Pull arm64 fix from Will Deacon:
"Ensure PAN is re-enabled following user fault in uaccess routines.

After I thought we were done for 5.4, we had a report this week of a
nasty issue that has been shown to leak data between different user
address spaces thanks to corruption of entries in the TLB. In
hindsight, we should have spotted this in review when the PAN code was
merged back in v4.3, but hindsight is 20/20 and I'm trying not to beat
myself up too much about it despite being fairly miserable.

Anyway, the fix is "obvious" but the actual failure is more more
subtle, and is described in the commit message. I've included a fairly
mechanical follow-up patch here as well, which moves this checking out
into the C wrappers which is what we do for {get,put}_user() already
and allows us to remove these bloody assembly macros entirely. The
patches have passed kernelci [1] [2] [3] and CKI [4] tests over night,
as well as some targetted testing [5] for this particular issue.

The first patch is tagged for stable and should be applied to 4.14,
4.19 and 5.3. I have separate backports for 4.4 and 4.9, which I'll
send out once this has landed in your tree (although the original
patch applies cleanly, it won't build for those two trees).

Thanks to Pavel Tatashin for reporting this and Mark Rutland for
helping to diagnose the issue and review/test the solution"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: uaccess: Remove uaccess_*_not_uao asm macros
arm64: uaccess: Ensure PAN is re-enabled after unhandled uaccess fault

Pull block fix from Jens Axboe:
"Just a single fix for an issue in nbd introduced in this cycle"

* tag 'for-linus-20191121' of git://git.kernel.dk/linux-block:
nbd:fix memory leak in nbd_get_socket()

It is safer and simpler to drop the uaccess assembly macros in favour of
inline C functions. Although this bloats the Image size slightly, it
aligns our user copy routines with '{get,put}_user()' and generally
makes the code a lot easier to reason about.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
[will: tweaked commit message and changed temporary variable names]
Signed-off-by: Will Deacon <will@kernel.org>

Pull GPIO fixes from Linus Walleij:
"A last set of small fixes for GPIO, this cycle was quite busy.

- Fix debounce delays on the MAX77620 GPIO expander

- Use the correct unit for debounce times on the BD70528 GPIO expander

- Get proper deps for parallel builds of the GPIO tools

- Add a specific ACPI quirk for the Terra Pad 1061"

* tag 'gpio-v5.4-5' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
gpiolib: acpi: Add Terra Pad 1061 to the run_edge_events_on_boot_blacklist
tools: gpio: Correctly add make dependencies for gpio_utils
gpio: bd70528: Use correct unit for debounce times
gpio: max77620: Fixup debounce delays

Before returning NULL, put the sock first.

Cc: stable@vger.kernel.org
Fixes: cf1b2326b734 ("nbd: verify socket is supported during setup")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Sun Ke <sunke32@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

A number of our uaccess routines ('__arch_clear_user()' and
'__arch_copy_{in,from,to}_user()') fail to re-enable PAN if they
encounter an unhandled fault whilst accessing userspace.

For CPUs implementing both hardware PAN and UAO, this bug has no effect
when both extensions are in use by the kernel.

For CPUs implementing hardware PAN but not UAO, this means that a kernel
using hardware PAN may execute portions of code with PAN inadvertently
disabled, opening us up to potential security vulnerabilities that rely
on userspace access from within the kernel which would usually be
prevented by this mechanism. In other words, parts of the kernel run the
same way as they would on a CPU without PAN implemented/emulated at all.

For CPUs not implementing hardware PAN and instead relying on software
emulation via 'CONFIG_ARM64_SW_TTBR0_PAN=y', the impact is unfortunately
much worse. Calling 'schedule()' with software PAN disabled means that
the next task will execute in the kernel using the page-table and ASID
of the previous process even after 'switch_mm()', since the actual
hardware switch is deferred until return to userspace. At this point, or
if there is a intermediate call to 'uaccess_enable()', the page-table
and ASID of the new process are installed. Sadly, due to the changes
introduced by KPTI, this is not an atomic operation and there is a very
small window (two instructions) where the CPU is configured with the
page-table of the old task and the ASID of the new task; a speculative
access in this state is disastrous because it would corrupt the TLB
entries for the new task with mappings from the previous address space.

