<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch/arm, branch v3.18.86</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>ARM: 8721/1: mm: dump: check hardware RO bit for LPAE</title>
<updated>2017-11-30T08:35:49+00:00</updated>
<author>
<name>Philip Derrin</name>
<email>philip@cog.systems</email>
</author>
<published>2017-11-13T23:55:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f4f6d52542aafca8aec688490ff9aadc8ad53d39'/>
<id>f4f6d52542aafca8aec688490ff9aadc8ad53d39</id>
<content type='text'>
commit 3b0c0c922ff4be275a8beb87ce5657d16f355b54 upstream.

When CONFIG_ARM_LPAE is set, the PMD dump relies on the software
read-only bit to determine whether a page is writable. This
concealed a bug which left the kernel text section writable
(AP2=0) while marked read-only in the software bit.

In a kernel with the AP2 bug, the dump looks like this:

    ---[ Kernel Mapping ]---
    0xc0000000-0xc0200000           2M RW NX SHD
    0xc0200000-0xc0600000           4M ro x  SHD
    0xc0600000-0xc0800000           2M ro NX SHD
    0xc0800000-0xc4800000          64M RW NX SHD

The fix is to check that the software and hardware bits are both
set before displaying "ro". The dump then shows the true perms:

    ---[ Kernel Mapping ]---
    0xc0000000-0xc0200000           2M RW NX SHD
    0xc0200000-0xc0600000           4M RW x  SHD
    0xc0600000-0xc0800000           2M RW NX SHD
    0xc0800000-0xc4800000          64M RW NX SHD

Fixes: ded947798469 ("ARM: 8109/1: mm: Modify pte_write and pmd_write logic for LPAE")
Signed-off-by: Philip Derrin &lt;philip@cog.systems&gt;
Tested-by: Neil Dick &lt;neil@cog.systems&gt;
Reviewed-by: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Russell King &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 3b0c0c922ff4be275a8beb87ce5657d16f355b54 upstream.

When CONFIG_ARM_LPAE is set, the PMD dump relies on the software
read-only bit to determine whether a page is writable. This
concealed a bug which left the kernel text section writable
(AP2=0) while marked read-only in the software bit.

In a kernel with the AP2 bug, the dump looks like this:

    ---[ Kernel Mapping ]---
    0xc0000000-0xc0200000           2M RW NX SHD
    0xc0200000-0xc0600000           4M ro x  SHD
    0xc0600000-0xc0800000           2M ro NX SHD
    0xc0800000-0xc4800000          64M RW NX SHD

The fix is to check that the software and hardware bits are both
set before displaying "ro". The dump then shows the true perms:

    ---[ Kernel Mapping ]---
    0xc0000000-0xc0200000           2M RW NX SHD
    0xc0200000-0xc0600000           4M RW x  SHD
    0xc0600000-0xc0800000           2M RW NX SHD
    0xc0800000-0xc4800000          64M RW NX SHD

Fixes: ded947798469 ("ARM: 8109/1: mm: Modify pte_write and pmd_write logic for LPAE")
Signed-off-by: Philip Derrin &lt;philip@cog.systems&gt;
Tested-by: Neil Dick &lt;neil@cog.systems&gt;
Reviewed-by: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Russell King &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: OMAP2+: Fix init for multiple quirks for the same SoC</title>
<updated>2017-11-21T08:01:04+00:00</updated>
<author>
<name>Tony Lindgren</name>
<email>tony@atomide.com</email>
</author>
<published>2017-01-05T19:08:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=daa36dd42767665901d126d1586a517c003ba528'/>
<id>daa36dd42767665901d126d1586a517c003ba528</id>
<content type='text'>
[ Upstream commit 6e613ebf4405fc09e2a8c16ed193b47f80a3cbed ]

It's possible that there are multiple quirks that need to be initialized
for the same SoC. Fix the issue by not returning on the first match.

Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.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>
[ Upstream commit 6e613ebf4405fc09e2a8c16ed193b47f80a3cbed ]

It's possible that there are multiple quirks that need to be initialized
for the same SoC. Fix the issue by not returning on the first match.

Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "ARM: dts: imx53-qsb-common: fix FEC pinmux config"</title>
<updated>2017-11-18T10:06:30+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2017-11-16T13:29:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=84ea7fc42294c7bbc4f6dc9ee7aa57366c9cf0c7'/>
<id>84ea7fc42294c7bbc4f6dc9ee7aa57366c9cf0c7</id>
<content type='text'>
This reverts commit 2eb85ef18c6570e8a59643cd8d5a66122461b1fc which is
commit 8b649e426336d7d4800ff9c82858328f4215ba01 upstream.

