Merge tag 'visconti-arm-defconfig-for-v5.14' of https://git.kernel.org/pub/scm/linux/kernel/git/iwamatsu/linux-visconti into arm/defconfig

Visconti defconfig updates for v5.14

- Enable Visconti's PWM in the ARM64 defconfig as a module.
- Enable Visconti's GPIO in the ARM64 defconfig.

* tag 'visconti-arm-defconfig-for-v5.14' of https://git.kernel.org/pub/scm/linux/kernel/git/iwamatsu/linux-visconti:
  arm64: defconfig: Visconti: Enable GPIO
  arm64: defconfig: Visconti: Enable PWM

Link: https://lore.kernel.org/r/20210615231232.pllzlqoamkmnsqq6@toshiba.co.jpSigned-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'tegra-for-5.14-arm-defconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into arm/defconfig

ARM: tegra: Default configuration changes for v5.14-rc1

Enables the devfreq thermal support to allow using the devfreq device as
cooling device for the system.

* tag 'tegra-for-5.14-arm-defconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux:
  ARM: tegra_defconfig: Enable CONFIG_DEVFREQ_THERMAL

Link: https://lore.kernel.org/r/20210611164437.3568059-5-thierry.reding@gmail.comSigned-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'qcom-arm64-defconfig-for-5.14' of https://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux into arm/defconfig

Qualcomm ARM64 defconfig udpates for v5.14

This enables VADC, audio codecs and Venus (video decoder) found on
MSM8916 among others and the SM8350 interconnect provider driver.

* tag 'qcom-arm64-defconfig-for-5.14' of https://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux:
  arm64: defconfig: add drivers needed for DragonBoard410c
  arm64: defconfig: qcom: enable interconnect for SM8350

Link: https://lore.kernel.org/r/20210614223704.393042-1-bjorn.andersson@linaro.orgSigned-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'samsung-defconfig-5.14' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux into arm/defconfig

Samsung defconfig changes for v5.14

1. Enable Exynos Universal Flash Storage (UFS) driver for Exynos7 arm64
   boards.
2. Restore framebuffer support in exynos_defconfig.

* tag 'samsung-defconfig-5.14' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux:
  ARM: exynos_defconfig: restore framebuffer support
  arm64: defconfig: Enable Exynos UFS driver

Link: https://lore.kernel.org/r/20210614193309.20248-3-krzysztof.kozlowski@canonical.comSigned-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'imx-defconfig-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux into arm/defconfig

i.MX defconfig update for 5.14:

- Enable LT8912B DRM bridge and Layerscape EDAC driver support in arm64
  defconfig.
- Enable WiFi ath10k SDIO driver in imx_v6_v7_defconfig.

* tag 'imx-defconfig-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
  ARM: imx_v6_v7_defconfig: Select the Wifi ath10k sdio driver
  arm64: defconfig: enable Layerscape EDAC driver
  arm64: defconfig: Enable LT8912B DRM bridge driver

Link: https://lore.kernel.org/r/20210613082544.16067-6-shawnguo@kernel.orgSigned-off-by: Olof Johansson <olof@lixom.net>

Enable Visconti's GPIO in the ARM64 defconfig.
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>

Enable Visconti's PWM in the ARM64 defconfig as a module.
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>

Add modules with drivers needed for DragonBoard410c board
(arch/arm64/boot/dts/qcom/apq8016-sbc.dts).
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20210528140625.6972-1-m.szyprowski@samsung.comSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Merge tag 'at91-defconfig-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux into arm/defconfig

AT91 defconfig for 5.14:

- Add the use of tickless and HR times to ARM9 defconfig

* tag 'at91-defconfig-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux:
  ARM: configs: at91_dt_defconfig: configs for sam9x60

Link: https://lore.kernel.org/r/20210611125659.25590-1-nicolas.ferre@microchip.comSigned-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'v5.13-next-defconfig' of https://git.kernel.org/pub/scm/linux/kernel/git/matthias.bgg/linux into arm/defconfig

- Delete MTK_PMIC_WRAP added twice.
- Set MMC_MTK as built-in to be able to boot from MMC device.