As Pavel explains:

| I was able to reproduce memory corruption problem on Broadcom's SoC
| ARMv8-A like this:
|
| Enable software perf-events with PERF_SAMPLE_CALLCHAIN so userland's
| stack is accessed and copied.
|
| The test program performed the following on every CPU and forking
| many processes:
|
| unsigned long *map = mmap(NULL, PAGE_SIZE, PROT_READ|PROT_WRITE,
| MAP_SHARED | MAP_ANONYMOUS, -1, 0);
| map[0] = getpid();
| sched_yield();
| if (map[0] != getpid()) {
| fprintf(stderr, "Corruption detected!");
| }
| munmap(map, PAGE_SIZE);
|
| From time to time I was getting map[0] to contain pid for a
| different process.

Ensure that PAN is re-enabled when returning after an unhandled user
fault from our uaccess routines.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org>
Fixes: 338d4f49d6f7 ("arm64: kernel: Add support for Privileged Access Never")
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
[will: rewrote commit message]
Signed-off-by: Will Deacon <will@kernel.org>

Pull pidfd fixlet from Christian Brauner:
"This contains a simple fix for the pidfd poll method. In the original
patchset pidfd_poll() was made to return an unsigned int. However, the
poll method is defined to return a __poll_t. While the unsigned int is
not a huge deal it's just nicer to return a __poll_t.

I've decided to send it right before the 5.4 release mainly so that
stable doesn't need to backport it to both 5.4 and 5.3"

* tag 'for-linus-2019-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
fork: fix pidfd_poll()'s return type

gpio fixes for v5.4-rc8

- fix debounce times in max776520 and bd70528
- fix parallel build of gpio tools

The driver misses calling destroy_workqueue in remove like what is done
when probe fails.
Add the missed calls to fix it.

Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When the CC variable contains quotes, e.g. when using
ccache (make CC="ccache <compiler>"), this script always
fails, so CONFIG_RELR is never enabled, even when the
toolchain supports this feature. Removing the /dev/null
redirect and invoking the script manually shows the issue:

$ CC='/usr/bin/ccache clang' ./scripts/tools-support-relr.sh
./scripts/tools-support-relr.sh: 7: ./scripts/tools-support-relr.sh: /usr/bin/ccache clang: not found

Fix this by un-quoting the variables.

Before:
$ make ARCH=arm64 CC='/usr/bin/ccache clang' LD=ld.lld \
NM=llvm-nm OBJCOPY=llvm-objcopy defconfig
$ grep RELR .config
CONFIG_ARCH_HAS_RELR=y

With this change:
$ make ARCH=arm64 CC='/usr/bin/ccache clang' LD=ld.lld \
NM=llvm-nm OBJCOPY=llvm-objcopy defconfig
$ grep RELR .config
CONFIG_TOOLS_SUPPORT_RELR=y
CONFIG_ARCH_HAS_RELR=y
CONFIG_RELR=y

Fixes: 5cf896fb6be3 ("arm64: Add support for relocating the kernel with RELR relocations")
Reported-by: Dmitry Golovin <dima@golovin.in>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/769
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
Signed-off-by: Will Deacon <will@kernel.org>

In afs_wait_for_call_to_complete(), rather than immediately aborting an
operation if a signal occurs, the code attempts to wait for it to
complete, using a schedule timeout of 2*RTT (or min 2 jiffies) and a
check that we're still receiving relevant packets from the server before
we consider aborting the call. We may even ping the server to check on
the status of the call.

However, there's a missing timeout reset in the event that we do
actually get a packet to process, such that if we then get a couple of
short stalls, we then time out when progress is actually being made.

Fix this by resetting the timeout any time we get something to process.
If it's the failure of the call then the call state will get changed and
we'll exit the loop shortly thereafter.

A symptom of this is data fetches and stores failing with EINTR when
they really shouldn't.

Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

pidfd_poll() is defined as returning 'unsigned int' but the
.poll method is declared as returning '__poll_t', a bitwise type.

Fix this by using the proper return type and using the EPOLL
constants instead of the POLL ones, as required for __poll_t.

Fixes: b53b0b9d9a61 ("pidfd: add polling support")
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: stable@vger.kernel.org # 5.3
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191120003320.31138-1-luc.vanoostenryck@gmail.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

The Terra Pad 1061 has the usual micro-USB-B id-pin handler, but instead
of controlling the actual micro-USB-B it turns the 5V boost for the
tablet's USB-A connector and its keyboard-cover connector off.

The actual micro-USB-B connector on the tablet is wired for charging only,
and its id pin is *not* connected to the GPIO which is used for the
(broken) id-pin event handler in the DSDT.

While at it not only add a comment why the Terra Pad 1061 is on the
blacklist, but also fix the missing comment for the Minix Neo Z83-4 entry.

Fixes: 61f7f7c8f978 ("gpiolib: acpi: Add gpiolib_acpi_run_edge_events_on_boot option and blacklist")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>