012 9 次提交
  3. 05 9月, 2012 7 次提交
  5. 28 8月, 2012 1 次提交
  7. 23 8月, 2012 3 次提交
  9. 22 8月, 2012 5 次提交
    • T
      KVM: MMU: Fix mmu_shrink() so that it can free mmu pages as intended · 35f2d16b
      由 Takuya Yoshikawa 提交于 
      Although the possible race described in

  commit 85b70591
  KVM: MMU: fix shrinking page from the empty mmu

was correct, the real cause of that issue was a more trivial bug of
mmu_shrink() introduced by

  commit 19526396
  KVM: MMU: do not iterate over all VMs in mmu_shrink()

Here is the bug:

	if (kvm->arch.n_used_mmu_pages > 0) {
		if (!nr_to_scan--)
			break;
		continue;
	}

We skip VMs whose n_used_mmu_pages is not zero and try to shrink others:
in other words we try to shrink empty ones by mistake.

This patch reverses the logic so that mmu_shrink() can free pages from
the first VM whose n_used_mmu_pages is not zero.  Note that we also add
comments explaining the role of nr_to_scan which is not practically
important now, hoping this will be improved in the future.
Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>
      35f2d16b
    • A
      x86/alternatives: Fix p6 nops on non-modular kernels · cb09cad4
      由 Avi Kivity 提交于 
      Probably a leftover from the early days of self-patching, p6nops
are marked __initconst_or_module, which causes them to be
discarded in a non-modular kernel.  If something later triggers
patching, it will overwrite kernel code with garbage.
Reported-by: NTomas Racek <tracek@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: qemu-devel@nongnu.org
Cc: Anthony Liguori <anthony@codemonkey.ws>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Alan Cox <alan@linux.intel.com>
Link: http://lkml.kernel.org/r/5034AE84.90708@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      cb09cad4
    • L
      x86/fixup_irq: Use cpu_online_mask instead of cpu_all_mask · 2530cd4f
      由 Liu, Chuansheng 提交于 
      When one CPU is going down and this CPU is the last one in irq
affinity, current code is setting cpu_all_mask as the new
affinity for that irq.

But for some systems (such as in Medfield Android mobile) the
firmware sends the interrupt to each CPU in the irq affinity
mask, averaged, and cpu_all_mask includes all potential CPUs,
i.e. offline ones as well.

So replace cpu_all_mask with cpu_online_mask.
Signed-off-by: Nliu chuansheng <chuansheng.liu@intel.com>
Acked-by: NYanmin Zhang <yanmin_zhang@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/27240C0AC20F114CBF8149A2696CBE4A137286@SHSMSX101.ccr.corp.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      2530cd4f
    • R
      x86/spinlocks: Fix comment in spinlock.h · 83be4ffa
      由 Richard Weinberger 提交于 
      This comment is no longer true.  We support up to 2^16 CPUs
because __ticket_t is an u16 if NR_CPUS is larger than 256.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      83be4ffa
    • M
      mm: hugetlbfs: correctly populate shared pmd · eb48c071
      由 Michal Hocko 提交于 
      Each page mapped in a process's address space must be correctly
accounted for in _mapcount.  Normally the rules for this are
straightforward but hugetlbfs page table sharing is different.  The page
table pages at the PMD level are reference counted while the mapcount
remains the same.

If this accounting is wrong, it causes bugs like this one reported by
Larry Woodman:

  kernel BUG at mm/filemap.c:135!
  invalid opcode: 0000 [#1] SMP
  CPU 22
  Modules linked in: bridge stp llc sunrpc binfmt_misc dcdbas microcode pcspkr acpi_pad acpi]
  Pid: 18001, comm: mpitest Tainted: G        W    3.3.0+ #4 Dell Inc. PowerEdge R620/07NDJ2
  RIP: 0010:[<ffffffff8112cfed>]  [<ffffffff8112cfed>] __delete_from_page_cache+0x15d/0x170
  Process mpitest (pid: 18001, threadinfo ffff880428972000, task ffff880428b5cc20)
  Call Trace:
    delete_from_page_cache+0x40/0x80
    truncate_hugepages+0x115/0x1f0
    hugetlbfs_evict_inode+0x18/0x30
    evict+0x9f/0x1b0
    iput_final+0xe3/0x1e0
    iput+0x3e/0x50
    d_kill+0xf8/0x110
    dput+0xe2/0x1b0
    __fput+0x162/0x240

During fork(), copy_hugetlb_page_range() detects if huge_pte_alloc()
shared page tables with the check dst_pte == src_pte.  The logic is if
the PMD page is the same, they must be shared.  This assumes that the
sharing is between the parent and child.  However, if the sharing is
with a different process entirely then this check fails as in this
diagram:

  parent
    |
    ------------>pmd
                 src_pte----------> data page
                                        ^
  other--------->pmd--------------------|
                  ^
  child-----------|
                 dst_pte

For this situation to occur, it must be possible for Parent and Other to
have faulted and failed to share page tables with each other.  This is
possible due to the following style of race.