* tag 'v5.13-next-defconfig' of https://git.kernel.org/pub/scm/linux/kernel/git/matthias.bgg/linux:
  arm64: defconfig: Allow Mediatek boards to boot from the mmc
  arm64: defconfig: Do not override the MTK_PMIC_WRAP symbol

Link: https://lore.kernel.org/r/ad6f7f4e-7e4d-08b9-8781-71bd78444929@gmail.comSigned-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'renesas-arm-defconfig-for-v5.14-tag2' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-devel into arm/defconfig

Renesas ARM defconfig updates for v5.14 (take two)

  - Enable support for the new RZ/G2L SoC variants in the arm64
    defconfig.

* tag 'renesas-arm-defconfig-for-v5.14-tag2' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-devel:
  arm64: defconfig: Enable ARCH_R9A07G044

Link: https://lore.kernel.org/r/cover.1623403795.git.geert+renesas@glider.beSigned-off-by: Olof Johansson <olof@lixom.net>

DEBUG_FS was lost way back in v5.5, and EXT4 is used by ast2600 systems
that have MMC.

Link: https://lore.kernel.org/r/20210610045338.99847-1-joel@jms.id.au
Fixes: 0e4a459f ("tracing: Remove unnecessary DEBUG_FS dependency")
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20210603040906.125109-1-joel@jms.id.auSigned-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'omap-for-v5.14/defconfig-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into arm/defconfig

Defconfig changes for omaps for v5.14 merge window

Defconfig changes for omap2plus_defconfig to add WL1251
and LP5523 as loadable modules for n900.

* tag 'omap-for-v5.14/defconfig-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
  ARM: omap2plus_defconfig: Add LP5523 LED driver
  ARM: omap2plus_defconfig: Add WL1251 and WEXT modules

Link: https://lore.kernel.org/r/pull-1622618286-677305@atomide.com-2Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'renesas-arm-defconfig-for-v5.14-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-devel into arm/defconfig

Renesas ARM defconfig updates for v5.14

  - Refresh shmobile_defconfig for v5.13-rc1
  - Enable R-Car USB2 clock selector support

* tag 'renesas-arm-defconfig-for-v5.14-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-devel:
  arm64: defconfig: Enable usb2_clksel for R-Car Gen3 and RZ/G2
  ARM: shmobile: defconfig: Refresh for v5.13-rc1

Link: https://lore.kernel.org/r/cover.1622188834.git.geert+renesas@glider.beSigned-off-by: Olof Johansson <olof@lixom.net>

Without MTD_PHYSMAP/MTD_PHYSMAP_OF the flash partitions of my welltech,epbx100
are not detected.

Link: https://lore.kernel.org/r/20210504193457.4008384-3-clabbe@baylibre.comSigned-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

My ixp42x-welltech-epbx100 does not print anything on console without
CONFIG_SERIAL_OF_PLATFORM.

Link: https://lore.kernel.org/r/20210504193457.4008384-2-clabbe@baylibre.comSigned-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

Select the ath10k sdio driver so that Wifi can work by default on
boards like imx6dl-pico-pi with a QCA9377 chip.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Commit f611b1e7 ("drm: Avoid circular dependencies for CONFIG_FB")
changed the Kconfig dependencies, so COFNIG_FB is no longer selected in
defconfigs. Restore support for it in exynos_defconfig, because most
Exynos platforms had graphical console running on framebuffer device
emulated on the Exynos DRM drivers.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20210611100204.6240-1-m.szyprowski@samsung.comSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

Enable the Renesas RZ/G2L SoC variants in the ARM64 defconfig.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20210609153230.6967-6-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Enable CONFIG_NO_HZ_IDLE and CONFIG_HIGH_RES_TIMERS=y to be used
in conjunction with PIT64B present on SAM9X60.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20210406141152.10706-1-claudiu.beznea@microchip.com

Enable the Exynos UFS controller and PHY configs. They need to be
buildin to ensure UFS devices gets detected on exynos7 and its
variant boards.
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Link: https://lore.kernel.org/r/20210531170057.7730-1-alim.akhtar@samsung.comSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

Enable the interconnect for SM8350 as a module
Reviewed-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20210510070725.3839459-1-vkoul@kernel.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Memory-related Tegra devfreq devices now could be used as a cooling
devices. Enable CONFIG_DEVFREQ_THERMAL by default since this option
enables cooling functionality of the devfreq drivers.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

