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  1. 06 5月, 2016 13 次提交
    • J
      lib/stackdepot: avoid to return 0 handle · 7c31190b
      由 Joonsoo Kim 提交于 
      Recently, we allow to save the stacktrace whose hashed value is 0.  It
causes the problem that stackdepot could return 0 even if in success.
User of stackdepot cannot distinguish whether it is success or not so we
need to solve this problem.  In this patch, 1 bit are added to handle
and make valid handle none 0 by setting this bit.  After that, valid
handle will not be 0 and 0 handle will represent failure correctly.

Fixes: 33334e25 ("lib/stackdepot.c: allow the stack trace hash to be zero")
Link: http://lkml.kernel.org/r/1462252403-1106-1-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7c31190b
    • V
      mm: fix kcompactd hang during memory offlining · 172400c6
      由 Vlastimil Babka 提交于 
      Assume memory47 is the last online block left in node1.  This will hang:

  # echo offline > /sys/devices/system/node/node1/memory47/state

After a couple of minutes, the following pops up in dmesg:

  INFO: task bash:957 blocked for more than 120 seconds.
         Not tainted 4.6.0-rc6+ #6
  "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  bash            D ffff8800b7adbaf8     0   957    951 0x00000000
  Call Trace:
    schedule+0x35/0x80
    schedule_timeout+0x1ac/0x270
    wait_for_completion+0xe1/0x120
    kthread_stop+0x4f/0x110
    kcompactd_stop+0x26/0x40
    __offline_pages.constprop.28+0x7e6/0x840
    offline_pages+0x11/0x20
    memory_block_action+0x73/0x1d0
    memory_subsys_offline+0x47/0x60
    device_offline+0x86/0xb0
    store_mem_state+0xda/0xf0
    dev_attr_store+0x18/0x30
    sysfs_kf_write+0x37/0x40
    kernfs_fop_write+0x11d/0x170
    __vfs_write+0x37/0x120
    vfs_write+0xa9/0x1a0
    SyS_write+0x55/0xc0
    entry_SYSCALL_64_fastpath+0x1a/0xa4

kcompactd is waiting for kcompactd_max_order > 0 when it's woken up to
actually exit.  Check kthread_should_stop() to break out of the wait.

Fixes: 698b1b30 ("mm, compaction: introduce kcompactd").
Reported-by: NReza Arbab <arbab@linux.vnet.ibm.com>
Tested-by: NReza Arbab <arbab@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      172400c6
    • P
      modpost: fix module autoloading for OF devices with generic compatible property · acbef7b7
      由 Philipp Zabel 提交于 
      Since the wildcard at the end of OF module aliases is gone, autoloading
of modules that don't match a device's last (most generic) compatible
value fails.

For example the CODA960 VPU on i.MX6Q has the SoC specific compatible
"fsl,imx6q-vpu" and the generic compatible "cnm,coda960".  Since the
driver currently only works with knowledge about the SoC specific
integration, it doesn't list "cnm,cod960" in the module device table.

This results in the device compatible
"of:NvpuT<NULL>Cfsl,imx6q-vpuCcnm,coda960" not matching the module alias
"of:N*T*Cfsl,imx6q-vpu" anymore, whereas before commit 2f632369
("modpost: don't add a trailing wildcard for OF module aliases") it
matched the module alias "of:N*T*Cfsl,imx6q-vpu*".

This patch adds two module aliases for each compatible, one without the
wildcard and one with "C*" appended.

  $ modinfo coda | grep imx6q
  alias:          of:N*T*Cfsl,imx6q-vpuC*
  alias:          of:N*T*Cfsl,imx6q-vpu

Fixes: 2f632369 ("modpost: don't add a trailing wildcard for OF module aliases")
Link: http://lkml.kernel.org/r/1462203339-15340-1-git-send-email-p.zabel@pengutronix.deSigned-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Cc: Javier Martinez Canillas <javier@osg.samsung.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>	[4.5+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      acbef7b7
    • M
      proc: prevent accessing /proc/<PID>/environ until it's ready · 8148a73c
      由 Mathias Krause 提交于 
      If /proc/<PID>/environ gets read before the envp[] array is fully set up
in create_{aout,elf,elf_fdpic,flat}_tables(), we might end up trying to
read more bytes than are actually written, as env_start will already be
set but env_end will still be zero, making the range calculation
underflow, allowing to read beyond the end of what has been written.

