<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch/arm, branch v5.4.178</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>ARM: dts: gpio-ranges property is now required</title>
<updated>2022-01-29T09:25:11+00:00</updated>
<author>
<name>Phil Elwell</name>
<email>phil@raspberrypi.com</email>
</author>
<published>2022-01-25T19:42:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c3fa7ce43cddf8eacf8d0c04e1467d68449547c9'/>
<id>c3fa7ce43cddf8eacf8d0c04e1467d68449547c9</id>
<content type='text'>
commit c8013355ead68dce152cf426686f8a5f80d88b40 upstream

Since [1], added in 5.7, the absence of a gpio-ranges property has
prevented GPIOs from being restored to inputs when released.
Add those properties for BCM283x and BCM2711 devices.

[1] commit 2ab73c6d8323 ("gpio: Support GPIO controllers without
    pin-ranges")

Link: https://lore.kernel.org/r/20220104170247.956760-1-linus.walleij@linaro.org
Fixes: 2ab73c6d8323 ("gpio: Support GPIO controllers without pin-ranges")
Fixes: 266423e60ea1 ("pinctrl: bcm2835: Change init order for gpio hogs")
Reported-by: Stefan Wahren &lt;stefan.wahren@i2se.com&gt;
Reported-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Reported-by: Jan Kiszka &lt;jan.kiszka@web.de&gt;
Signed-off-by: Phil Elwell &lt;phil@raspberrypi.com&gt;
Acked-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Reviewed-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Link: https://lore.kernel.org/r/20211206092237.4105895-3-phil@raspberrypi.com
Signed-off-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Acked-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Signed-off-by: Olof Johansson &lt;olof@lixom.net&gt;
[florian: Remove bcm2711.dtsi hunk which does not exist in 5.4]
Signed-off-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c8013355ead68dce152cf426686f8a5f80d88b40 upstream

Since [1], added in 5.7, the absence of a gpio-ranges property has
prevented GPIOs from being restored to inputs when released.
Add those properties for BCM283x and BCM2711 devices.

[1] commit 2ab73c6d8323 ("gpio: Support GPIO controllers without
    pin-ranges")

Link: https://lore.kernel.org/r/20220104170247.956760-1-linus.walleij@linaro.org
Fixes: 2ab73c6d8323 ("gpio: Support GPIO controllers without pin-ranges")
Fixes: 266423e60ea1 ("pinctrl: bcm2835: Change init order for gpio hogs")
Reported-by: Stefan Wahren &lt;stefan.wahren@i2se.com&gt;
Reported-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Reported-by: Jan Kiszka &lt;jan.kiszka@web.de&gt;
Signed-off-by: Phil Elwell &lt;phil@raspberrypi.com&gt;
Acked-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Reviewed-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Link: https://lore.kernel.org/r/20211206092237.4105895-3-phil@raspberrypi.com
Signed-off-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Acked-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Signed-off-by: Olof Johansson &lt;olof@lixom.net&gt;
[florian: Remove bcm2711.dtsi hunk which does not exist in 5.4]
Signed-off-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: shmobile: rcar-gen2: Add missing of_node_put()</title>
<updated>2022-01-27T08:19:40+00:00</updated>
<author>
<name>Wan Jiabing</name>
<email>wanjiabing@vivo.com</email>
</author>
<published>2021-10-18T01:45:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c93a934f812e38dd319fb9f88c87cdd76d99443b'/>
<id>c93a934f812e38dd319fb9f88c87cdd76d99443b</id>
<content type='text'>
[ Upstream commit 85744f2d938c5f3cfc44cb6533c157469634da93 ]

Fix following coccicheck warning:
./arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c:156:1-33: Function
for_each_matching_node_and_match should have of_node_put() before break
and goto.

Early exits from for_each_matching_node_and_match() should decrement the
node reference counter.

Signed-off-by: Wan Jiabing &lt;wanjiabing@vivo.com&gt;
Link: https://lore.kernel.org/r/20211018014503.7598-1-wanjiabing@vivo.com
Signed-off-by: Geert Uytterhoeven &lt;geert+renesas@glider.be&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 85744f2d938c5f3cfc44cb6533c157469634da93 ]

Fix following coccicheck warning:
./arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c:156:1-33: Function
for_each_matching_node_and_match should have of_node_put() before break
and goto.

Early exits from for_each_matching_node_and_match() should decrement the
node reference counter.

