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  1. 05 Nov, 2012 3 commits
    • Jan Kara's avatar
      mm: fix XFS oops due to dirty pages without buffers on s390 · e418b3bb
      Jan Kara authored 
      commit ef5d437f upstream.

On s390 any write to a page (even from kernel itself) sets architecture
specific page dirty bit.  Thus when a page is written to via buffered
write, HW dirty bit gets set and when we later map and unmap the page,
page_remove_rmap() finds the dirty bit and calls set_page_dirty().

Dirtying of a page which shouldn't be dirty can cause all sorts of
problems to filesystems.  The bug we observed in practice is that
buffers from the page get freed, so when the page gets later marked as
dirty and writeback writes it, XFS crashes due to an assertion
BUG_ON(!PagePrivate(page)) in page_buffers() called from
xfs_count_page_state().

Similar problem can also happen when zero_user_segment() call from
xfs_vm_writepage() (or block_write_full_page() for that matter) set the
hardware dirty bit during writeback, later buffers get freed, and then
page unmapped.

Fix the issue by ignoring s390 HW dirty bit for page cache pages of
mappings with mapping_cap_account_dirty().  This is safe because for
such mappings when a page gets marked as writeable in PTE it is also
marked dirty in do_wp_page() or do_page_fault().  When the dirty bit is
cleared by clear_page_dirty_for_io(), the page gets writeprotected in
page_mkclean().  So pagecache page is writeable if and only if it is
dirty.

Thanks to Hugh Dickins for pointing out mapping has to have
mapping_cap_account_dirty() for things to work and proposing a cleaned
up variant of the patch.

The patch has survived about two hours of running fsx-linux on tmpfs
while heavily swapping and several days of running on out build machines
where the original problem was triggered.
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e418b3bb
    • Len Brown's avatar
      x86: Remove the ancient and deprecated disable_hlt() and enable_hlt() facility · 05e02741
      Len Brown authored 
      commit f6365201 upstream.

The X86_32-only disable_hlt/enable_hlt mechanism was used by the
32-bit floppy driver. Its effect was to replace the use of the
HLT instruction inside default_idle() with cpu_relax() - essentially
it turned off the use of HLT.

This workaround was commented in the code as:

 "disable hlt during certain critical i/o operations"

 "This halt magic was a workaround for ancient floppy DMA
  wreckage. It should be safe to remove."

H. Peter Anvin additionally adds:

 "To the best of my knowledge, no-hlt only existed because of
  flaky power distributions on 386/486 systems which were sold to
  run DOS.  Since DOS did no power management of any kind,
  including HLT, the power draw was fairly uniform; when exposed
  to the much hhigher noise levels you got when Linux used HLT
  caused some of these systems to fail.

  They were by far in the minority even back then."

Alan Cox further says:

 "Also for the Cyrix 5510 which tended to go castors up if a HLT
  occurred during a DMA cycle and on a few other boxes HLT during
  DMA tended to go astray.

  Do we care ? I doubt it. The 5510 was pretty obscure, the 5520
  fixed it, the 5530 is probably the oldest still in any kind of
  use."

So, let's finally drop this.
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
Signed-off-by: default avatarJosh Boyer <jwboyer@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatar"H. Peter Anvin" <hpa@zytor.com>
Acked-by: default avatarAlan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Stephen Hemminger <shemminger@vyatta.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-3rhk9bzf0x9rljkv488tloib@git.kernel.org
[ If anyone cares then alternative instruction patching could be
  used to replace HLT with a one-byte NOP instruction. Much simpler. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      05e02741
    • Herton Ronaldo Krzesinski's avatar
      floppy: do put_disk on current dr if blk_init_queue fails · 2000afe4
      Herton Ronaldo Krzesinski authored 
      commit 238ab784 upstream.

If blk_init_queue fails, we do not call put_disk on the current dr
(dr is decremented first in the error handling loop).
Reviewed-by: default avatarBen Hutchings <ben@decadent.org.uk>
Signed-off-by: default avatarHerton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      2000afe4
  3. 31 Oct, 2012 35 commits
  5. 28 Oct, 2012 2 commits
    • Greg Kroah-Hartman's avatar
      Linux 3.0.49 · d9ee258b
      Greg Kroah-Hartman authored
      d9ee258b
    • Elric Fu's avatar
      xHCI: handle command after aborting the command ring · 29b3f4e6
      Elric Fu authored 
      commit b63f4053 upstream.

According to xHCI spec section 4.6.1.1 and section 4.6.1.2,
after aborting a command on the command ring, xHC will
generate a command completion event with its completion
code set to Command Ring Stopped at least. If a command is
currently executing at the time of aborting a command, xHC
also generate a command completion event with its completion
code set to Command Abort. When the command ring is stopped,
software may remove, add, or rearrage Command Descriptors.

To cancel a command, software will initialize a command
descriptor for the cancel command, and add it into a
cancel_cmd_list of xhci. When the command ring is stopped,
software will find the command trbs described by command
descriptors in cancel_cmd_list and modify it to No Op
command. If software can't find the matched trbs, we can
think it had been finished.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ec "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Note from Sarah: The TRB_TYPE_LINK_LE32 macro is not in the 3.0 stable
kernel, so I added it to this patch.
Signed-off-by: default avatarElric Fu <elricfu1@gmail.com>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Tested-by: default avatarMiroslav Sabljic <miroslav.sabljic@avl.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      29b3f4e6
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