vfs: In d_path don't call d_dname on a mount point

Aditya Kali (adityakali@google.com) wrote:
> Commit bf056bfa80596a5d14b26b17276a56a0dcb080e5:
> "proc: Fix the namespace inode permission checks." converted
> the namespace files into symlinks. The same commit changed
> the way namespace bind mounts appear in /proc/mounts:
>   $ mount --bind /proc/self/ns/ipc /mnt/ipc
> Originally:
>   $ cat /proc/mounts | grep ipc
>   proc /mnt/ipc proc rw,nosuid,nodev,noexec 0 0
>
> After commit bf056bfa80596a5d14b26b17276a56a0dcb080e5:
>   $ cat /proc/mounts | grep ipc
>   proc ipc:[4026531839] proc rw,nosuid,nodev,noexec 0 0
>
> This breaks userspace which expects the 2nd field in
> /proc/mounts to be a valid path.

The symlink /proc/<pid>/ns/{ipc,mnt,net,pid,user,uts} point to
dentries allocated with d_alloc_pseudo that we can mount, and
that have interesting names printed out with d_dname.

When these files are bind mounted /proc/mounts is not currently
displaying the mount point correctly because d_dname is called instead
of just displaying the path where the file is mounted.

Solve this by adding an explicit check to distinguish mounted pseudo
inodes and unmounted pseudo inodes.  Unmounted pseudo inodes always
use mount of their filesstem as the mnt_root  in their path making
these two cases easy to distinguish.

CC: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reported-by: Aditya Kali <adityakali@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
fork:  Allow CLONE_PARENT after setns(CLONE_NEWPID)

Serge Hallyn <serge.hallyn@ubuntu.com> writes:
> Hi Oleg,
>
> commit 40a0d32d1eaffe6aac7324ca92604b6b3977eb0e :
> "fork: unify and tighten up CLONE_NEWUSER/CLONE_NEWPID checks"
> breaks lxc-attach in 3.12.  That code forks a child which does
> setns() and then does a clone(CLONE_PARENT).  That way the
> grandchild can be in the right namespaces (which the child was
> not) and be a child of the original task, which is the monitor.
>
> lxc-attach in 3.11 was working fine with no side effects that I
> could see.  Is there a real danger in allowing CLONE_PARENT
> when current->nsproxy->pidns_for_children is not our pidns,
> or was this done out of an "over-abundance of caution"?  Can we
> safely revert that new extra check?

The two fundamental things I know we can not allow are:
- A shared signal queue aka CLONE_THREAD.  Because we compute the pid
  and uid of the signal when we place it in the queue.

- Changing the pid and by extention pid_namespace of an existing
  process.

From a parents perspective there is nothing special about the pid
namespace, to deny CLONE_PARENT, because the parent simply won't know or
care.

From the childs perspective all that is special really are shared signal
queues.

User mode threading with CLONE_PARENT|CLONE_VM|CLONE_SIGHAND and tasks
in different pid namespaces is almost certainly going to break because
it is complicated.  But shared signal handlers can look at per thread
information to know which pid namespace a process is in, so I don't know
of any reason not to support CLONE_PARENT|CLONE_VM|CLONE_SIGHAND threads
at the kernel level.  It would be absolutely stupid to implement but
that is a different thing.

So hmm.

Because it can do no harm, and because it is a regression let's remove
the CLONE_PARENT check and send it stable.

Cc: stable@vger.kernel.org
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
vfs: Fix a regression in mounting proc

Gao feng <gaofeng@cn.fujitsu.com> reported that commit
e51db73532955dc5eaba4235e62b74b460709d5b
userns: Better restrictions on when proc and sysfs can be mounted
caused a regression on mounting a new instance of proc in a mount
namespace created with user namespace privileges, when binfmt_misc
is mounted on /proc/sys/fs/binfmt_misc.

This is an unintended regression caused by the absolutely bogus empty
directory check in fs_fully_visible.  The check fs_fully_visible replaced
didn't even bother to attempt to verify proc was fully visible and
hiding proc files with any kind of mount is rare.  So for now fix
the userspace regression by allowing directory with nlink == 1
as /proc/sys/fs/binfmt_misc has.

I will have a better patch but it is not stable material, or
last minute kernel material.  So it will have to wait.

Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Gao feng <gaofeng@cn.fujitsu.com>
Tested-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
ath10k: fix WEP Shared authentication

Frames received from FW were treated incorrectly.
This led to stations being unable to associate to
WEP Shared ath10k AP. This was indicated by a
bizarre hostapd message:

  Unsupported authentication algorithm (36088)

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
writeback: Fix data corruption on NFS

Commit 4f8ad655dbc8 "writeback: Refactor writeback_single_inode()" added
a condition to skip clean inode. However this is wrong in WB_SYNC_ALL
mode because there we also want to wait for outstanding writeback on
possibly clean inode. This was causing occasional data corruption issues
on NFS because it uses sync_inode() to make sure all outstanding writes
are flushed to the server before truncating the inode and with
sync_inode() returning prematurely file was sometimes extended back
by an outstanding write after it was truncated.

So modify the test to also check for pages under writeback in
WB_SYNC_ALL mode.

CC: stable@vger.kernel.org # >= 3.5
Fixes: 4f8ad655dbc82cf05d2edc11e66b78a42d38bf93
Reported-and-tested-by: Dan Duval <dan.duval@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
ath10k: handle TKIP MIC error correctly

We should check MIC error flag base on
rx_attention, to have consistent status
of MIC failure and FCS error.

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: fix band reporting for mgmt CCK frames on 5GHz

Although CCK modulation isn't expected for 11a if
it happened it made ath10k report wrong band
(2GHz) for a mgmt frame that were actually
received on 5Ghz band. Frequency would also
decoded incorrectly too.

In case of 5GHz-only devices this triggered
mac80211 WARN_ON because there was no according
sband pointer to be found.

The patch should fix delivery of such frames by
using different means to acquire band parameter.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: split the if_limits and if_comb

Split the interface limits and inteface combination,
to reflect the 10.X capabilites (no P2P, no STA and 8 VAP).

kvalo: reverse order of ATH10K_FW_FEATURE_WMI_10X test, fix
checkpath warnings

Signed-off-by: Bartosz Markowski <bartosz.markowski@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: introduce NO_P2P fw feature flag

Not each ath10k FW track supports P2P (10.X for instance does not)
This new firmware feature flag allows to turn off P2P interface type.

Signed-off-by: Bartosz Markowski <bartosz.markowski@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Merge remote-tracking branch 'wireless-next/master' into ath-next
clocksource: cadence_ttc: Fix mutex taken inside interrupt context

When the kernel is compiled with:
CONFIG_HIGH_RES_TIMERS=no
CONFIG_HZ_PERIODIC=yes
CONFIG_DEBUG_ATOMIC_SLEEP=yes

The following WARN appears:

WARNING: CPU: 1 PID: 0 at linux/kernel/mutex.c:856 mutex_trylock+0x70/0x1fc()
DEBUG_LOCKS_WARN_ON(in_interrupt())
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.12.0-xilinx-dirty #93
[<c0014a78>] (unwind_backtrace+0x0/0x11c) from [<c0011b6c>] (show_stack+0x10/0x14)
[<c0011b6c>] (show_stack+0x10/0x14) from [<c039120c>] (dump_stack+0x7c/0xc0)
[<c039120c>] (dump_stack+0x7c/0xc0) from [<c001fda4>] (warn_slowpath_common+0x60/0x84)
[<c001fda4>] (warn_slowpath_common+0x60/0x84) from [<c001fe48>] (warn_slowpath_fmt+0x2c/0x3c)
[<c001fe48>] (warn_slowpath_fmt+0x2c/0x3c) from [<c0392658>] (mutex_trylock+0x70/0x1fc)
[<c0392658>] (mutex_trylock+0x70/0x1fc) from [<c02dfc08>] (clk_prepare_lock+0xc/0xe4)
[<c02dfc08>] (clk_prepare_lock+0xc/0xe4) from [<c02e099c>] (clk_get_rate+0xc/0x44)
[<c02e099c>] (clk_get_rate+0xc/0x44) from [<c02d0394>] (ttc_set_mode+0x34/0x78)
[<c02d0394>] (ttc_set_mode+0x34/0x78) from [<c005f794>] (clockevents_set_mode+0x28/0x5c)
[<c005f794>] (clockevents_set_mode+0x28/0x5c) from [<c00607fc>] (tick_broadcast_on_off+0x190/0x1c0)
[<c00607fc>] (tick_broadcast_on_off+0x190/0x1c0) from [<c005f168>] (clockevents_notify+0x58/0x1ac)
[<c005f168>] (clockevents_notify+0x58/0x1ac) from [<c02b99dc>] (cpuidle_setup_broadcast_timer+0x20/0x24)
[<c02b99dc>] (cpuidle_setup_broadcast_timer+0x20/0x24) from [<c006cd04>] (generic_smp_call_function_single_interrupt+0)
[<c006cd04>] (generic_smp_call_function_single_interrupt+0xe0/0x130) from [<c00138c8>] (handle_IPI+0x88/0x118)
[<c00138c8>] (handle_IPI+0x88/0x118) from [<c0008504>] (gic_handle_irq+0x58/0x60)
[<c0008504>] (gic_handle_irq+0x58/0x60) from [<c0012644>] (__irq_svc+0x44/0x78)
Exception stack(0xef099fa0 to 0xef099fe8)
9fa0: 00000001 ef092100 00000000 ef092100 ef098000 00000015 c0399f2c c0579d74
9fc0: 0000406a 413fc090 00000000 00000000 00000000 ef099fe8 c00666ec c000f46c
9fe0: 20000113 ffffffff
[<c0012644>] (__irq_svc+0x44/0x78) from [<c000f46c>] (arch_cpu_idle+0x34/0x3c)
[<c000f46c>] (arch_cpu_idle+0x34/0x3c) from [<c0053980>] (cpu_startup_entry+0xa8/0x10c)
[<c0053980>] (cpu_startup_entry+0xa8/0x10c) from [<000085a4>] (0x85a4)

