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  1. 21 Apr, 2016 2 commits
    • Gerald Schaefer's avatar
      s390/mm: fix asce_bits handling with dynamic pagetable levels · 723cacbd
      Gerald Schaefer authored 
      There is a race with multi-threaded applications between context switch and
pagetable upgrade. In switch_mm() a new user_asce is built from mm->pgd and
mm->context.asce_bits, w/o holding any locks. A concurrent mmap with a
pagetable upgrade on another thread in crst_table_upgrade() could already
have set new asce_bits, but not yet the new mm->pgd. This would result in a
corrupt user_asce in switch_mm(), and eventually in a kernel panic from a
translation exception.

Fix this by storing the complete asce instead of just the asce_bits, which
can then be read atomically from switch_mm(), so that it either sees the
old value or the new value, but no mixture. Both cases are OK. Having the
old value would result in a page fault on access to the higher level memory,
but the fault handler would see the new mm->pgd, if it was a valid access
after the mmap on the other thread has completed. So as worst-case scenario
we would have a page fault loop for the racing thread until the next time
slice.

Also remove dead code and simplify the upgrade/downgrade path, there are no
upgrades from 2 levels, and only downgrades from 3 levels for compat tasks.
There are also no concurrent upgrades, because the mmap_sem is held with
down_write() in do_mmap, so the flush and table checks during upgrade can
be removed.
Reported-by: default avatarMichael Munday <munday@ca.ibm.com>
Reviewed-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      723cacbd
    • Sebastian Ott's avatar
      s390/pci: fix use after free in dma_init · dba59909
      Sebastian Ott authored 
      After a failure during registration of the dma_table (because of the
function being in error state) we free its memory but don't reset the
associated pointer to zero.

When we then receive a notification from firmware (about the function
being in error state) we'll try to walk and free the dma_table again.

Fix this by resetting the dma_table pointer. In addition to that make
sure that we free the iommu_bitmap when appropriate.
Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      dba59909
  3. 20 Apr, 2016 1 commit
  5. 19 Apr, 2016 2 commits
    • Linus Torvalds's avatar
      Merge branch 'ptmx-cleanup' · 9a0e3eea
      Linus Torvalds authored 
      Merge the ptmx internal interface cleanup branch.

This doesn't change semantics, but it should be a sane basis for
eventually getting the multi-instance devpts code into some sane shape
where we can get rid of the kernel config option.  Which we can
hopefully get done next merge window..

* ptmx-cleanup:
  devpts: clean up interface to pty drivers
      9a0e3eea
    • Linus Torvalds's avatar
      Merge tag 'pci-v4.6-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci · 12566cc3
      Linus Torvalds authored 
      Pull PCI fixes from Bjorn Helgaas:
 "These are fixes for two issues:

   - The VPD parsing code we added for v4.6 keeps some devices from
     crashing, but also keeps cxgb4 from reading non-standard extra VPD
     data that is relies on.  Hariprasad added a way for the driver to
     specify how much VPD is valid.

   - The i.MX6 active-low reset GPIO support we added in v4.5 caused
     regressions on some boards, so we're reverting that.

  VPD:
    Add pci_set_vpd_size() (Hariprasad Shenai)
    cxgb4: Set VPD size so we can read both VPD structures (Hariprasad Shenai)

  Freescale i.MX6 host bridge driver:
    Revert "PCI: imx6: Add support for active-low reset GPIO" (Fabio Estevam)"

* tag 'pci-v4.6-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  cxgb4: Set VPD size so we can read both VPD structures
  PCI: Add pci_set_vpd_size() to set VPD size
  Revert "PCI: imx6: Add support for active-low reset GPIO"
      12566cc3
  7. 18 Apr, 2016 3 commits
    • Linus Torvalds's avatar
      devpts: clean up interface to pty drivers · 67245ff3
      Linus Torvalds authored 
      This gets rid of the horrible notion of having that

    struct inode *ptmx_inode

be the linchpin of the interface between the pty code and devpts.

By de-emphasizing the ptmx inode, a lot of things actually get cleaner,
and we will have a much saner way forward.  In particular, this will
allow us to associate with any particular devpts instance at open-time,
and not be artificially tied to one particular ptmx inode.

The patch itself is actually fairly straightforward, and apart from some
locking and return path cleanups it's pretty mechanical:

 - the interfaces that devpts exposes all take "struct pts_fs_info *"
   instead of "struct inode *ptmx_inode" now.

   NOTE! The "struct pts_fs_info" thing is a completely opaque structure
   as far as the pty driver is concerned: it's still declared entirely
   internally to devpts. So the pty code can't actually access it in any
   way, just pass it as a "cookie" to the devpts code.

 - the "look up the pts fs info" is now a single clear operation, that
   also does the reference count increment on the pts superblock.

   So "devpts_add/del_ref()" is gone, and replaced by a "lookup and get
   ref" operation (devpts_get_ref(inode)), along with a "put ref" op
   (devpts_put_ref()).

 - the pty master "tty->driver_data" field now contains the pts_fs_info,
   not the ptmx inode.

 - because we don't care about the ptmx inode any more as some kind of
   base index, the ref counting can now drop the inode games - it just
   gets the ref on the superblock.

 - the pts_fs_info now has a back-pointer to the super_block. That's so
   that we can easily look up the information we actually need. Although
   quite often, the pts fs info was actually all we wanted, and not having
   to look it up based on some magical inode makes things more
   straightforward.

In particular, now that "devpts_get_ref(inode)" operation should really
be the *only* place we need to look up what devpts instance we're
associated with, and we do it exactly once, at ptmx_open() time.

The other side of this is that one ptmx node could now be associated
with multiple different devpts instances - you could have a single
/dev/ptmx node, and then have multiple mount namespaces with their own
instances of devpts mounted on /dev/pts/.  And that's all perfectly sane
in a model where we just look up the pts instance at open time.

This will eventually allow us to get rid of our odd single-vs-multiple
pts instance model, but this patch in itself changes no semantics, only
an internal binding model.

Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: Jann Horn <jann@thejh.net>
Cc: Greg KH <greg@kroah.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      67245ff3
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux · 95d0c427
      Linus Torvalds authored 
      Pull s390 fixes from Martin Schwidefsky:
 "A couple of bug fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390: add CPU_BIG_ENDIAN config option
  s390/spinlock: avoid yield to non existent cpu
  s390/dcssblk: fix possible deadlock in remove vs. per-device attributes
  s390/seccomp: include generic seccomp header file
  s390/pci: add extra padding to function measurement block
  s390/scm_blk: fix deadlock for requests != REQ_TYPE_FS
      95d0c427
    • Linus Torvalds's avatar
      Linux 4.6-rc4 · c3b46c73
      Linus Torvalds authored
      c3b46c73
  9. 17 Apr, 2016 5 commits
  11. 16 Apr, 2016 7 commits
  13. 15 Apr, 2016 20 commits
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