Skip to content

L
linux
Switch branch/tag
  1. 17 Apr, 2013 13 commits
  3. 15 Apr, 2013 2 commits
    • Michael Holzheu's avatar
      s390/kdump: Add PM notifier for kdump · b66ac63e
      Michael Holzheu authored 
      For s390 the page table mapping for the crashkernel memory is removed to
protect the pre-loaded kdump kernel and ramdisk. Because the crashkernel
memory is not included in the page tables for suspend/resume it is not
included in the suspend image. Therefore after resume the resumed system
does no longer contain the pre-loaded kdump kernel and when kdump is
triggered it fails.

This patch adds a PM notifier that creates the page tables before suspend
is done and removes them for resume. This ensures that the kdump kernel
is included in the suspend image.
Signed-off-by: default avatarMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      b66ac63e
    • Linus Torvalds's avatar
      Linux 3.9-rc7 · 41ef2d56
      Linus Torvalds authored
      41ef2d56
  5. 14 Apr, 2013 10 commits
  7. 13 Apr, 2013 3 commits
    • Suleiman Souhlal's avatar
      vfs: Revert spurious fix to spinning prevention in prune_icache_sb · 5b55d708
      Suleiman Souhlal authored 
      Revert commit 62a3ddef ("vfs: fix spinning prevention in prune_icache_sb").

This commit doesn't look right: since we are looking at the tail of the
list (sb->s_inode_lru.prev) if we want to skip an inode, we should put
it back at the head of the list instead of the tail, otherwise we will
keep spinning on it.

Discovered when investigating why prune_icache_sb came top in perf
reports of a swapping load.
Signed-off-by: default avatarSuleiman Souhlal <suleiman@google.com>
Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org # v3.2+
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5b55d708
    • Linus Torvalds's avatar
      kobject: fix kset_find_obj() race with concurrent last kobject_put() · a49b7e82
      Linus Torvalds authored 
      Anatol Pomozov identified a race condition that hits module unloading
and re-loading.  To quote Anatol:

 "This is a race codition that exists between kset_find_obj() and
  kobject_put().  kset_find_obj() might return kobject that has refcount
  equal to 0 if this kobject is freeing by kobject_put() in other
  thread.

  Here is timeline for the crash in case if kset_find_obj() searches for
  an object tht nobody holds and other thread is doing kobject_put() on
  the same kobject:

    THREAD A (calls kset_find_obj())     THREAD B (calls kobject_put())
    splin_lock()
                                         atomic_dec_return(kobj->kref), counter gets zero here
                                         ... starts kobject cleanup ....
                                         spin_lock() // WAIT thread A in kobj_kset_leave()
    iterate over kset->list
    atomic_inc(kobj->kref) (counter becomes 1)
    spin_unlock()
                                         spin_lock() // taken
                                         // it does not know that thread A increased counter so it
                                         remove obj from list
                                         spin_unlock()
                                         vfree(module) // frees module object with containing kobj

    // kobj points to freed memory area!!
    kobject_put(kobj) // OOPS!!!!

  The race above happens because module.c tries to use kset_find_obj()
  when somebody unloads module.  The module.c code was introduced in
  commit 6494a93d"

Anatol supplied a patch specific for module.c that worked around the
problem by simply not using kset_find_obj() at all, but rather than make
a local band-aid, this just fixes kset_find_obj() to be thread-safe
using the proper model of refusing the get a new reference if the
refcount has already dropped to zero.

See examples of this proper refcount handling not only in the kref
documentation, but in various other equivalent uses of this pattern by
grepping for atomic_inc_not_zero().

[ Side note: the module race does indicate that module loading and
  unloading is not properly serialized wrt sysfs information using the
  module mutex.  That may require further thought, but this is the
  correct fix at the kobject layer regardless. ]
Reported-analyzed-and-tested-by: default avatarAnatol Pomozov <anatol.pomozov@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a49b7e82
    • Josef Bacik's avatar
      Btrfs: make sure nbytes are right after log replay · 4bc4bee4
      Josef Bacik authored 
      While trying to track down a tree log replay bug I noticed that fsck was always
complaining about nbytes not being right for our fsynced file.  That is because
the new fsync stuff doesn't wait for ordered extents to complete, so the inodes
nbytes are not necessarily updated properly when we log it.  So to fix this we
need to set nbytes to whatever it is on the inode that is on disk, so when we
replay the extents we can just add the bytes that are being added as we replay
the extent.  This makes it work for the case that we have the wrong nbytes or
the case that we logged everything and nbytes is actually correct.  With this
I'm no longer getting nbytes errors out of btrfsck.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
Signed-off-by: default avatarChris Mason <chris.mason@fusionio.com>
      4bc4bee4
  9. 12 Apr, 2013 12 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7