Signed-off-by: Wan Jiabing &lt;wanjiabing@vivo.com&gt;
Link: https://lore.kernel.org/r/20211018014503.7598-1-wanjiabing@vivo.com
Signed-off-by: Geert Uytterhoeven &lt;geert+renesas@glider.be&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: dts: armada-38x: Add generic compatible to UART nodes</title>
<updated>2022-01-27T08:19:34+00:00</updated>
<author>
<name>Marek Behún</name>
<email>kabel@kernel.org</email>
</author>
<published>2021-11-09T16:46:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=db6eb2f94ad7672bfb56372c17d028cf85a165d4'/>
<id>db6eb2f94ad7672bfb56372c17d028cf85a165d4</id>
<content type='text'>
[ Upstream commit 62480772263ab6b52e758f2346c70a526abd1d28 ]

Add generic compatible string "ns16550a" to serial port nodes of Armada
38x.

This makes it possible to use earlycon.

Fixes: 0d3d96ab0059 ("ARM: mvebu: add Device Tree description of the Armada 380/385 SoCs")
Signed-off-by: Pali Rohár &lt;pali@kernel.org&gt;
Signed-off-by: Marek Behún &lt;kabel@kernel.org&gt;
Signed-off-by: Gregory CLEMENT &lt;gregory.clement@bootlin.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 62480772263ab6b52e758f2346c70a526abd1d28 ]

Add generic compatible string "ns16550a" to serial port nodes of Armada
38x.

This makes it possible to use earlycon.

Fixes: 0d3d96ab0059 ("ARM: mvebu: add Device Tree description of the Armada 380/385 SoCs")
Signed-off-by: Pali Rohár &lt;pali@kernel.org&gt;
Signed-off-by: Marek Behún &lt;kabel@kernel.org&gt;
Signed-off-by: Gregory CLEMENT &lt;gregory.clement@bootlin.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 9159/1: decompressor: Avoid UNPREDICTABLE NOP encoding</title>
<updated>2022-01-27T08:19:34+00:00</updated>
<author>
<name>Andre Przywara</name>
<email>andre.przywara@arm.com</email>
</author>
<published>2021-11-22T15:28:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3f8edc28c02b44e8f1f69b226f8035d0e8a28665'/>
<id>3f8edc28c02b44e8f1f69b226f8035d0e8a28665</id>
<content type='text'>
[ Upstream commit a92882a4d270fbcc021ee6848de5e48b7f0d27f3 ]

In the decompressor's head.S we need to start with an instruction that
is some kind of NOP, but also mimics as the PE/COFF header, when the
kernel is linked as an UEFI application. The clever solution here is
"tstne r0, #0x4d000", which in the worst case just clobbers the
condition flags, and bears the magic "MZ" signature in the lowest 16 bits.

However the encoding used (0x13105a4d) is actually not valid, since bits
[15:12] are supposed to be 0 (written as "(0)" in the ARM ARM).
Violating this is UNPREDICTABLE, and *can* trigger an UNDEFINED
exception. Common Cortex cores seem to ignore those bits, but QEMU
chooses to trap, so the code goes fishing because of a missing exception
handler at this point. We are just saved by the fact that commonly (with
-kernel or when running from U-Boot) the "Z" bit is set, so the
instruction is never executed. See [0] for more details.

To make things more robust and avoid UNPREDICTABLE behaviour in the
kernel code, lets replace this with a "two-instruction NOP":
The first instruction is an exclusive OR, the effect of which the second
instruction reverts. This does not leave any trace, neither in a
register nor in the condition flags. Also it's a perfectly valid
encoding. Kudos to Peter Maydell for coming up with this gem.

[0] https://lore.kernel.org/qemu-devel/YTPIdbUCmwagL5%2FD@os.inf.tu-dresden.de/T/

Link: https://lore.kernel.org/linux-arm-kernel/20210908162617.104962-1-andre.przywara@arm.com/T/

Fixes: 81a0bc39ea19 ("ARM: add UEFI stub support")
Signed-off-by: Andre Przywara &lt;andre.przywara@arm.com&gt;
Reported-by: Adam Lackorzynski &lt;adam@l4re.org&gt;
Suggested-by: Peter Maydell &lt;peter.maydell@linaro.org&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Reviewed-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit a92882a4d270fbcc021ee6848de5e48b7f0d27f3 ]

In the decompressor's head.S we need to start with an instruction that
is some kind of NOP, but also mimics as the PE/COFF header, when the
kernel is linked as an UEFI application. The clever solution here is
"tstne r0, #0x4d000", which in the worst case just clobbers the
condition flags, and bears the magic "MZ" signature in the lowest 16 bits.