  PROC A                                          PROC B
  copy_hugetlb_page_range                         copy_hugetlb_page_range
    src_pte == huge_pte_offset                      src_pte == huge_pte_offset
    !src_pte so no sharing                          !src_pte so no sharing

  (time passes)

  hugetlb_fault                                   hugetlb_fault
    huge_pte_alloc                                  huge_pte_alloc
      huge_pmd_share                                 huge_pmd_share
        LOCK(i_mmap_mutex)
        find nothing, no sharing
        UNLOCK(i_mmap_mutex)
                                                      LOCK(i_mmap_mutex)
                                                      find nothing, no sharing
                                                      UNLOCK(i_mmap_mutex)
      pmd_alloc                                       pmd_alloc
      LOCK(instantiation_mutex)
      fault
      UNLOCK(instantiation_mutex)
                                                  LOCK(instantiation_mutex)
                                                  fault
                                                  UNLOCK(instantiation_mutex)

These two processes are not poing to the same data page but are not
sharing page tables because the opportunity was missed.  When either
process later forks, the src_pte == dst pte is potentially insufficient.
As the check falls through, the wrong PTE information is copied in
(harmless but wrong) and the mapcount is bumped for a page mapped by a
shared page table leading to the BUG_ON.

This patch addresses the issue by moving pmd_alloc into huge_pmd_share
which guarantees that the shared pud is populated in the same critical
section as pmd.  This also means that huge_pte_offset test in
huge_pmd_share is serialized correctly now which in turn means that the
success of the sharing will be higher as the racing tasks see the pud
and pmd populated together.

Race identified and changelog written mostly by Mel Gorman.

{akpm@linux-foundation.org: attempt to make the huge_pmd_share() comment comprehensible, clean up coding style]
Reported-by: NLarry Woodman <lwoodman@redhat.com>
Tested-by: NLarry Woodman <lwoodman@redhat.com>
Reviewed-by: NMel Gorman <mgorman@suse.de>
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NRik van Riel <riel@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Ken Chen <kenchen@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      eb48c071
  11. 19 8月, 2012 1 次提交
    • M
      x32: Use compat shims for {g,s}etsockopt · 515c7af8
      由 Mike Frysinger 提交于 
      Some of the arguments to {g,s}etsockopt are passed in userland pointers.
If we try to use the 64bit entry point, we end up sometimes failing.

For example, dhcpcd doesn't run in x32:
	# dhcpcd eth0
	dhcpcd[1979]: version 5.5.6 starting
	dhcpcd[1979]: eth0: broadcasting for a lease
	dhcpcd[1979]: eth0: open_socket: Invalid argument
	dhcpcd[1979]: eth0: send_raw_packet: Bad file descriptor

The code in particular is getting back EINVAL when doing:
	struct sock_fprog pf;
	setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &pf, sizeof(pf));

Diving into the kernel code, we can see:
include/linux/filter.h:
	struct sock_fprog {
		unsigned short len;
		struct sock_filter __user *filter;
	};

net/core/sock.c:
	case SO_ATTACH_FILTER:
		ret = -EINVAL;
		if (optlen == sizeof(struct sock_fprog)) {
			struct sock_fprog fprog;

			ret = -EFAULT;
			if (copy_from_user(&fprog, optval, sizeof(fprog)))
				break;

			ret = sk_attach_filter(&fprog, sk);
		}
		break;

arch/x86/syscalls/syscall_64.tbl:
	54 common setsockopt sys_setsockopt
	55 common getsockopt sys_getsockopt

So for x64, sizeof(sock_fprog) is 16 bytes.  For x86/x32, it's 8 bytes.
This comes down to the pointer being 32bit for x32, which means we need
to do structure size translation.  But since x32 comes in directly to
sys_setsockopt, it doesn't get translated like x86.

After changing the syscall table and rebuilding glibc with the new kernel
headers, dhcp runs fine in an x32 userland.

