Skip to content

L
linux
Switch branch/tag
  1. 24 Dec, 2018 16 commits
  3. 23 Dec, 2018 2 commits
  5. 22 Dec, 2018 5 commits
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 9105b8aa
      Linus Torvalds authored 
      Pull SCSI fixes from James Bottomley:
 "This is two simple target fixes and one discard related I/O starvation
  problem in sd.

  The discard problem occurs because the discard page doesn't have a
  mempool backing so if the allocation fails due to memory pressure, we
  then lose the forward progress we require if the writeout is on the
  same device. The fix is to back it with a mempool"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: sd: use mempool for discard special page
  scsi: target: iscsi: cxgbit: add missing spin_lock_init()
  scsi: target: iscsi: cxgbit: fix csk leak
      9105b8aa
    • Linus Torvalds's avatar
      Merge tag 'compiler-attributes-for-linus-v4.20' of https://github.com/ojeda/linux · 1104bd96
      Linus Torvalds authored 
      Pull compiler_types.h fix from Miguel Ojeda:
 "A cleanup for userspace in compiler_types.h: don't pollute userspace
  with macro definitions (Xiaozhou Liu)

  This is harmless for the kernel, but v4.19 was released with a few
  macros exposed to userspace as the patch explains; which this removes,
  so it *could* happen that we break something for someone (although
  leaving inline redefined is probably worse)"

* tag 'compiler-attributes-for-linus-v4.20' of https://github.com/ojeda/linux:
  include/linux/compiler_types.h: don't pollute userspace with macro definitions
      1104bd96
    • Linus Torvalds's avatar
      Merge tag 'auxdisplay-for-linus-v4.20' of https://github.com/ojeda/linux · 38c0ecf6
      Linus Torvalds authored 
      Pull auxdisplay fix from Miguel Ojeda:
 "charlcd: fix x/y command parsing (Mans Rullgard)"

* tag 'auxdisplay-for-linus-v4.20' of https://github.com/ojeda/linux:
  auxdisplay: charlcd: fix x/y command parsing
      38c0ecf6
    • Christian Brauner's avatar
      Revert "vfs: Allow userns root to call mknod on owned filesystems." · 94f82008
      Christian Brauner authored 
      This reverts commit 55956b59.

commit 55956b59 ("vfs: Allow userns root to call mknod on owned filesystems.")
enabled mknod() in user namespaces for userns root if CAP_MKNOD is
available. However, these device nodes are useless since any filesystem
mounted from a non-initial user namespace will set the SB_I_NODEV flag on
the filesystem. Now, when a device node s created in a non-initial user
namespace a call to open() on said device node will fail due to:

bool may_open_dev(const struct path *path)
{
        return !(path->mnt->mnt_flags & MNT_NODEV) &&
                !(path->mnt->mnt_sb->s_iflags & SB_I_NODEV);
}

The problem with this is that as of the aforementioned commit mknod()
creates partially functional device nodes in non-initial user namespaces.
In particular, it has the consequence that as of the aforementioned commit
open() will be more privileged with respect to device nodes than mknod().
Before it was the other way around. Specifically, if mknod() succeeded
then it was transparent for any userspace application that a fatal error
must have occured when open() failed.

All of this breaks multiple userspace workloads and a widespread assumption
about how to handle mknod(). Basically, all container runtimes and systemd
live by the slogan "ask for forgiveness not permission" when running user
namespace workloads. For mknod() the assumption is that if the syscall
succeeds the device nodes are useable irrespective of whether it succeeds
in a non-initial user namespace or not. This logic was chosen explicitly
to allow for the glorious day when mknod() will actually be able to create
fully functional device nodes in user namespaces.
A specific problem people are already running into when running 4.18 rc
kernels are failing systemd services. For any distro that is run in a
container systemd services started with the PrivateDevices= property set
will fail to start since the device nodes in question cannot be
opened (cf. the arguments in [1]).

Full disclosure, Seth made the very sound argument that it is already
possible to end up with partially functional device nodes. Any filesystem
mounted with MS_NODEV set will allow mknod() to succeed but will not allow
open() to succeed. The difference to the case here is that the MS_NODEV
case is transparent to userspace since it is an explicitly set mount option
while the SB_I_NODEV case is an implicit property enforced by the kernel
and hence opaque to userspace.

[1]: https://github.com/systemd/systemd/pull/9483Signed-off-by: default avatarChristian Brauner <christian@brauner.io>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Serge Hallyn <serge@hallyn.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      94f82008
    • Christoph Hellwig's avatar
      dma-mapping: fix flags in dma_alloc_wc · 0cd60eb1
      Christoph Hellwig authored 
      We really need the writecombine flag in dma_alloc_wc, fix a stupid
oversight.

Fixes: 7ed1d91a ("dma-mapping: translate __GFP_NOFAIL to DMA_ATTR_NO_WARN")
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0cd60eb1
  7. 21 Dec, 2018 17 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7