However the encoding used (0x13105a4d) is actually not valid, since bits
[15:12] are supposed to be 0 (written as "(0)" in the ARM ARM).
Violating this is UNPREDICTABLE, and *can* trigger an UNDEFINED
exception. Common Cortex cores seem to ignore those bits, but QEMU
chooses to trap, so the code goes fishing because of a missing exception
handler at this point. We are just saved by the fact that commonly (with
-kernel or when running from U-Boot) the "Z" bit is set, so the
instruction is never executed. See [0] for more details.

To make things more robust and avoid UNPREDICTABLE behaviour in the
kernel code, lets replace this with a "two-instruction NOP":
The first instruction is an exclusive OR, the effect of which the second
instruction reverts. This does not leave any trace, neither in a
register nor in the condition flags. Also it's a perfectly valid
encoding. Kudos to Peter Maydell for coming up with this gem.

[0] https://lore.kernel.org/qemu-devel/YTPIdbUCmwagL5%2FD@os.inf.tu-dresden.de/T/

Link: https://lore.kernel.org/linux-arm-kernel/20210908162617.104962-1-andre.przywara@arm.com/T/

Fixes: 81a0bc39ea19 ("ARM: add UEFI stub support")
Signed-off-by: Andre Przywara &lt;andre.przywara@arm.com&gt;
Reported-by: Adam Lackorzynski &lt;adam@l4re.org&gt;
Suggested-by: Peter Maydell &lt;peter.maydell@linaro.org&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Reviewed-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: dts: gemini: NAS4220-B: fis-index-block with 128 KiB sectors</title>
<updated>2022-01-27T08:19:33+00:00</updated>
<author>
<name>Christian Lamparter</name>
<email>chunkeey@gmail.com</email>
</author>
<published>2021-12-06T00:43:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b153346f0ffe35317ec9e4126fa21090a69a1498'/>
<id>b153346f0ffe35317ec9e4126fa21090a69a1498</id>
<content type='text'>
[ Upstream commit 4754eab7e5a78bdefe7a960c5c260c95ebbb5fa6 ]

Steven Maddox reported in the OpenWrt bugzilla, that his
RaidSonic IB-NAS4220-B was no longer booting with the new
OpenWrt 21.02 (uses linux 5.10's device-tree). However, it was
working with the previous OpenWrt 19.07 series (uses 4.14).

|[    5.548038] No RedBoot partition table detected in 30000000.flash
|[    5.618553] Searching for RedBoot partition table in 30000000.flash at offset 0x0
|[    5.739093] No RedBoot partition table detected in 30000000.flash
|...
|[    7.039504] Waiting for root device /dev/mtdblock3...

The provided bootlog shows that the RedBoot partition parser was
looking for the partition table "at offset 0x0". Which is strange
since the comment in the device-tree says it should be at 0xfe0000.

Further digging on the internet led to a review site that took
some useful PCB pictures of their review unit back in February 2009.
Their picture shows a Spansion S29GL128N11TFI01 flash chip.

&gt;From Spansion's Datasheet:
"S29GL128N: One hundred twenty-eight 64 Kword (128 Kbyte) sectors"
Steven also provided a "cat /sys/class/mtd/mtd0/erasesize" from his
unit: "131072".

With the 128 KiB Sector/Erasesize in mind. This patch changes the
fis-index-block property to (0xfe0000 / 0x20000) = 0x7f.

Fixes: b5a923f8c739 ("ARM: dts: gemini: Switch to redboot partition parsing")
Reported-by: Steven Maddox &lt;s.maddox@lantizia.me.uk&gt;
Signed-off-by: Christian Lamparter &lt;chunkeey@gmail.com&gt;
Signed-off-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Tested-by: Steven Maddox &lt;s.maddox@lantizia.me.uk&gt;
Link: https://lore.kernel.org/r/20211206004334.4169408-1-linus.walleij@linaro.org'
Bugzilla: https://bugs.openwrt.org/index.php?do=details&amp;task_id=4137
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 4754eab7e5a78bdefe7a960c5c260c95ebbb5fa6 ]

Steven Maddox reported in the OpenWrt bugzilla, that his
RaidSonic IB-NAS4220-B was no longer booting with the new
OpenWrt 21.02 (uses linux 5.10's device-tree). However, it was
working with the previous OpenWrt 19.07 series (uses 4.14).

|[    5.548038] No RedBoot partition table detected in 30000000.flash
|[    5.618553] Searching for RedBoot partition table in 30000000.flash at offset 0x0
|[    5.739093] No RedBoot partition table detected in 30000000.flash
|...
|[    7.039504] Waiting for root device /dev/mtdblock3...