Oddly, it seems like Linus noted the same thing during the initial port,
but I guess that was missed/lost along the way:
	https://lkml.org/lkml/2011/8/26/452

[ hpa: tagging for -stable since this is an ABI fix. ]

Bugzilla: https://bugs.gentoo.org/423649Reported-by: NMads <mads@ab3.no>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Link: http://lkml.kernel.org/r/1345320697-15713-1-git-send-email-vapier@gentoo.org
Cc: H. J. Lu <hjl.tools@gmail.com>
Cc: <stable@vger.kernel.org> v3.4..v3.5
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      515c7af8
  13. 17 8月, 2012 2 次提交
  15. 15 8月, 2012 2 次提交
  17. 14 8月, 2012 4 次提交
  19. 11 8月, 2012 1 次提交
  21. 09 8月, 2012 1 次提交
  23. 05 8月, 2012 1 次提交
  25. 03 8月, 2012 1 次提交
  27. 02 8月, 2012 2 次提交
    • K
      xen/p2m: Reserve 8MB of _brk space for P2M leafs when populating back. · 5bc6f988
      由 Konrad Rzeszutek Wilk 提交于 
      When we release pages back during bootup:

Freeing  9d-100 pfn range: 99 pages freed
Freeing  9cf36-9d0d2 pfn range: 412 pages freed
Freeing  9f6bd-9f6bf pfn range: 2 pages freed
Freeing  9f714-9f7bf pfn range: 171 pages freed
Freeing  9f7e0-9f7ff pfn range: 31 pages freed
Freeing  9f800-100000 pfn range: 395264 pages freed
Released 395979 pages of unused memory

We then try to populate those pages back. In the P2M tree however
the space for those leafs must be reserved - as such we use extend_brk.
We reserve 8MB of _brk space, which means we can fit over
1048576 PFNs - which is more than we should ever need.

Without this, on certain compilation of the kernel we would hit:

(XEN) domain_crash_sync called from entry.S
(XEN) CPU:    0
(XEN) RIP:    e033:[<ffffffff818aad3b>]
(XEN) RFLAGS: 0000000000000206   EM: 1   CONTEXT: pv guest
(XEN) rax: ffffffff81a7c000   rbx: 000000000000003d   rcx: 0000000000001000
(XEN) rdx: ffffffff81a7b000   rsi: 0000000000001000   rdi: 0000000000001000
(XEN) rbp: ffffffff81801cd8   rsp: ffffffff81801c98   r8:  0000000000100000
(XEN) r9:  ffffffff81a7a000   r10: 0000000000000001   r11: 0000000000000003
(XEN) r12: 0000000000000004   r13: 0000000000000004   r14: 000000000000003d
(XEN) r15: 00000000000001e8   cr0: 000000008005003b   cr4: 00000000000006f0
(XEN) cr3: 0000000125803000   cr2: 0000000000000000
(XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: e02b   cs: e033
(XEN) Guest stack trace from rsp=ffffffff81801c98:

.. which is extend_brk hitting a BUG_ON.

Interestingly enough, most of the time we are not going to hit this
b/c the _brk space is quite large (v3.5):
 ffffffff81a25000 B __brk_base
 ffffffff81e43000 B __brk_limit
= ~4MB.

vs earlier kernels (with this back-ported), the space is smaller:
 ffffffff81a25000 B __brk_base
 ffffffff81a7b000 B __brk_limit
= 344 kBytes.

where we would certainly hit this and hit extend_brk.

Note that git commit c3d93f88
(xen: populate correct number of pages when across mem boundary (v2))
exposed this bug).

[v1: Made it 8MB of _brk space instead of 4MB per Jan's suggestion]

CC: stable@vger.kernel.org #only for 3.5
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      5bc6f988
    • A
      KVM: VMX: Fix ds/es corruption on i386 with preemption · aa67f609
      由 Avi Kivity 提交于 
      Commit b2da15ac ("KVM: VMX: Optimize %ds, %es reload") broke i386
in the following scenario:

  vcpu_load
  ...
  vmx_save_host_state
  vmx_vcpu_run
  (ds.rpl, es.rpl cleared by hardware)

  interrupt
    push ds, es  # pushes bad ds, es
    schedule
      vmx_vcpu_put
        vmx_load_host_state
          reload ds, es (with __USER_DS)
    pop ds, es  # of other thread's stack
    iret
  # other thread runs
  interrupt
    push ds, es
    schedule  # back in vcpu thread
    pop ds, es  # now with rpl=0
    iret
  ...
  vcpu_put
  resume_userspace
  iret  # clears ds, es due to mismatched rpl

(instead of resume_userspace, we might return with SYSEXIT and then
take an exception; when the exception IRETs we end up with cleared
ds, es)

Fix by avoiding the optimization on i386 and reloading ds, es on the
lightweight exit path.
Reported-by: NChris Clayron <chris2553@googlemail.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
      aa67f609