There is a clock driver that's needed when using an external
USB reference clock called usb2_clksel.
Enable it in the defconfig.
Signed-off-by: Adam Ford <aford173@gmail.com>
Link: https://lore.kernel.org/r/20210513114617.30191-3-aford173@gmail.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Pull perf fixes from Thomas Gleixner:
 "Two perf fixes:

   - Do not check the LBR_TOS MSR when setting up unrelated LBR MSRs as
     this can cause malfunction when TOS is not supported

   - Allocate the LBR XSAVE buffers along with the DS buffers upfront
     because allocating them when adding an event can deadlock"

* tag 'perf-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/lbr: Remove cpuc->lbr_xsave allocation from atomic context
  perf/x86: Avoid touching LBR_TOS MSR for Arch LBR

Pull locking fixes from Thomas Gleixner:
 "Two locking fixes:

   - Invoke the lockdep tracepoints in the correct place so the ordering
     is correct again

   - Don't leave the mutex WAITER bit stale when the last waiter is
     dropping out early due to a signal as that forces all subsequent
     lock operations needlessly into the slowpath until it's cleaned up
     again"

* tag 'locking-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/mutex: clear MUTEX_FLAGS if wait_list is empty due to signal
  locking/lockdep: Correct calling tracepoints

Pull irq fixes from Thomas Gleixner:
 "A few fixes for irqchip drivers:

   - Allocate interrupt descriptors correctly on Mainstone PXA when
     SPARSE_IRQ is enabled; otherwise the interrupt association fails

   - Make the APPLE AIC chip driver depend on APPLE

   - Remove redundant error output on devm_ioremap_resource() failure"

* tag 'irq-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip: Remove redundant error printing
  irqchip/apple-aic: APPLE_AIC should depend on ARCH_APPLE
  ARM: PXA: Fix cplds irqdesc allocation when using legacy mode

Pull x86 fixes from Borislav Petkov:

 - Fix how SEV handles MMIO accesses by forwarding potential page faults
   instead of killing the machine and by using the accessors with the
   exact functionality needed when accessing memory.

 - Fix a confusion with Clang LTO compiler switches passed to the it

 - Handle the case gracefully when VMGEXIT has been executed in
   userspace

* tag 'x86_urgent_for_v5.13_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sev-es: Use __put_user()/__get_user() for data accesses
  x86/sev-es: Forward page-faults which happen during emulation
  x86/sev-es: Don't return NULL from sev_es_get_ghcb()
  x86/build: Fix location of '-plugin-opt=' flags
  x86/sev-es: Invalidate the GHCB after completing VMGEXIT
  x86/sev-es: Move sev_es_put_ghcb() in prep for follow on patch

Pull powerpc fixes from Michael Ellerman:

 - Fix breakage of strace (and other ptracers etc.) when using the new
   scv ABI (Power9 or later with glibc >= 2.33).

 - Fix early_ioremap() on 64-bit, which broke booting on some machines.

Thanks to Dmitry V. Levin, Nicholas Piggin, Alexey Kardashevskiy, and
Christophe Leroy.

* tag 'powerpc-5.13-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s/syscall: Fix ptrace syscall info with scv syscalls
  powerpc/64s/syscall: Use pt_regs.trap to distinguish syscall ABI difference between sc and scv syscalls
  powerpc: Fix early setup to make early_ioremap() work

Merge tag 'kbuild-fixes-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Fix short log indentation for tools builds

 - Fix dummy-tools to adjust to the latest stackprotector check

* tag 'kbuild-fixes-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: dummy-tools: adjust to stricter stackprotector check
  scripts/jobserver-exec: Fix a typo ("envirnoment")
  tools build: Fix quiet cmd indentation

Merge misc fixes from Andrew Morton:
 "10 patches.

  Subsystems affected by this patch series: mm (pagealloc, gup, kasan,
  and userfaultfd), ipc, selftests, watchdog, bitmap, procfs, and lib"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  userfaultfd: hugetlbfs: fix new flag usage in error path
  lib: kunit: suppress a compilation warning of frame size
  proc: remove Alexey from MAINTAINERS
  linux/bits.h: fix compilation error with GENMASK
  watchdog: reliable handling of timestamps
  kasan: slab: always reset the tag in get_freepointer_safe()
  tools/testing/selftests/exec: fix link error
  ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry
  Revert "mm/gup: check page posion status for coredump."
  mm/shuffle: fix section mismatch warning

In commit d6995da3 ("hugetlb: use page.private for hugetlb specific
page flags") the use of PagePrivate to indicate a reservation count
should be restored at free time was changed to the hugetlb specific flag
HPageRestoreReserve.  Changes to a userfaultfd error path as well as a
VM_BUG_ON() in remove_inode_hugepages() were overlooked.