The provided bootlog shows that the RedBoot partition parser was
looking for the partition table "at offset 0x0". Which is strange
since the comment in the device-tree says it should be at 0xfe0000.

Further digging on the internet led to a review site that took
some useful PCB pictures of their review unit back in February 2009.
Their picture shows a Spansion S29GL128N11TFI01 flash chip.

&gt;From Spansion's Datasheet:
"S29GL128N: One hundred twenty-eight 64 Kword (128 Kbyte) sectors"
Steven also provided a "cat /sys/class/mtd/mtd0/erasesize" from his
unit: "131072".

With the 128 KiB Sector/Erasesize in mind. This patch changes the
fis-index-block property to (0xfe0000 / 0x20000) = 0x7f.

Fixes: b5a923f8c739 ("ARM: dts: gemini: Switch to redboot partition parsing")
Reported-by: Steven Maddox &lt;s.maddox@lantizia.me.uk&gt;
Signed-off-by: Christian Lamparter &lt;chunkeey@gmail.com&gt;
Signed-off-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Tested-by: Steven Maddox &lt;s.maddox@lantizia.me.uk&gt;
Link: https://lore.kernel.org/r/20211206004334.4169408-1-linus.walleij@linaro.org'
Bugzilla: https://bugs.openwrt.org/index.php?do=details&amp;task_id=4137
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 9025/1: Kconfig: CPU_BIG_ENDIAN depends on !LD_IS_LLD</title>
<updated>2022-01-20T08:19:19+00:00</updated>
<author>
<name>Nick Desaulniers</name>
<email>ndesaulniers@google.com</email>
</author>
<published>2020-11-16T23:46:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e245aaefef39a6bbd8ce5bb043ede07f4790af77'/>
<id>e245aaefef39a6bbd8ce5bb043ede07f4790af77</id>
<content type='text'>
commit 28187dc8ebd938d574edfc6d9e0f9c51c21ff3f4 upstream.

LLD does not yet support any big endian architectures. Make this config
non-selectable when using LLD until LLD is fixed.

Link: https://github.com/ClangBuiltLinux/linux/issues/965

Signed-off-by: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Tested-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Reviewed-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Reported-by: kbuild test robot &lt;lkp@intel.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Cc: Anders Roxell &lt;anders.roxell@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 28187dc8ebd938d574edfc6d9e0f9c51c21ff3f4 upstream.

LLD does not yet support any big endian architectures. Make this config
non-selectable when using LLD until LLD is fixed.

Link: https://github.com/ClangBuiltLinux/linux/issues/965

Signed-off-by: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Tested-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Reviewed-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Reported-by: kbuild test robot &lt;lkp@intel.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Cc: Anders Roxell &lt;anders.roxell@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf: Protect perf_guest_cbs with RCU</title>
<updated>2022-01-20T08:19:18+00:00</updated>
<author>
<name>Sean Christopherson</name>
<email>seanjc@google.com</email>
</author>
<published>2021-11-11T02:07:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9b45f2007ea32b6511b98491bd224ae3dae1c5a3'/>
<id>9b45f2007ea32b6511b98491bd224ae3dae1c5a3</id>
<content type='text'>
commit ff083a2d972f56bebfd82409ca62e5dfce950961 upstream.

Protect perf_guest_cbs with RCU to fix multiple possible errors.  Luckily,
all paths that read perf_guest_cbs already require RCU protection, e.g. to
protect the callback chains, so only the direct perf_guest_cbs touchpoints
need to be modified.

Bug #1 is a simple lack of WRITE_ONCE/READ_ONCE behavior to ensure
perf_guest_cbs isn't reloaded between a !NULL check and a dereference.
Fixed via the READ_ONCE() in rcu_dereference().

Bug #2 is that on weakly-ordered architectures, updates to the callbacks
themselves are not guaranteed to be visible before the pointer is made
visible to readers.  Fixed by the smp_store_release() in
rcu_assign_pointer() when the new pointer is non-NULL.

Bug #3 is that, because the callbacks are global, it's possible for
readers to run in parallel with an unregisters, and thus a module
implementing the callbacks can be unloaded while readers are in flight,
resulting in a use-after-free.  Fixed by a synchronize_rcu() call when
unregistering callbacks.