Fix this as it is done for /proc/<PID>/cmdline by testing env_end for
zero.  It is, apparently, intentionally set last in create_*_tables().

This bug was found by the PaX size_overflow plugin that detected the
arithmetic underflow of 'this_len = env_end - (env_start + src)' when
env_end is still zero.

The expected consequence is that userland trying to access
/proc/<PID>/environ of a not yet fully set up process may get
inconsistent data as we're in the middle of copying in the environment
variables.

Fixes: https://forums.grsecurity.net/viewtopic.php?f=3&t=4363
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=116461Signed-off-by: NMathias Krause <minipli@googlemail.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: Pax Team <pageexec@freemail.hu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Jarod Wilson <jarod@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8148a73c
    • D
      mm/zswap: provide unique zpool name · 32a4e169
      由 Dan Streetman 提交于 
      Instead of using "zswap" as the name for all zpools created, add an
atomic counter and use "zswap%x" with the counter number for each zpool
created, to provide a unique name for each new zpool.

As zsmalloc, one of the zpool implementations, requires/expects a unique
name for each pool created, zswap should provide a unique name.  The
zsmalloc pool creation does not fail if a new pool with a conflicting
name is created, unless CONFIG_ZSMALLOC_STAT is enabled; in that case,
zsmalloc pool creation fails with -ENOMEM.  Then zswap will be unable to
change its compressor parameter if its zpool is zsmalloc; it also will
be unable to change its zpool parameter back to zsmalloc, if it has any
existing old zpool using zsmalloc with page(s) in it.  Attempts to
change the parameters will result in failure to create the zpool.  This
changes zswap to provide a unique name for each zpool creation.

Fixes: f1c54846 ("zswap: dynamic pool creation")
Signed-off-by: NDan Streetman <ddstreet@ieee.org>
Reported-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Dan Streetman <dan.streetman@canonical.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      32a4e169
    • A
      mm: thp: kvm: fix memory corruption in KVM with THP enabled · 127393fb
      由 Andrea Arcangeli 提交于 
      After the THP refcounting change, obtaining a compound pages from
get_user_pages() no longer allows us to assume the entire compound page
is immediately mappable from a secondary MMU.

A secondary MMU doesn't want to call get_user_pages() more than once for
each compound page, in order to know if it can map the whole compound
page.  So a secondary MMU needs to know from a single get_user_pages()
invocation when it can map immediately the entire compound page to avoid
a flood of unnecessary secondary MMU faults and spurious
atomic_inc()/atomic_dec() (pages don't have to be pinned by MMU notifier
users).

Ideally instead of the page->_mapcount < 1 check, get_user_pages()
should return the granularity of the "page" mapping in the "mm" passed
to get_user_pages().  However it's non trivial change to pass the "pmd"
status belonging to the "mm" walked by get_user_pages up the stack (up
to the caller of get_user_pages).  So the fix just checks if there is
not a single pte mapping on the page returned by get_user_pages, and in
turn if the caller can assume that the whole compound page is mapped in
the current "mm" (in a pmd_trans_huge()).  In such case the entire
compound page is safe to map into the secondary MMU without additional
get_user_pages() calls on the surrounding tail/head pages.  In addition
of being faster, not having to run other get_user_pages() calls also
reduces the memory footprint of the secondary MMU fault in case the pmd
split happened as result of memory pressure.

Without this fix after a MADV_DONTNEED (like invoked by QEMU during
postcopy live migration or balloning) or after generic swapping (with a
failure in split_huge_page() that would only result in pmd splitting and
not a physical page split), KVM would map the whole compound page into
the shadow pagetables, despite regular faults or userfaults (like
UFFDIO_COPY) may map regular pages into the primary MMU as result of the
pte faults, leading to the guest mode and userland mode going out of
sync and not working on the same memory at all times.