Users could see incorrect hugetlb reserve counts if they experience an
error with a UFFDIO_COPY operation.  Specifically, this would be the
result of an unlikely copy_huge_page_from_user error.  There is not an
increased chance of hitting the VM_BUG_ON.

Link: https://lkml.kernel.org/r/20210521233952.236434-1-mike.kravetz@oracle.com
Fixes: d6995da3 ("hugetlb: use page.private for hugetlb specific page flags")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mina Almasry <almasry.mina@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitfield_kunit.c: In function `test_bitfields_constants':
lib/bitfield_kunit.c:93:1: warning: the frame size of 7456 bytes is larger than 2048 bytes [-Wframe-larger-than=]
 }
 ^

As the description of BITFIELD_KUNIT in lib/Kconfig.debug, it "Only useful
for kernel devs running the KUnit test harness, and not intended for
inclusion into a production build".  Therefore, it is not worth modifying
variable 'test_bitfields_constants' to clear this warning.  Just suppress
it.

Link: https://lkml.kernel.org/r/20210518094533.7652-1-thunder.leizhen@huawei.comSigned-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Vitor Massaru Iha <vitor@massaru.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

People Cc me and I don't have time.

Link: https://lkml.kernel.org/r/YKarMxHJBIhMHQIh@localhost.localdomainSigned-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

GENMASK() has an input check which uses __builtin_choose_expr() to
enable a compile time sanity check of its inputs if they are known at
compile time.

However, it turns out that __builtin_constant_p() does not always return
a compile time constant [0].  It was thought this problem was fixed with
gcc 4.9 [1], but apparently this is not the case [2].

Switch to use __is_constexpr() instead which always returns a compile time
constant, regardless of its inputs.

Link: https://lore.kernel.org/lkml/42b4342b-aefc-a16a-0d43-9f9c0d63ba7a@rasmusvillemoes.dk [0]
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19449 [1]
Link: https://lore.kernel.org/lkml/1ac7bbc2-45d9-26ed-0b33-bf382b8d858b@I-love.SAKURA.ne.jp [2]
Link: https://lkml.kernel.org/r/20210511203716.117010-1-rikard.falkeborn@gmail.comSigned-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 9bf3bc94 ("watchdog: cleanup handling of false positives")
tried to handle a virtual host stopped by the host a more
straightforward and cleaner way.

But it introduced a risk of false softlockup reports.  The virtual host
might be stopped at any time, for example between
kvm_check_and_clear_guest_paused() and is_softlockup().  As a result,
is_softlockup() might read the updated jiffies and detects a softlockup.

A solution might be to put back kvm_check_and_clear_guest_paused() after
is_softlockup() and detect it.  But it would put back the cycle that
complicates the logic.

In fact, the handling of all the timestamps is not reliable.  The code
does not guarantee when and how many times the timestamps are read.  For
example, "period_ts" might be touched anytime also from NMI and re-read in
is_softlockup().  It works just by chance.

Fix all the problems by making the code even more explicit.

1. Make sure that "now" and "period_ts" timestamps are read only once.
   They might be changed at anytime by NMI or when the virtual guest is
   stopped by the host.  Note that "now" timestamp does this implicitly
   because "jiffies" is marked volatile.

2. "now" time must be read first.  The state of "period_ts" will
   decide whether it will be used or the period will get restarted.

3. kvm_check_and_clear_guest_paused() must be called before reading
   "period_ts".  It touches the variable when the guest was stopped.

As a result, "now" timestamp is used only when the watchdog was not
touched and the guest not stopped in the meantime.  "period_ts" is
restarted in all other situations.

Link: https://lkml.kernel.org/r/YKT55gw+RZfyoFf7@alley
Fixes: 9bf3bc94 ("watchdog: cleanup handling of false positives")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reported-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

With CONFIG_DEBUG_PAGEALLOC enabled, the kernel should also untag the
object pointer, as done in get_freepointer().