Bug #1 escaped notice because it's extremely unlikely a compiler will
reload perf_guest_cbs in this sequence.  perf_guest_cbs does get reloaded
for future derefs, e.g. for -&gt;is_user_mode(), but the -&gt;is_in_guest()
guard all but guarantees the consumer will win the race, e.g. to nullify
perf_guest_cbs, KVM has to completely exit the guest and teardown down
all VMs before KVM start its module unload / unregister sequence.  This
also makes it all but impossible to encounter bug #3.

Bug #2 has not been a problem because all architectures that register
callbacks are strongly ordered and/or have a static set of callbacks.

But with help, unloading kvm_intel can trigger bug #1 e.g. wrapping
perf_guest_cbs with READ_ONCE in perf_misc_flags() while spamming
kvm_intel module load/unload leads to:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] PREEMPT SMP
  CPU: 6 PID: 1825 Comm: stress Not tainted 5.14.0-rc2+ #459
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:perf_misc_flags+0x1c/0x70
  Call Trace:
   perf_prepare_sample+0x53/0x6b0
   perf_event_output_forward+0x67/0x160
   __perf_event_overflow+0x52/0xf0
   handle_pmi_common+0x207/0x300
   intel_pmu_handle_irq+0xcf/0x410
   perf_event_nmi_handler+0x28/0x50
   nmi_handle+0xc7/0x260
   default_do_nmi+0x6b/0x170
   exc_nmi+0x103/0x130
   asm_exc_nmi+0x76/0xbf

Fixes: 39447b386c84 ("perf: Enhance perf to allow for guest statistic collection from host")
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211111020738.2512932-2-seanjc@google.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ff083a2d972f56bebfd82409ca62e5dfce950961 upstream.

Protect perf_guest_cbs with RCU to fix multiple possible errors.  Luckily,
all paths that read perf_guest_cbs already require RCU protection, e.g. to
protect the callback chains, so only the direct perf_guest_cbs touchpoints
need to be modified.

Bug #1 is a simple lack of WRITE_ONCE/READ_ONCE behavior to ensure
perf_guest_cbs isn't reloaded between a !NULL check and a dereference.
Fixed via the READ_ONCE() in rcu_dereference().

Bug #2 is that on weakly-ordered architectures, updates to the callbacks
themselves are not guaranteed to be visible before the pointer is made
visible to readers.  Fixed by the smp_store_release() in
rcu_assign_pointer() when the new pointer is non-NULL.

Bug #3 is that, because the callbacks are global, it's possible for
readers to run in parallel with an unregisters, and thus a module
implementing the callbacks can be unloaded while readers are in flight,
resulting in a use-after-free.  Fixed by a synchronize_rcu() call when
unregistering callbacks.

Bug #1 escaped notice because it's extremely unlikely a compiler will
reload perf_guest_cbs in this sequence.  perf_guest_cbs does get reloaded
for future derefs, e.g. for -&gt;is_user_mode(), but the -&gt;is_in_guest()
guard all but guarantees the consumer will win the race, e.g. to nullify
perf_guest_cbs, KVM has to completely exit the guest and teardown down
all VMs before KVM start its module unload / unregister sequence.  This
also makes it all but impossible to encounter bug #3.

Bug #2 has not been a problem because all architectures that register
callbacks are strongly ordered and/or have a static set of callbacks.

But with help, unloading kvm_intel can trigger bug #1 e.g. wrapping
perf_guest_cbs with READ_ONCE in perf_misc_flags() while spamming
kvm_intel module load/unload leads to:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] PREEMPT SMP
  CPU: 6 PID: 1825 Comm: stress Not tainted 5.14.0-rc2+ #459
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:perf_misc_flags+0x1c/0x70
  Call Trace:
   perf_prepare_sample+0x53/0x6b0
   perf_event_output_forward+0x67/0x160
   __perf_event_overflow+0x52/0xf0
   handle_pmi_common+0x207/0x300
   intel_pmu_handle_irq+0xcf/0x410
   perf_event_nmi_handler+0x28/0x50
   nmi_handle+0xc7/0x260
   default_do_nmi+0x6b/0x170
   exc_nmi+0x103/0x130
   asm_exc_nmi+0x76/0xbf

Fixes: 39447b386c84 ("perf: Enhance perf to allow for guest statistic collection from host")
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211111020738.2512932-2-seanjc@google.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 9169/1: entry: fix Thumb2 bug in iWMMXt exception handling</title>
<updated>2021-12-29T11:23:37+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2021-12-15T08:31:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5478b90270a3569cf6f596959b0900c9f8ef8fe4'/>
<id>5478b90270a3569cf6f596959b0900c9f8ef8fe4</id>
<content type='text'>
commit 8536a5ef886005bc443c2da9b842d69fd3d7647f upstream.

