<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/arm/kernel, branch v5.10.258</title>
<subtitle>Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git</subtitle>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/'/>
<entry>
<title>ARM: VDSO: Patch out __vdso_clock_getres() if unavailable</title>
<updated>2026-03-04T12:19:23+00:00</updated>
<author>
<name>Thomas Weißschuh</name>
<email>thomas.weissschuh@linutronix.de</email>
</author>
<published>2025-12-23T06:59:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=08a70e02c36d604fcdba298d4fd774390e317c9e'/>
<id>08a70e02c36d604fcdba298d4fd774390e317c9e</id>
<content type='text'>
[ Upstream commit b9fecf0dddfc55cd7d02b0011494da3c613f7cde ]

The vDSO code hides symbols which are non-functional.
__vdso_clock_getres() was not added to this list when it got introduced.

Fixes: 052e76a31b4a ("ARM: 8931/1: Add clock_getres entry point")
Signed-off-by: Thomas Weißschuh &lt;thomas.weissschuh@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Link: https://patch.msgid.link/20251223-vdso-compat-time32-v1-6-97ea7a06a543@linutronix.de
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 b9fecf0dddfc55cd7d02b0011494da3c613f7cde ]

The vDSO code hides symbols which are non-functional.
__vdso_clock_getres() was not added to this list when it got introduced.

Fixes: 052e76a31b4a ("ARM: 8931/1: Add clock_getres entry point")
Signed-off-by: Thomas Weißschuh &lt;thomas.weissschuh@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Link: https://patch.msgid.link/20251223-vdso-compat-time32-v1-6-97ea7a06a543@linutronix.de
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>hw_breakpoint: fix single-stepping when using bpf_overflow_handler</title>
<updated>2023-09-23T09:01:05+00:00</updated>
<author>
<name>Tomislav Novak</name>
<email>tnovak@meta.com</email>
</author>
<published>2023-06-05T19:19:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=020ecfa7b676191845bed3e86b1753c13ae6667f'/>
<id>020ecfa7b676191845bed3e86b1753c13ae6667f</id>
<content type='text'>
[ Upstream commit d11a69873d9a7435fe6a48531e165ab80a8b1221 ]

Arm platforms use is_default_overflow_handler() to determine if the
hw_breakpoint code should single-step over the breakpoint trigger or
let the custom handler deal with it.

Since bpf_overflow_handler() currently isn't recognized as a default
handler, attaching a BPF program to a PERF_TYPE_BREAKPOINT event causes
it to keep firing (the instruction triggering the data abort exception
is never skipped). For example:

  # bpftrace -e 'watchpoint:0x10000:4:w { print("hit") }' -c ./test
  Attaching 1 probe...
  hit
  hit
  [...]
  ^C

(./test performs a single 4-byte store to 0x10000)

This patch replaces the check with uses_default_overflow_handler(),
which accounts for the bpf_overflow_handler() case by also testing
if one of the perf_event_output functions gets invoked indirectly,
via orig_default_handler.

Signed-off-by: Tomislav Novak &lt;tnovak@meta.com&gt;
Tested-by: Samuel Gosselin &lt;sgosselin@google.com&gt; # arm64
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Acked-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Link: https://lore.kernel.org/linux-arm-kernel/20220923203644.2731604-1-tnovak@fb.com/
Link: https://lore.kernel.org/r/20230605191923.1219974-1-tnovak@meta.com
Signed-off-by: Will Deacon &lt;will@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 d11a69873d9a7435fe6a48531e165ab80a8b1221 ]

Arm platforms use is_default_overflow_handler() to determine if the
hw_breakpoint code should single-step over the breakpoint trigger or
let the custom handler deal with it.

Since bpf_overflow_handler() currently isn't recognized as a default
handler, attaching a BPF program to a PERF_TYPE_BREAKPOINT event causes
it to keep firing (the instruction triggering the data abort exception
is never skipped). For example:

  # bpftrace -e 'watchpoint:0x10000:4:w { print("hit") }' -c ./test
  Attaching 1 probe...
  hit
  hit
  [...]
  ^C

(./test performs a single 4-byte store to 0x10000)

This patch replaces the check with uses_default_overflow_handler(),
which accounts for the bpf_overflow_handler() case by also testing
if one of the perf_event_output functions gets invoked indirectly,
via orig_default_handler.