Any other secondary MMU notifier manager (KVM is just one of the many
MMU notifier users) will need the same information if it doesn't want to
run a flood of get_user_pages_fast and it can support multiple
granularity in the secondary MMU mappings, so I think it is justified to
be exposed not just to KVM.

The other option would be to move transparent_hugepage_adjust to
mm/huge_memory.c but that currently has all kind of KVM data structures
in it, so it's definitely not a cut-and-paste work, so I couldn't do a
fix as cleaner as this one for 4.6.
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: "Li, Liang Z" <liang.z.li@intel.com>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      127393fb
    • E
      MAINTAINERS: fix Rajendra Nayak's address · ff2de822
      由 Eric Engestrom 提交于 
      Signed-off-by: NEric Engestrom <eric.engestrom@imgtec.com>
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Cc: Afzal Mohammed <afzal.mohd.ma@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ff2de822
    • H
      mm, cma: prevent nr_isolated_* counters from going negative · 14af4a5e
      由 Hugh Dickins 提交于 
      /proc/sys/vm/stat_refresh warns nr_isolated_anon and nr_isolated_file go
increasingly negative under compaction: which would add delay when
should be none, or no delay when should delay.  The bug in compaction
was due to a recent mmotm patch, but much older instance of the bug was
also noticed in isolate_migratepages_range() which is used for CMA and
gigantic hugepage allocations.

The bug is caused by putback_movable_pages() in an error path
decrementing the isolated counters without them being previously
incremented by acct_isolated().  Fix isolate_migratepages_range() by
removing the error-path putback, thus reaching acct_isolated() with
migratepages still isolated, and leaving putback to caller like most
other places do.

Fixes: edc2ca61 ("mm, compaction: move pageblock checks up from isolate_migratepages_range()")
[vbabka@suse.cz: expanded the changelog]
Signed-off-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      14af4a5e
    • J
      mm: update min_free_kbytes from khugepaged after core initialization · bc22af74
      由 Jason Baron 提交于 
      Khugepaged attempts to raise min_free_kbytes if its set too low.
However, on boot khugepaged sets min_free_kbytes first from
subsys_initcall(), and then the mm 'core' over-rides min_free_kbytes
after from init_per_zone_wmark_min(), via a module_init() call.

Khugepaged used to use a late_initcall() to set min_free_kbytes (such
that it occurred after the core initialization), however this was
removed when the initialization of min_free_kbytes was integrated into
the starting of the khugepaged thread.

The fix here is simply to invoke the core initialization using a
core_initcall() instead of module_init(), such that the previous
initialization ordering is restored.  I didn't restore the
late_initcall() since start_stop_khugepaged() already sets
min_free_kbytes via set_recommended_min_free_kbytes().

This was noticed when we had a number of page allocation failures when
moving a workload to a kernel with this new initialization ordering.  On
an 8GB system this restores min_free_kbytes back to 67584 from 11365
when CONFIG_TRANSPARENT_HUGEPAGE=y is set and either
CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS=y or
CONFIG_TRANSPARENT_HUGEPAGE_MADVISE=y.

Fixes: 79553da2 ("thp: cleanup khugepaged startup")
Signed-off-by: NJason Baron <jbaron@akamai.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      bc22af74
    • H
      huge pagecache: mmap_sem is unlocked when truncation splits pmd · 68428398
      由 Hugh Dickins 提交于 
      zap_pmd_range()'s CONFIG_DEBUG_VM !rwsem_is_locked(&mmap_sem) BUG() will
be invalid with huge pagecache, in whatever way it is implemented:
truncation of a hugely-mapped file to an unhugely-aligned size would
easily hit it.

(Although anon THP could in principle apply khugepaged to private file
mappings, which are not excluded by the MADV_HUGEPAGE restrictions, in
practice there's a vm_ops check which excludes them, so it never hits
this BUG() - there's no interface to "truncate" an anonymous mapping.)

We could complicate the test, to check i_mmap_rwsem also when there's a
vm_file; but my inclination was to make zap_pmd_range() more readable by
simply deleting this check.  A search has shown no report of the issue
in the years since commit e0897d75 ("mm, thp: print useful
information when mmap_sem is unlocked in zap_pmd_range") expanded it
from VM_BUG_ON() - though I cannot point to what commit I would say then
fixed the issue.