The Thumb2 version of the FP exception handling entry code treats the
register holding the CP number (R8) differently, resulting in the iWMMXT
CP number check to be incorrect.

Fix this by unifying the ARM and Thumb2 code paths, and switch the
order of the additions of the TI_USED_CP offset and the shifted CP
index.

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: b86040a59feb ("Thumb-2: Implementation of the unified start-up and exceptions code")
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8536a5ef886005bc443c2da9b842d69fd3d7647f upstream.

The Thumb2 version of the FP exception handling entry code treats the
register holding the CP number (R8) differently, resulting in the iWMMXT
CP number check to be incorrect.

Fix this by unifying the ARM and Thumb2 code paths, and switch the
order of the additions of the TI_USED_CP offset and the shifted CP
index.

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: b86040a59feb ("Thumb-2: Implementation of the unified start-up and exceptions code")
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: dts: imx6ull-pinfunc: Fix CSI_DATA07__ESAI_TX0 pad name</title>
<updated>2021-12-22T08:29:39+00:00</updated>
<author>
<name>Fabio Estevam</name>
<email>festevam@gmail.com</email>
</author>
<published>2021-11-24T18:45:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=29e9fdf7b681401253427860c334f0c3c132907b'/>
<id>29e9fdf7b681401253427860c334f0c3c132907b</id>
<content type='text'>
commit 737e65c7956795b3553781fb7bc82fce1c39503f upstream.

According to the i.MX6ULL Reference Manual, pad CSI_DATA07 may
have the ESAI_TX0 functionality, not ESAI_T0.

Also, NXP's i.MX Config Tools 10.0 generates dtsi with the
MX6ULL_PAD_CSI_DATA07__ESAI_TX0 naming, so fix it accordingly.

There are no devicetree users in mainline that use the old name,
so just remove the old entry.

Fixes: c201369d4aa5 ("ARM: dts: imx6ull: add imx6ull support")
Reported-by: George Makarov &lt;georgemakarov1@gmail.com&gt;
Signed-off-by: Fabio Estevam &lt;festevam@gmail.com&gt;
Signed-off-by: Shawn Guo &lt;shawnguo@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 737e65c7956795b3553781fb7bc82fce1c39503f upstream.

According to the i.MX6ULL Reference Manual, pad CSI_DATA07 may
have the ESAI_TX0 functionality, not ESAI_T0.

Also, NXP's i.MX Config Tools 10.0 generates dtsi with the
MX6ULL_PAD_CSI_DATA07__ESAI_TX0 naming, so fix it accordingly.

There are no devicetree users in mainline that use the old name,
so just remove the old entry.

Fixes: c201369d4aa5 ("ARM: dts: imx6ull: add imx6ull support")
Reported-by: George Makarov &lt;georgemakarov1@gmail.com&gt;
Signed-off-by: Fabio Estevam &lt;festevam@gmail.com&gt;
Signed-off-by: Shawn Guo &lt;shawnguo@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: socfpga: dts: fix qspi node compatible</title>
<updated>2021-12-22T08:29:35+00:00</updated>
<author>
<name>Dinh Nguyen</name>
<email>dinguyen@kernel.org</email>
</author>
<published>2021-11-02T00:36:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f83ed203c822ee5c9e30a31c387714503d6603b3'/>
<id>f83ed203c822ee5c9e30a31c387714503d6603b3</id>
<content type='text'>
[ Upstream commit cb25b11943cbcc5a34531129952870420f8be858 ]

The QSPI flash node needs to have the required "jedec,spi-nor" in the
compatible string.

Fixes: 1df99da8953 ("ARM: dts: socfpga: Enable QSPI in Arria10 devkit")
Signed-off-by: Dinh Nguyen &lt;dinguyen@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit cb25b11943cbcc5a34531129952870420f8be858 ]

The QSPI flash node needs to have the required "jedec,spi-nor" in the
compatible string.

Fixes: 1df99da8953 ("ARM: dts: socfpga: Enable QSPI in Arria10 devkit")
Signed-off-by: Dinh Nguyen &lt;dinguyen@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