Signed-off-by: Tomislav Novak &lt;tnovak@meta.com&gt;
Tested-by: Samuel Gosselin &lt;sgosselin@google.com&gt; # arm64
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Acked-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Link: https://lore.kernel.org/linux-arm-kernel/20220923203644.2731604-1-tnovak@fb.com/
Link: https://lore.kernel.org/r/20230605191923.1219974-1-tnovak@meta.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: module: Use module_init_layout_section() to spot init sections</title>
<updated>2023-09-02T07:18:13+00:00</updated>
<author>
<name>James Morse</name>
<email>james.morse@arm.com</email>
</author>
<published>2023-08-01T14:54:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=df3427204f1d75e369f691d3dc95f5e27b50728d'/>
<id>df3427204f1d75e369f691d3dc95f5e27b50728d</id>
<content type='text'>
commit a6846234f45801441f0e31a8b37f901ef0abd2df upstream.

Today module_frob_arch_sections() spots init sections from their
'init' prefix, and uses this to keep the init PLTs separate from the rest.

get_module_plt() uses within_module_init() to determine if a
location is in the init text or not, but this depends on whether
core code thought this was an init section.

Naturally the logic is different.

module_init_layout_section() groups the init and exit text together if
module unloading is disabled, as the exit code will never run. The result
is kernels with this configuration can't load all their modules because
there are not enough PLTs for the combined init+exit section.

A previous patch exposed module_init_layout_section(), use that so the
logic is the same.

Fixes: 055f23b74b20 ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: stable@vger.kernel.org
Signed-off-by: James Morse &lt;james.morse@arm.com&gt;
Signed-off-by: Luis Chamberlain &lt;mcgrof@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 a6846234f45801441f0e31a8b37f901ef0abd2df upstream.

Today module_frob_arch_sections() spots init sections from their
'init' prefix, and uses this to keep the init PLTs separate from the rest.

get_module_plt() uses within_module_init() to determine if a
location is in the init text or not, but this depends on whether
core code thought this was an init section.

Naturally the logic is different.

module_init_layout_section() groups the init and exit text together if
module unloading is disabled, as the exit code will never run. The result
is kernels with this configuration can't load all their modules because
there are not enough PLTs for the combined init+exit section.

A previous patch exposed module_init_layout_section(), use that so the
logic is the same.

Fixes: 055f23b74b20 ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: stable@vger.kernel.org
Signed-off-by: James Morse &lt;james.morse@arm.com&gt;
Signed-off-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: cpu: Switch to arch_cpu_finalize_init()</title>
<updated>2023-08-08T17:57:36+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2023-06-13T23:39:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=c0fff20d4efa3bdb3ef203a8ae6e703e0c010199'/>
<id>c0fff20d4efa3bdb3ef203a8ae6e703e0c010199</id>
<content type='text'>
commit ee31bb0524a2e7c99b03f50249a411cc1eaa411f upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/20230613224545.078124882@linutronix.de
Signed-off-by: Daniel Sneddon &lt;daniel.sneddon@linux.intel.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 ee31bb0524a2e7c99b03f50249a411cc1eaa411f upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/20230613224545.078124882@linutronix.de
Signed-off-by: Daniel Sneddon &lt;daniel.sneddon@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 9295/1: unwind:fix unwind abort for uleb128 case</title>
<updated>2023-06-09T08:30:08+00:00</updated>
<author>
<name>Haibo Li</name>
<email>haibo.li@mediatek.com</email>
</author>
<published>2023-04-17T09:17:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=16ee4562c7bb9ef0cf814eac12dea55170aca0b5'/>
<id>16ee4562c7bb9ef0cf814eac12dea55170aca0b5</id>
<content type='text'>
[ Upstream commit fa3eeb638de0c1a9d2d860e5b48259facdd65176 ]

When unwind instruction is 0xb2,the subsequent instructions
are uleb128 bytes.
For now,it uses only the first uleb128 byte in code.