But there are a couple of other patches now floating around, neither yet
in the tree: let's agree to retain the check as a VM_BUG_ON_VMA(), as
Matthew Wilcox has done; but subject to a vma_is_anonymous() check, as
Kirill Shutemov has done.  And let's get this in, without waiting for
any particular huge pagecache implementation to reach the tree.

Matthew said "We can reproduce this BUG() in the current Linus tree with
DAX PMDs".
Signed-off-by: NHugh Dickins <hughd@google.com>
Tested-by: NMatthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Yang Shi <yang.shi@linaro.org>
Cc: Ning Qu <quning@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      68428398
    • A
      rapidio/mport_cdev: fix uapi type definitions · 4e1016da
      由 Alexandre Bounine 提交于 
      Fix problems in uapi definitions reported by Gabriel Laskar: (see
https://lkml.org/lkml/2016/4/5/205 for details)

 - move public header file rio_mport_cdev.h to include/uapi/linux directory
 - change types in data structures passed as IOCTL parameters
 - improve parameter checking in some IOCTL service routines
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Reported-by: NGabriel Laskar <gabriel@lse.epita.fr>
Tested-by: NBarry Wood <barry.wood@idt.com>
Cc: Gabriel Laskar <gabriel@lse.epita.fr>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
Cc: Barry Wood <barry.wood@idt.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4e1016da
    • J
      mm: memcontrol: let v2 cgroups follow changes in system swappiness · 4550c4e1
      由 Johannes Weiner 提交于 
      Cgroup2 currently doesn't have a per-cgroup swappiness setting.  We
might want to add one later - that's a different discussion - but until
we do, the cgroups should always follow the system setting.  Otherwise
it will be unchangeably set to whatever the ancestor inherited from the
system setting at the time of cgroup creation.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Cc: <stable@vger.kernel.org>	[4.5]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4550c4e1
    • Y
      mm: thp: correct split_huge_pages file permission · 145bdaa1
      由 Yang Shi 提交于 
      split_huge_pages doesn't support get method at all, so the read
permission sounds confusing, change the permission to write only.