Failing to do so reportedly leads to SLUB freelist corruptions that
manifest as boot-time crashes.

Link: https://lkml.kernel.org/r/20210514072228.534418-1-glider@google.comSigned-off-by: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Elliot Berman <eberman@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix the link error by adding '-static':

  gcc -Wall  -Wl,-z,max-page-size=0x1000 -pie load_address.c -o /home/yang/linux/tools/testing/selftests/exec/load_address_4096
  /usr/bin/ld: /tmp/ccopEGun.o: relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `stderr@@GLIBC_2.17' which may bind externally can not be used when making a shared object; recompile with -fPIC
  /usr/bin/ld: /tmp/ccopEGun.o(.text+0x158): unresolvable R_AARCH64_ADR_PREL_PG_HI21 relocation against symbol `stderr@@GLIBC_2.17'
  /usr/bin/ld: final link failed: bad value
  collect2: error: ld returned 1 exit status
  make: *** [Makefile:25: tools/testing/selftests/exec/load_address_4096] Error 1

Link: https://lkml.kernel.org/r/20210514092422.2367367-1-yangyingliang@huawei.com
Fixes: 206e22f0 ("tools/testing/selftests: add self-test for verifying load alignment")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Cc: Chris Kennelly <ckennelly@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

do_mq_timedreceive calls wq_sleep with a stack local address.  The
sender (do_mq_timedsend) uses this address to later call pipelined_send.

This leads to a very hard to trigger race where a do_mq_timedreceive
call might return and leave do_mq_timedsend to rely on an invalid
address, causing the following crash:

  RIP: 0010:wake_q_add_safe+0x13/0x60
  Call Trace:
   __x64_sys_mq_timedsend+0x2a9/0x490
   do_syscall_64+0x80/0x680
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f5928e40343

The race occurs as:

1. do_mq_timedreceive calls wq_sleep with the address of `struct
   ext_wait_queue` on function stack (aliased as `ewq_addr` here) - it
   holds a valid `struct ext_wait_queue *` as long as the stack has not
   been overwritten.

2. `ewq_addr` gets added to info->e_wait_q[RECV].list in wq_add, and
   do_mq_timedsend receives it via wq_get_first_waiter(info, RECV) to call
   __pipelined_op.

3. Sender calls __pipelined_op::smp_store_release(&this->state,
   STATE_READY).  Here is where the race window begins.  (`this` is
   `ewq_addr`.)

4. If the receiver wakes up now in do_mq_timedreceive::wq_sleep, it
   will see `state == STATE_READY` and break.

5. do_mq_timedreceive returns, and `ewq_addr` is no longer guaranteed
   to be a `struct ext_wait_queue *` since it was on do_mq_timedreceive's
   stack.  (Although the address may not get overwritten until another
   function happens to touch it, which means it can persist around for an
   indefinite time.)

6. do_mq_timedsend::__pipelined_op() still believes `ewq_addr` is a
   `struct ext_wait_queue *`, and uses it to find a task_struct to pass to
   the wake_q_add_safe call.  In the lucky case where nothing has
   overwritten `ewq_addr` yet, `ewq_addr->task` is the right task_struct.
   In the unlucky case, __pipelined_op::wake_q_add_safe gets handed a
   bogus address as the receiver's task_struct causing the crash.

do_mq_timedsend::__pipelined_op() should not dereference `this` after
setting STATE_READY, as the receiver counterpart is now free to return.
Change __pipelined_op to call wake_q_add_safe on the receiver's
task_struct returned by get_task_struct, instead of dereferencing `this`
which sits on the receiver's stack.

As Manfred pointed out, the race potentially also exists in
ipc/msg.c::expunge_all and ipc/sem.c::wake_up_sem_queue_prepare.  Fix
those in the same way.

Link: https://lkml.kernel.org/r/20210510102950.12551-1-varad.gautam@suse.com
Fixes: c5b2cbdb ("ipc/mqueue.c: update/document memory barriers")
Fixes: 8116b54e ("ipc/sem.c: document and update memory barriers")
Fixes: 0d97a82b ("ipc/msg.c: update and document memory barriers")
Signed-off-by: Varad Gautam <varad.gautam@suse.com>
Reported-by: Matthias von Faber <matthias.vonfaber@aox-tech.de>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>