For vsp increments of 0x204~0x400,use one uleb128 byte like below:
0xc06a00e4 &lt;unwind_test_work&gt;: 0x80b27fac
  Compact model index: 0
  0xb2 0x7f vsp = vsp + 1024
  0xac      pop {r4, r5, r6, r7, r8, r14}

For vsp increments larger than 0x400,use two uleb128 bytes like below:
0xc06a00e4 &lt;unwind_test_work&gt;: @0xc0cc9e0c
  Compact model index: 1
  0xb2 0x81 0x01 vsp = vsp + 1032
  0xac      pop {r4, r5, r6, r7, r8, r14}
The unwind works well since the decoded uleb128 byte is also 0x81.

For vsp increments larger than 0x600,use two uleb128 bytes like below:
0xc06a00e4 &lt;unwind_test_work&gt;: @0xc0cc9e0c
  Compact model index: 1
  0xb2 0x81 0x02 vsp = vsp + 1544
  0xac      pop {r4, r5, r6, r7, r8, r14}
In this case,the decoded uleb128 result is 0x101(vsp=0x204+(0x101&lt;&lt;2)).
While the uleb128 used in code is 0x81(vsp=0x204+(0x81&lt;&lt;2)).
The unwind aborts at this frame since it gets incorrect vsp.

To fix this,add uleb128 decode to cover all the above case.

Signed-off-by: Haibo Li &lt;haibo.li@mediatek.com&gt;
Reviewed-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Reviewed-by: Alexandre Mergnat &lt;amergnat@baylibre.com&gt;
Reviewed-by: AngeloGioacchino Del Regno &lt;angelogioacchino.delregno@collabora.com&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 fa3eeb638de0c1a9d2d860e5b48259facdd65176 ]

When unwind instruction is 0xb2,the subsequent instructions
are uleb128 bytes.
For now,it uses only the first uleb128 byte in code.

For vsp increments of 0x204~0x400,use one uleb128 byte like below:
0xc06a00e4 &lt;unwind_test_work&gt;: 0x80b27fac
  Compact model index: 0
  0xb2 0x7f vsp = vsp + 1024
  0xac      pop {r4, r5, r6, r7, r8, r14}

For vsp increments larger than 0x400,use two uleb128 bytes like below:
0xc06a00e4 &lt;unwind_test_work&gt;: @0xc0cc9e0c
  Compact model index: 1
  0xb2 0x81 0x01 vsp = vsp + 1032
  0xac      pop {r4, r5, r6, r7, r8, r14}
The unwind works well since the decoded uleb128 byte is also 0x81.

For vsp increments larger than 0x600,use two uleb128 bytes like below:
0xc06a00e4 &lt;unwind_test_work&gt;: @0xc0cc9e0c
  Compact model index: 1
  0xb2 0x81 0x02 vsp = vsp + 1544
  0xac      pop {r4, r5, r6, r7, r8, r14}
In this case,the decoded uleb128 result is 0x101(vsp=0x204+(0x101&lt;&lt;2)).
While the uleb128 used in code is 0x81(vsp=0x204+(0x81&lt;&lt;2)).
The unwind aborts at this frame since it gets incorrect vsp.

To fix this,add uleb128 decode to cover all the above case.

Signed-off-by: Haibo Li &lt;haibo.li@mediatek.com&gt;
Reviewed-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Reviewed-by: Alexandre Mergnat &lt;amergnat@baylibre.com&gt;
Reviewed-by: AngeloGioacchino Del Regno &lt;angelogioacchino.delregno@collabora.com&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>exit: Add and use make_task_dead.</title>
<updated>2023-02-01T07:23:19+00:00</updated>
<author>
<name>Eric W. Biederman</name>
<email>ebiederm@xmission.com</email>
</author>
<published>2023-01-24T19:29:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=d9c740c765e5b5d27bc6e7a500430a9bd4e14e75'/>
<id>d9c740c765e5b5d27bc6e7a500430a9bd4e14e75</id>
<content type='text'>
commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream.

There are two big uses of do_exit.  The first is it's design use to be
the guts of the exit(2) system call.  The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.

Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure.  In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.

Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.

As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.

Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
Signed-off-by: Eric Biggers &lt;ebiggers@google.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>
commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream.

There are two big uses of do_exit.  The first is it's design use to be
the guts of the exit(2) system call.  The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.

Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure.  In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.

Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.

As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.

Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
Signed-off-by: Eric Biggers &lt;ebiggers@google.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arch: setup PF_IO_WORKER threads like PF_KTHREAD</title>
<updated>2023-01-04T10:39:22+00:00</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2021-02-17T15:48:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=320c8057eceb18c5d836fcbe0ffb0035fcfe28ff'/>
<id>320c8057eceb18c5d836fcbe0ffb0035fcfe28ff</id>
<content type='text'>
[ Upstream commit 4727dc20e0422211a0e0c72b1ace4ed6096df8a6 ]

PF_IO_WORKER are kernel threads too, but they aren't PF_KTHREAD in the
sense that we don't assign -&gt;set_child_tid with our own structure. Just
ensure that every arch sets up the PF_IO_WORKER threads like kthreads
in the arch implementation of copy_thread().

Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&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 4727dc20e0422211a0e0c72b1ace4ed6096df8a6 ]

PF_IO_WORKER are kernel threads too, but they aren't PF_KTHREAD in the
sense that we don't assign -&gt;set_child_tid with our own structure. Just
ensure that every arch sets up the PF_IO_WORKER threads like kthreads
in the arch implementation of copy_thread().

Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm: add support for TIF_NOTIFY_SIGNAL</title>
<updated>2023-01-04T10:39:20+00:00</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2020-10-09T22:00:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=1bee9dbbcabbb77617fb257f964628b50ba2529c'/>
<id>1bee9dbbcabbb77617fb257f964628b50ba2529c</id>
<content type='text'>
[ Upstream commit 32d59773da38cd83e497a70eb9754d4bbae3aeae ]

Wire up TIF_NOTIFY_SIGNAL handling for arm.

Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&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 32d59773da38cd83e497a70eb9754d4bbae3aeae ]

Wire up TIF_NOTIFY_SIGNAL handling for arm.

Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 9197/1: spectre-bhb: fix loop8 sequence for Thumb2</title>
<updated>2022-05-25T07:17:59+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2022-04-20T08:46:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=a89888648e0cbc7dd1a46bac3955810fa32b04ad'/>
<id>a89888648e0cbc7dd1a46bac3955810fa32b04ad</id>
<content type='text'>
[ Upstream commit 3cfb3019979666bdf33a1010147363cf05e0f17b ]

In Thumb2, 'b . + 4' produces a branch instruction that uses a narrow
encoding, and so it does not jump to the following instruction as
expected. So use W(b) instead.

Fixes: 6c7cb60bff7a ("ARM: fix Thumb2 regression with Spectre BHB")
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: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 3cfb3019979666bdf33a1010147363cf05e0f17b ]

In Thumb2, 'b . + 4' produces a branch instruction that uses a narrow
encoding, and so it does not jump to the following instruction as
expected. So use W(b) instead.

Fixes: 6c7cb60bff7a ("ARM: fix Thumb2 regression with Spectre BHB")
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: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 9191/1: arm/stacktrace, kasan: Silence KASAN warnings in unwind_frame()</title>
<updated>2022-05-25T07:17:54+00:00</updated>
<author>
<name>linyujun</name>
<email>linyujun809@huawei.com</email>
</author>
<published>2022-04-01T09:52:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=aca18bacdb7174455f89adc3ca8ee86fae09bfc1'/>
<id>aca18bacdb7174455f89adc3ca8ee86fae09bfc1</id>
<content type='text'>
[ Upstream commit 9be4c88bb7924f68f88cfd47d925c2d046f51a73 ]

The following KASAN warning is detected by QEMU.

==================================================================
BUG: KASAN: stack-out-of-bounds in unwind_frame+0x508/0x870
Read of size 4 at addr c36bba90 by task cat/163