And, add "\n" to the output of set method to make it more readable.
Signed-off-by: NYang Shi <yang.shi@linaro.org>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      145bdaa1
  3. 05 5月, 2016 6 次提交
    • L
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace · c5e0666c
      由 Linus Torvalds 提交于 
      Pull userns fix from Eric Biederman:
 "This contains just a single fix for a nasty oops"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  propogate_mnt: Handle the first propogated copy being a slave
      c5e0666c
    • L
      Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost · 3cedbec3
      由 Linus Torvalds 提交于 
      Pull virtio/qemu fixes from Michael Tsirkin:
 "A couple of fixes for virtio and for the new QEMU fw cfg driver"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio: Silence uninitialized variable warning
  firmware: qemu_fw_cfg.c: potential unintialized variable
      3cedbec3
    • E
      propogate_mnt: Handle the first propogated copy being a slave · 5ec0811d
      由 Eric W. Biederman 提交于 
      When the first propgated copy was a slave the following oops would result:
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
> IP: [<ffffffff811fba4e>] propagate_one+0xbe/0x1c0
> PGD bacd4067 PUD bac66067 PMD 0
> Oops: 0000 [#1] SMP
> Modules linked in:
> CPU: 1 PID: 824 Comm: mount Not tainted 4.6.0-rc5userns+ #1523
> Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
> task: ffff8800bb0a8000 ti: ffff8800bac3c000 task.ti: ffff8800bac3c000
> RIP: 0010:[<ffffffff811fba4e>]  [<ffffffff811fba4e>] propagate_one+0xbe/0x1c0
> RSP: 0018:ffff8800bac3fd38  EFLAGS: 00010283
> RAX: 0000000000000000 RBX: ffff8800bb77ec00 RCX: 0000000000000010
> RDX: 0000000000000000 RSI: ffff8800bb58c000 RDI: ffff8800bb58c480
> RBP: ffff8800bac3fd48 R08: 0000000000000001 R09: 0000000000000000
> R10: 0000000000001ca1 R11: 0000000000001c9d R12: 0000000000000000
> R13: ffff8800ba713800 R14: ffff8800bac3fda0 R15: ffff8800bb77ec00
> FS:  00007f3c0cd9b7e0(0000) GS:ffff8800bfb00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000010 CR3: 00000000bb79d000 CR4: 00000000000006e0
> Stack:
>  ffff8800bb77ec00 0000000000000000 ffff8800bac3fd88 ffffffff811fbf85
>  ffff8800bac3fd98 ffff8800bb77f080 ffff8800ba713800 ffff8800bb262b40
>  0000000000000000 0000000000000000 ffff8800bac3fdd8 ffffffff811f1da0
> Call Trace:
>  [<ffffffff811fbf85>] propagate_mnt+0x105/0x140
>  [<ffffffff811f1da0>] attach_recursive_mnt+0x120/0x1e0
>  [<ffffffff811f1ec3>] graft_tree+0x63/0x70
>  [<ffffffff811f1f6b>] do_add_mount+0x9b/0x100
>  [<ffffffff811f2c1a>] do_mount+0x2aa/0xdf0
>  [<ffffffff8117efbe>] ? strndup_user+0x4e/0x70
>  [<ffffffff811f3a45>] SyS_mount+0x75/0xc0
>  [<ffffffff8100242b>] do_syscall_64+0x4b/0xa0
>  [<ffffffff81988f3c>] entry_SYSCALL64_slow_path+0x25/0x25
> Code: 00 00 75 ec 48 89 0d 02 22 22 01 8b 89 10 01 00 00 48 89 05 fd 21 22 01 39 8e 10 01 00 00 0f 84 e0 00 00 00 48 8b 80 d8 00 00 00 <48> 8b 50 10 48 89 05 df 21 22 01 48 89 15 d0 21 22 01 8b 53 30
> RIP  [<ffffffff811fba4e>] propagate_one+0xbe/0x1c0
>  RSP <ffff8800bac3fd38>
> CR2: 0000000000000010
> ---[ end trace 2725ecd95164f217 ]---

This oops happens with the namespace_sem held and can be triggered by
non-root users.  An all around not pleasant experience.

To avoid this scenario when finding the appropriate source mount to
copy stop the walk up the mnt_master chain when the first source mount
is encountered.

Further rewrite the walk up the last_source mnt_master chain so that
it is clear what is going on.

The reason why the first source mount is special is that it it's
mnt_parent is not a mount in the dest_mnt propagation tree, and as
such termination conditions based up on the dest_mnt mount propgation
tree do not make sense.

To avoid other kinds of confusion last_dest is not changed when
computing last_source.  last_dest is only used once in propagate_one
and that is above the point of the code being modified, so changing
the global variable is meaningless and confusing.

Cc: stable@vger.kernel.org
fixes: f2ebb3a9 ("smarter propagate_mnt()")
Reported-by: NTycho Andersen <tycho.andersen@canonical.com>
Reviewed-by: NSeth Forshee <seth.forshee@canonical.com>
Tested-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
      5ec0811d
    • L
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input · 21a9703d
      由 Linus Torvalds 提交于 
      Pull input fixes from Dmitry Torokhov.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: atmel_mxt_ts - use mxt_acquire_irq in mxt_soft_reset
  Input: zforce_ts - fix dual touch recognition
  Input: twl6040-vibra - fix atomic schedule panic
      21a9703d
    • L
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security · 4810d968
      由 Linus Torvalds 提交于 
      Pull IMA fix from James Morris.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  ima: fix the string representation of the LSM/IMA hook enumeration ordering
      4810d968
    • L
      Merge tag 'for-linus-4.6-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip · 41143b77
      由 Linus Torvalds 提交于 
      Pull xen regression fixes from David Vrabel:

 - Fix two regressions causing crashes in 32-bit PV guests

 - Fix a regression in the evtchn driver

* tag 'for-linus-4.6-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/evtchn: fix ring resize when binding new events
  xen/balloon: Fix crash when ballooning on x86 32 bit PAE
  xen: Fix page <-> pfn conversion on 32 bit systems
      41143b77
  5. 04 5月, 2016 21 次提交