Turns out not to be a good idea in the stable kernels for now as Patrick
writes:
	As discussed for 4.4 stable queue this patch might break
	existing machines, if they use a different pinmux configuration
	with their own bootloader.

Reported-by: Patrick Brünn &lt;P.Bruenn@beckhoff.com&gt;
Cc: Shawn Guo &lt;shawnguo@kernel.org&gt;
Cc: Sasha Levin &lt;alexander.levin@verizon.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>
This reverts commit 2eb85ef18c6570e8a59643cd8d5a66122461b1fc which is
commit 8b649e426336d7d4800ff9c82858328f4215ba01 upstream.

Turns out not to be a good idea in the stable kernels for now as Patrick
writes:
	As discussed for 4.4 stable queue this patch might break
	existing machines, if they use a different pinmux configuration
	with their own bootloader.

Reported-by: Patrick Brünn &lt;P.Bruenn@beckhoff.com&gt;
Cc: Shawn Guo &lt;shawnguo@kernel.org&gt;
Cc: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 8720/1: ensure dump_instr() checks addr_limit</title>
<updated>2017-11-15T09:04:13+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2017-11-02T17:44:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1530d28a893e621c079af741a724cec5ec9e9d93'/>
<id>1530d28a893e621c079af741a724cec5ec9e9d93</id>
<content type='text'>
commit b9dd05c7002ee0ca8b676428b2268c26399b5e31 upstream.

When CONFIG_DEBUG_USER is enabled, it's possible for a user to
deliberately trigger dump_instr() with a chosen kernel address.

Let's avoid problems resulting from this by using get_user() rather than
__get_user(), ensuring that we don't erroneously access kernel memory.

So that we can use the same code to dump user instructions and kernel
instructions, the common dumping code is factored out to __dump_instr(),
with the fs manipulated appropriately in dump_instr() around calls to
this.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Russell King &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 b9dd05c7002ee0ca8b676428b2268c26399b5e31 upstream.

When CONFIG_DEBUG_USER is enabled, it's possible for a user to
deliberately trigger dump_instr() with a chosen kernel address.

Let's avoid problems resulting from this by using get_user() rather than
__get_user(), ensuring that we don't erroneously access kernel memory.

So that we can use the same code to dump user instructions and kernel
instructions, the common dumping code is factored out to __dump_instr(),
with the fs manipulated appropriately in dump_instr() around calls to
this.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Russell King &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: omap2plus_defconfig: Fix probe errors on UARTs 5 and 6</title>
<updated>2017-11-15T09:04:11+00:00</updated>
<author>
<name>Tony Lindgren</name>
<email>tony@atomide.com</email>
</author>
<published>2017-01-20T20:13:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2c2a08631aea3ad623b741798dd39b4cb17b0065'/>
<id>2c2a08631aea3ad623b741798dd39b4cb17b0065</id>
<content type='text'>
[ Upstream commit 4cd6a59f5c1a9b0cca0da09fbba42b9450ffc899 ]

We have more than four uarts on some SoCs and that can cause
noise with errors while booting.

Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.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>
[ Upstream commit 4cd6a59f5c1a9b0cca0da09fbba42b9450ffc899 ]

We have more than four uarts on some SoCs and that can cause
noise with errors while booting.

Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: dts: imx53-qsb-common: fix FEC pinmux config</title>
<updated>2017-11-15T09:04:11+00:00</updated>
<author>
<name>Patrick Bruenn</name>
<email>p.bruenn@beckhoff.com</email>
</author>
<published>2017-01-25T05:25:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2eb85ef18c6570e8a59643cd8d5a66122461b1fc'/>
<id>2eb85ef18c6570e8a59643cd8d5a66122461b1fc</id>
<content type='text'>
[ Upstream commit 8b649e426336d7d4800ff9c82858328f4215ba01 ]

The pinmux configuration in device tree was different from manual
muxing in &lt;u-boot&gt;/board/freescale/mx53loco/mx53loco.c
All pins were configured as NO_PAD_CTL(1 &lt;&lt; 31), which was fine as the
bootloader already did the correct pinmuxing for us.
But recently u-boot is migrating to reuse device tree files from the
kernel tree, so it seems to be better to have the correct pinmuxing in
our files, too.

Signed-off-by: Patrick Bruenn &lt;p.bruenn@beckhoff.com&gt;
Signed-off-by: Shawn Guo &lt;shawnguo@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.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>
[ Upstream commit 8b649e426336d7d4800ff9c82858328f4215ba01 ]

The pinmux configuration in device tree was different from manual
muxing in &lt;u-boot&gt;/board/freescale/mx53loco/mx53loco.c
All pins were configured as NO_PAD_CTL(1 &lt;&lt; 31), which was fine as the
bootloader already did the correct pinmuxing for us.
But recently u-boot is migrating to reuse device tree files from the
kernel tree, so it seems to be better to have the correct pinmuxing in
our files, too.