CPU: 1 PID: 163 Comm: cat Not tainted 5.10.0-rc1 #40
Hardware name: ARM-Versatile Express
[&lt;c0113fac&gt;] (unwind_backtrace) from [&lt;c010e71c&gt;] (show_stack+0x10/0x14)
[&lt;c010e71c&gt;] (show_stack) from [&lt;c0b805b4&gt;] (dump_stack+0x98/0xb0)
[&lt;c0b805b4&gt;] (dump_stack) from [&lt;c0b7d658&gt;] (print_address_description.constprop.0+0x58/0x4bc)
[&lt;c0b7d658&gt;] (print_address_description.constprop.0) from [&lt;c031435c&gt;] (kasan_report+0x154/0x170)
[&lt;c031435c&gt;] (kasan_report) from [&lt;c0113c44&gt;] (unwind_frame+0x508/0x870)
[&lt;c0113c44&gt;] (unwind_frame) from [&lt;c010e298&gt;] (__save_stack_trace+0x110/0x134)
[&lt;c010e298&gt;] (__save_stack_trace) from [&lt;c01ce0d8&gt;] (stack_trace_save+0x8c/0xb4)
[&lt;c01ce0d8&gt;] (stack_trace_save) from [&lt;c0313520&gt;] (kasan_set_track+0x38/0x60)
[&lt;c0313520&gt;] (kasan_set_track) from [&lt;c0314cb8&gt;] (kasan_set_free_info+0x20/0x2c)
[&lt;c0314cb8&gt;] (kasan_set_free_info) from [&lt;c0313474&gt;] (__kasan_slab_free+0xec/0x120)
[&lt;c0313474&gt;] (__kasan_slab_free) from [&lt;c0311e20&gt;] (kmem_cache_free+0x7c/0x334)
[&lt;c0311e20&gt;] (kmem_cache_free) from [&lt;c01c35dc&gt;] (rcu_core+0x390/0xccc)
[&lt;c01c35dc&gt;] (rcu_core) from [&lt;c01013a8&gt;] (__do_softirq+0x180/0x518)
[&lt;c01013a8&gt;] (__do_softirq) from [&lt;c0135214&gt;] (irq_exit+0x9c/0xe0)
[&lt;c0135214&gt;] (irq_exit) from [&lt;c01a40e4&gt;] (__handle_domain_irq+0xb0/0x110)
[&lt;c01a40e4&gt;] (__handle_domain_irq) from [&lt;c0691248&gt;] (gic_handle_irq+0xa0/0xb8)
[&lt;c0691248&gt;] (gic_handle_irq) from [&lt;c0100b0c&gt;] (__irq_svc+0x6c/0x94)
Exception stack(0xc36bb928 to 0xc36bb970)
b920:                   c36bb9c0 00000000 c0126919 c0101228 c36bb9c0 b76d7730
b940: c36b8000 c36bb9a0 c3335b00 c01ce0d8 00000003 c36bba3c c36bb940 c36bb978
b960: c010e298 c011373c 60000013 ffffffff
[&lt;c0100b0c&gt;] (__irq_svc) from [&lt;c011373c&gt;] (unwind_frame+0x0/0x870)
[&lt;c011373c&gt;] (unwind_frame) from [&lt;00000000&gt;] (0x0)

The buggy address belongs to the page:
page:(ptrval) refcount:0 mapcount:0 mapping:00000000 index:0x0 pfn:0x636bb
flags: 0x0()
raw: 00000000 00000000 ef867764 00000000 00000000 00000000 ffffffff 00000000
page dumped because: kasan: bad access detected

addr c36bba90 is located in stack of task cat/163 at offset 48 in frame:
 stack_trace_save+0x0/0xb4

this frame has 1 object:
 [32, 48) 'trace'

Memory state around the buggy address:
 c36bb980: f1 f1 f1 f1 00 04 f2 f2 00 00 f3 f3 00 00 00 00
 c36bba00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
&gt;c36bba80: 00 00 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
                 ^
 c36bbb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 c36bbb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

There is a same issue on x86 and has been resolved by the commit f7d27c35ddff
("x86/mm, kasan: Silence KASAN warnings in get_wchan()").
The solution could be applied to arm architecture too.

Signed-off-by: Lin Yujun &lt;linyujun809@huawei.com&gt;
Reported-by: He Ying &lt;heying24@huawei.com&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
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<pre>
[ Upstream commit 9be4c88bb7924f68f88cfd47d925c2d046f51a73 ]

The following KASAN warning is detected by QEMU.

