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  1. 06 Nov, 2013 8 commits
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  5. 02 Nov, 2013 2 commits
  7. 01 Nov, 2013 22 commits
  9. 31 Oct, 2013 5 commits
    • Linus Torvalds's avatar
      Merge branch 'akpm' (fixes from Andrew Morton) · 4f794ee8
      Linus Torvalds authored 
      Merge four more fixes from Andrew Morton.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  lib/scatterlist.c: don't flush_kernel_dcache_page on slab page
  mm: memcg: fix test for child groups
  mm: memcg: lockdep annotation for memcg OOM lock
  mm: memcg: use proper memcg in limit bypass
      4f794ee8
    • Ming Lei's avatar
      lib/scatterlist.c: don't flush_kernel_dcache_page on slab page · 3d77b50c
      Ming Lei authored 
      Commit b1adaf65 ("[SCSI] block: add sg buffer copy helper
functions") introduces two sg buffer copy helpers, and calls
flush_kernel_dcache_page() on pages in SG list after these pages are
written to.

Unfortunately, the commit may introduce a potential bug:

 - Before sending some SCSI commands, kmalloc() buffer may be passed to
   block layper, so flush_kernel_dcache_page() can see a slab page
   finally

 - According to cachetlb.txt, flush_kernel_dcache_page() is only called
   on "a user page", which surely can't be a slab page.

 - ARCH's implementation of flush_kernel_dcache_page() may use page
   mapping information to do optimization so page_mapping() will see the
   slab page, then VM_BUG_ON() is triggered.

Aaro Koskinen reported the bug on ARM/kirkwood when DEBUG_VM is enabled,
and this patch fixes the bug by adding test of '!PageSlab(miter->page)'
before calling flush_kernel_dcache_page().
Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
Reported-by: default avatarAaro Koskinen <aaro.koskinen@iki.fi>
Tested-by: default avatarSimon Baatz <gmbnomis@gmail.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Tejun Heo <tj@kernel.org>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>	[3.2+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3d77b50c
    • Johannes Weiner's avatar
      mm: memcg: fix test for child groups · 696ac172
      Johannes Weiner authored 
      When memcg code needs to know whether any given memcg has children, it
uses the cgroup child iteration primitives and returns true/false
depending on whether the iteration loop is executed at least once or
not.

Because a cgroup's list of children is RCU protected, these primitives
require the RCU read-lock to be held, which is not the case for all
memcg callers.  This results in the following splat when e.g.  enabling
hierarchy mode:

  WARNING: CPU: 3 PID: 1 at kernel/cgroup.c:3043 css_next_child+0xa3/0x160()
  CPU: 3 PID: 1 Comm: systemd Not tainted 3.12.0-rc5-00117-g83f11a9c-dirty #18
  Hardware name: LENOVO 3680B56/3680B56, BIOS 6QET69WW (1.39 ) 04/26/2012
  Call Trace:
    dump_stack+0x54/0x74
    warn_slowpath_common+0x78/0xa0
    warn_slowpath_null+0x1a/0x20
    css_next_child+0xa3/0x160
    mem_cgroup_hierarchy_write+0x5b/0xa0
    cgroup_file_write+0x108/0x2a0
    vfs_write+0xbd/0x1e0
    SyS_write+0x4c/0xa0
    system_call_fastpath+0x16/0x1b

In the memcg case, we only care about children when we are attempting to
modify inheritable attributes interactively.  Racing with deletion could
mean a spurious -EBUSY, no problem.  Racing with addition is handled
just fine as well through the memcg_create_mutex: if the child group is
not on the list after the mutex is acquired, it won't be initialized
from the parent's attributes until after the unlock.
Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      696ac172
    • Johannes Weiner's avatar
      mm: memcg: lockdep annotation for memcg OOM lock · 0056f4e6
      Johannes Weiner authored 
      The memcg OOM lock is a mutex-type lock that is open-coded due to
memcg's special needs.  Add annotations for lockdep coverage.
Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0056f4e6
    • Johannes Weiner's avatar
      mm: memcg: use proper memcg in limit bypass · 3168ecbe
      Johannes Weiner authored 
      Commit 84235de3 ("fs: buffer: move allocation failure loop into the
allocator") allowed __GFP_NOFAIL allocations to bypass the limit if they
fail to reclaim enough memory for the charge.  But because the main test
case was on a 3.2-based system, the patch missed the fact that on newer
kernels the charge function needs to return root_mem_cgroup when
bypassing the limit, and not NULL.  This will corrupt whatever memory is
at NULL + percpu pointer offset.  Fix this quickly before problems are
reported.
Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3168ecbe
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