Signed-off-by: Patrick Bruenn &lt;p.bruenn@beckhoff.com&gt;
Signed-off-by: Shawn Guo &lt;shawnguo@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 8715/1: add a private asm/unaligned.h</title>
<updated>2017-11-08T09:03:48+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2017-10-20T20:17:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e03cbe4026a460ed3d9c4b1d05ad5aaf3d367c38'/>
<id>e03cbe4026a460ed3d9c4b1d05ad5aaf3d367c38</id>
<content type='text'>
commit 1cce91dfc8f7990ca3aea896bfb148f240b12860 upstream.

The asm-generic/unaligned.h header provides two different implementations
for accessing unaligned variables: the access_ok.h version used when
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set pretends that all pointers
are in fact aligned, while the le_struct.h version convinces gcc that the
alignment of a pointer is '1', to make it issue the correct load/store
instructions depending on the architecture flags.

On ARMv5 and older, we always use the second version, to let the compiler
use byte accesses. On ARMv6 and newer, we currently use the access_ok.h
version, so the compiler can use any instruction including stm/ldm and
ldrd/strd that will cause an alignment trap. This trap can significantly
impact performance when we have to do a lot of fixups and, worse, has
led to crashes in the LZ4 decompressor code that does not have a trap
handler.

This adds an ARM specific version of asm/unaligned.h that uses the
le_struct.h/be_struct.h implementation unconditionally. This should lead
to essentially the same code on ARMv6+ as before, with the exception of
using regular load/store instructions instead of the trapping instructions
multi-register variants.

The crash in the LZ4 decompressor code was probably introduced by the
patch replacing the LZ4 implementation, commit 4e1a33b105dd ("lib: update
LZ4 compressor module"), so linux-4.11 and higher would be affected most.
However, we probably want to have this backported to all older stable
kernels as well, to help with the performance issues.

There are two follow-ups that I think we should also work on, but not
backport to stable kernels, first to change the asm-generic version of
the header to remove the ARM special case, and second to review all
other uses of CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS to see if they
might be affected by the same problem on ARM.

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Russell King &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 1cce91dfc8f7990ca3aea896bfb148f240b12860 upstream.

The asm-generic/unaligned.h header provides two different implementations
for accessing unaligned variables: the access_ok.h version used when
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set pretends that all pointers
are in fact aligned, while the le_struct.h version convinces gcc that the
alignment of a pointer is '1', to make it issue the correct load/store
instructions depending on the architecture flags.

On ARMv5 and older, we always use the second version, to let the compiler
use byte accesses. On ARMv6 and newer, we currently use the access_ok.h
version, so the compiler can use any instruction including stm/ldm and
ldrd/strd that will cause an alignment trap. This trap can significantly
impact performance when we have to do a lot of fixups and, worse, has
led to crashes in the LZ4 decompressor code that does not have a trap
handler.

This adds an ARM specific version of asm/unaligned.h that uses the
le_struct.h/be_struct.h implementation unconditionally. This should lead
to essentially the same code on ARMv6+ as before, with the exception of
using regular load/store instructions instead of the trapping instructions
multi-register variants.

The crash in the LZ4 decompressor code was probably introduced by the
patch replacing the LZ4 implementation, commit 4e1a33b105dd ("lib: update
LZ4 compressor module"), so linux-4.11 and higher would be affected most.
However, we probably want to have this backported to all older stable
kernels as well, to help with the performance issues.

There are two follow-ups that I think we should also work on, but not
backport to stable kernels, first to change the asm-generic version of
the header to remove the ARM special case, and second to review all
other uses of CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS to see if they
might be affected by the same problem on ARM.

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Russell King &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: 8635/1: nommu: allow enabling REMAP_VECTORS_TO_RAM</title>
<updated>2017-10-08T08:11:19+00:00</updated>
<author>
<name>Afzal Mohammed</name>
<email>afzal.mohd.ma@gmail.com</email>
</author>
<published>2017-01-07T16:48:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8c28f327914153bba849ddefc0d84699471ae295'/>
<id>8c28f327914153bba849ddefc0d84699471ae295</id>
<content type='text'>
[ Upstream commit 8a792e9afbce84a0fdaf213fe42bb97382487094 ]

REMAP_VECTORS_TO_RAM depends on DRAM_BASE, but since DRAM_BASE is a
hex, REMAP_VECTORS_TO_RAM could never get enabled. Also depending on
DRAM_BASE is redundant as whenever REMAP_VECTORS_TO_RAM makes itself
available to Kconfig, DRAM_BASE also is available as the Kconfig
gets sourced on !MMU.