We are in an interrupt context (IPI) and we are calling clk_get_rate in the
set_mode function which in turn ends up by getting a mutex... Even if that
does not hang, it is a potential kernel deadlock.

It is not allowed to call clk_get_rate() from interrupt context. To
avoid such calls the timer input frequency is stored in the driver's
data struct which makes it accessible to the driver in any context.

[dlezcano] completed the changelog with the WARN trace and added a more
detailed description. Tested on zync zc702.

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
cfg80211/mac80211: correct qos-map locking

Since the RTNL can't always be held, use wdev/sdata locking for
the qos-map dereference in mac80211. This requires cfg80211 to
consistently lock it, which it was missing in one place.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
NFC: mei_phy: Using kfree_skb() instead of kfree()

Using kfree_skb() instead of kfree() for struct sk_buff

Signed-off-by: Salil Kapur <salilkapur93@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFC: pn544: Refactor hw_config values

Some of the EEPROM configurations that are assigned by the PN544 driver
are set by the firmware and should not be modified by the driver. Others
are certain user mode configurations that are currently getting set to values
that shouldn't necessarily be dictated by the driver. This patch changes
most user and system mode configurations to the firmware defaults.

Signed-off-by: Arman Uguray <armansito@chromium.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFC: Return driver failure upon unknown event reception

If the device is polling, this will trigger a netlink event to notify
userspace about the polling error.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFC: llcp: Fix possible memory leak while sending I frames

If sending was not completed due to low memory condition msg_data
was not free before returning from function.

Signed-off-by: Szymon Janc <szymon.janc@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFC: llcp: Use default MIU if none was specified on connect

If MIUX is not present in CONNECT or CC use default MIU value (128)
instead of one announced durring link setup.

This was affecting Bluetooth handover with Android 4.3+ NCI stack.

Signed-off-by: Szymon Janc <szymon.janc@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFC: Only warn on SE discovery error

SE discovery errors are currently overwriting the dev_up() return error.
This is wrong for many reasons:

- We don't want to report an error if we actually brought the device up
  but it failed to discover SEs. By doing so we pretend we don't have an
  NFC functional device even we do. The only thing we could not do was
  checking for SEs availability. This is the false negative case.

- In some cases the actual device power up failed but the SE discovery
  succeeded. Userspace then believes the device is up while it's not.
  This is the false positive case.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFC: pn533: Frame is invalid if ccid.datalen is 0

Some ACR122 firmwares seem to send 0 length data frames. Before using
that length as a data index, we check that it's not 0. If it is we
report the frame as being invalid.

Reported-by: Arthur Taylor <arthur@advancedtelematic.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFC: digital: Add a note about asynchronous functions

This explains how and why the timeout parameter must be handled by the
driver implementation.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>