linux_dsm_epyc7002/include
Linus Torvalds 143c97cc65 Revert "pty: fix the cached path of the pty slave file descriptor in the master"
This reverts commit c8c03f1858.

It turns out that while fixing the ptmx file descriptor to have the
correct 'struct path' to the associated slave pty is a really good
thing, it breaks some user space tools for a very annoying reason.

The problem is that /dev/ptmx and its associated slave pty (/dev/pts/X)
are on different mounts.  That was what caused us to have the wrong path
in the first place (we would mix up the vfsmount of the 'ptmx' node,
with the dentry of the pty slave node), but it also means that now while
we use the right vfsmount, having the pty master open also keeps the pts
mount busy.

And it turn sout that that makes 'pbuilder' very unhappy, as noted by
Stefan Lippers-Hollmann:

 "This patch introduces a regression for me when using pbuilder
  0.228.7[2] (a helper to build Debian packages in a chroot and to
  create and update its chroots) when trying to umount /dev/ptmx (inside
  the chroot) on Debian/ unstable (full log and pbuilder configuration
  file[3] attached).

  [...]
  Setting up build-essential (12.3) ...
  Processing triggers for libc-bin (2.24-15) ...
  I: unmounting dev/ptmx filesystem
  W: Could not unmount dev/ptmx: umount: /var/cache/pbuilder/build/1340/dev/ptmx: target is busy
          (In some cases useful info about processes that
           use the device is found by lsof(8) or fuser(1).)"

apparently pbuilder tries to unmount the /dev/pts filesystem while still
holding at least one master node open, which is arguably not very nice,
but we don't break user space even when fixing other bugs.

So this commit has to be reverted.

I'll try to figure out a way to avoid caching the path to the slave pty
in the master pty.  The only thing that actually wants that slave pty
path is the "TIOCGPTPEER" ioctl, and I think we could just recreate the
path at that time.

Reported-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: Eric W Biederman <ebiederm@xmission.com>
Cc: Christian Brauner <christian.brauner@canonical.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-23 18:16:11 -07:00
..
acpi ACPI: NUMA: add missing include in acpi_numa.h 2017-07-24 22:27:43 +02:00
asm-generic mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem 2017-08-10 15:54:07 -07:00
clocksource
crypto
drm i915, amd and some core fixes + mediatek color support 2017-07-13 11:26:18 -07:00
dt-bindings Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-07-15 10:59:54 -07:00
keys
kvm KVM: arm/arm64: PMU: Fix overflow interrupt injection 2017-07-25 14:18:01 +01:00
linux Revert "pty: fix the cached path of the pty slave file descriptor in the master" 2017-08-23 18:16:11 -07:00
math-emu
media media: platform: davinci: drop VPFE_CMD_S_CCDC_RAW_PARAMS 2017-07-26 06:14:33 -04:00
memory
misc
net net_sched: fix order of queue length updates in qdisc_replace() 2017-08-20 20:02:00 -07:00
pcmcia
ras
rdma IB/cma: Fix reference count leak when no ipv4 addresses are set 2017-07-20 11:24:13 -04:00
rxrpc
scsi SCSI fixes on 20170823 2017-08-23 11:34:40 -07:00
soc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-07-05 12:31:59 -07:00
sound ASoC: fix pcm-creation regression 2017-07-17 15:50:32 +01:00
target iscsi-target: Fix iscsi_np reset hung task during parallel delete 2017-08-06 14:41:41 -07:00
trace ext4: remove unused metadata accounting variables 2017-07-30 22:30:11 -04:00
uapi drm/msm: Remove __user from __u64 data types 2017-08-01 19:11:48 -04:00
video
xen xen/balloon: don't online new memory initially 2017-07-23 08:13:18 +02:00