==================================================================
BUG: KASAN: stack-out-of-bounds in unwind_frame+0x508/0x870
Read of size 4 at addr c36bba90 by task cat/163

CPU: 1 PID: 163 Comm: cat Not tainted 5.10.0-rc1 #40
Hardware name: ARM-Versatile Express
[&lt;c0113fac&gt;] (unwind_backtrace) from [&lt;c010e71c&gt;] (show_stack+0x10/0x14)
[&lt;c010e71c&gt;] (show_stack) from [&lt;c0b805b4&gt;] (dump_stack+0x98/0xb0)
[&lt;c0b805b4&gt;] (dump_stack) from [&lt;c0b7d658&gt;] (print_address_description.constprop.0+0x58/0x4bc)
[&lt;c0b7d658&gt;] (print_address_description.constprop.0) from [&lt;c031435c&gt;] (kasan_report+0x154/0x170)
[&lt;c031435c&gt;] (kasan_report) from [&lt;c0113c44&gt;] (unwind_frame+0x508/0x870)
[&lt;c0113c44&gt;] (unwind_frame) from [&lt;c010e298&gt;] (__save_stack_trace+0x110/0x134)
[&lt;c010e298&gt;] (__save_stack_trace) from [&lt;c01ce0d8&gt;] (stack_trace_save+0x8c/0xb4)
[&lt;c01ce0d8&gt;] (stack_trace_save) from [&lt;c0313520&gt;] (kasan_set_track+0x38/0x60)
[&lt;c0313520&gt;] (kasan_set_track) from [&lt;c0314cb8&gt;] (kasan_set_free_info+0x20/0x2c)
[&lt;c0314cb8&gt;] (kasan_set_free_info) from [&lt;c0313474&gt;] (__kasan_slab_free+0xec/0x120)
[&lt;c0313474&gt;] (__kasan_slab_free) from [&lt;c0311e20&gt;] (kmem_cache_free+0x7c/0x334)
[&lt;c0311e20&gt;] (kmem_cache_free) from [&lt;c01c35dc&gt;] (rcu_core+0x390/0xccc)
[&lt;c01c35dc&gt;] (rcu_core) from [&lt;c01013a8&gt;] (__do_softirq+0x180/0x518)
[&lt;c01013a8&gt;] (__do_softirq) from [&lt;c0135214&gt;] (irq_exit+0x9c/0xe0)
[&lt;c0135214&gt;] (irq_exit) from [&lt;c01a40e4&gt;] (__handle_domain_irq+0xb0/0x110)
[&lt;c01a40e4&gt;] (__handle_domain_irq) from [&lt;c0691248&gt;] (gic_handle_irq+0xa0/0xb8)
[&lt;c0691248&gt;] (gic_handle_irq) from [&lt;c0100b0c&gt;] (__irq_svc+0x6c/0x94)
Exception stack(0xc36bb928 to 0xc36bb970)
b920:                   c36bb9c0 00000000 c0126919 c0101228 c36bb9c0 b76d7730
b940: c36b8000 c36bb9a0 c3335b00 c01ce0d8 00000003 c36bba3c c36bb940 c36bb978
b960: c010e298 c011373c 60000013 ffffffff
[&lt;c0100b0c&gt;] (__irq_svc) from [&lt;c011373c&gt;] (unwind_frame+0x0/0x870)
[&lt;c011373c&gt;] (unwind_frame) from [&lt;00000000&gt;] (0x0)

The buggy address belongs to the page:
page:(ptrval) refcount:0 mapcount:0 mapping:00000000 index:0x0 pfn:0x636bb
flags: 0x0()
raw: 00000000 00000000 ef867764 00000000 00000000 00000000 ffffffff 00000000
page dumped because: kasan: bad access detected

addr c36bba90 is located in stack of task cat/163 at offset 48 in frame:
 stack_trace_save+0x0/0xb4

this frame has 1 object:
 [32, 48) 'trace'

Memory state around the buggy address:
 c36bb980: f1 f1 f1 f1 00 04 f2 f2 00 00 f3 f3 00 00 00 00
 c36bba00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
&gt;c36bba80: 00 00 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
                 ^
 c36bbb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 c36bbb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

There is a same issue on x86 and has been resolved by the commit f7d27c35ddff
("x86/mm, kasan: Silence KASAN warnings in get_wchan()").
The solution could be applied to arm architecture too.

Signed-off-by: Lin Yujun &lt;linyujun809@huawei.com&gt;
Reported-by: He Ying &lt;heying24@huawei.com&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
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