Signed-off-by: Afzal Mohammed &lt;afzal.mohd.ma@gmail.com&gt;
Reviewed-by: Vladimir Murzin &lt;vladimir.murzin@arm.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.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>
[ Upstream commit 8a792e9afbce84a0fdaf213fe42bb97382487094 ]

REMAP_VECTORS_TO_RAM depends on DRAM_BASE, but since DRAM_BASE is a
hex, REMAP_VECTORS_TO_RAM could never get enabled. Also depending on
DRAM_BASE is redundant as whenever REMAP_VECTORS_TO_RAM makes itself
available to Kconfig, DRAM_BASE also is available as the Kconfig
gets sourced on !MMU.

Signed-off-by: Afzal Mohammed &lt;afzal.mohd.ma@gmail.com&gt;
Reviewed-by: Vladimir Murzin &lt;vladimir.murzin@arm.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>swiotlb-xen: implement xen_swiotlb_dma_mmap callback</title>
<updated>2017-10-05T07:35:53+00:00</updated>
<author>
<name>Stefano Stabellini</name>
<email>stefano.stabellini@eu.citrix.com</email>
</author>
<published>2017-02-07T17:58:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bc9f6868dfb50ba357d4db5916632c94f8d94a4c'/>
<id>bc9f6868dfb50ba357d4db5916632c94f8d94a4c</id>
<content type='text'>
commit 7e91c7df29b5e196de3dc6f086c8937973bd0b88 upstream.

This function creates userspace mapping for the DMA-coherent memory.

Signed-off-by: Stefano Stabellini &lt;stefano.stabellini@eu.citrix.com&gt;
Signed-off-by: Oleksandr Dmytryshyn &lt;oleksandr.dmytryshyn@globallogic.com&gt;
Signed-off-by: Andrii Anisov &lt;andrii_anisov@epam.com&gt;
Signed-off-by: Konrad Rzeszutek Wilk &lt;konrad@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 7e91c7df29b5e196de3dc6f086c8937973bd0b88 upstream.

This function creates userspace mapping for the DMA-coherent memory.

Signed-off-by: Stefano Stabellini &lt;stefano.stabellini@eu.citrix.com&gt;
Signed-off-by: Oleksandr Dmytryshyn &lt;oleksandr.dmytryshyn@globallogic.com&gt;
Signed-off-by: Andrii Anisov &lt;andrii_anisov@epam.com&gt;
Signed-off-by: Konrad Rzeszutek Wilk &lt;konrad@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 8692/1: mm: abort uaccess retries upon fatal signal</title>
<updated>2017-09-13T21:03:47+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2017-08-22T10:36:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=43d51814b7b3d57fbf7bac41f1f495adca6cd7f9'/>
<id>43d51814b7b3d57fbf7bac41f1f495adca6cd7f9</id>
<content type='text'>
commit 746a272e44141af24a02f6c9b0f65f4c4598ed42 upstream.

When there's a fatal signal pending, arm's do_page_fault()
implementation returns 0. The intent is that we'll return to the
faulting userspace instruction, delivering the signal on the way.

However, if we take a fatal signal during fixing up a uaccess, this
results in a return to the faulting kernel instruction, which will be
instantly retried, resulting in the same fault being taken forever. As
the task never reaches userspace, the signal is not delivered, and the
task is left unkillable. While the task is stuck in this state, it can
inhibit the forward progress of the system.

To avoid this, we must ensure that when a fatal signal is pending, we
apply any necessary fixup for a faulting kernel instruction. Thus we
will return to an error path, and it is up to that code to make forward
progress towards delivering the fatal signal.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Steve Capper &lt;steve.capper@arm.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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<pre>
commit 746a272e44141af24a02f6c9b0f65f4c4598ed42 upstream.

When there's a fatal signal pending, arm's do_page_fault()
implementation returns 0. The intent is that we'll return to the
faulting userspace instruction, delivering the signal on the way.

However, if we take a fatal signal during fixing up a uaccess, this
results in a return to the faulting kernel instruction, which will be
instantly retried, resulting in the same fault being taken forever. As
the task never reaches userspace, the signal is not delivered, and the
task is left unkillable. While the task is stuck in this state, it can
inhibit the forward progress of the system.

To avoid this, we must ensure that when a fatal signal is pending, we
apply any necessary fixup for a faulting kernel instruction. Thus we
will return to an error path, and it is up to that code to make forward
progress towards delivering the fatal signal.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Steve Capper &lt;steve.capper@arm.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
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