[ Upstream commit beb3c5ad8829b52057f48a776a9d9558b98c157f ]
MCTP attribute naming is inconsistent. In C we have:
IFLA_MCTP_NET,
IFLA_MCTP_PHYS_BINDING,
^^^^
but in YAML:
- mctp-net
- phys-binding
^
no "mctp"
It's unclear whether the "mctp" part of the name is supposed
to be a prefix or part of attribute name. Make it a prefix,
seems cleaner, even tho technically phys-binding was added later.
Fixes: b2f63d904e ("doc/netlink: Add spec for rt link messages")
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250414211851.602096-8-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 3a544a39e0a4c492e3026dfbed018321d2bd6caa upstream.
The MIPID02 can use up to 2 data lanes which leads to having a maximum
item number of 3 for the lane-polarities since this also contains the
clock lane.
CC: stable@vger.kernel.org
Fixes: c2741cbe7f ("dt-bindings: media: st,stmipid02: Convert the text bindings to YAML")
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Documentation/timers/no_hz.rst states that the "nohz_full=" mask must not
include the boot CPU, which is no longer true after:
08ae95f4fd ("nohz_full: Allow the boot CPU to be nohz_full").
However after:
aae17ebb53cd ("workqueue: Avoid using isolated cpus' timers on queue_delayed_work")
the kernel will crash at boot time in this case; housekeeping_any_cpu()
returns an invalid CPU number until smp_init() brings the first
housekeeping CPU up.
Change housekeeping_any_cpu() to check the result of cpumask_any_and() and
return smp_processor_id() in this case.
This is just the simple and backportable workaround which fixes the
symptom, but smp_processor_id() at boot time should be safe at least for
type == HK_TYPE_TIMER, this more or less matches the tick_do_timer_boot_cpu
logic.
There is no worry about cpu_down(); tick_nohz_cpu_down() will not allow to
offline tick_do_timer_cpu (the 1st online housekeeping CPU).
[ Apply only documentation changes as commit which causes boot
crash when boot CPU is nohz_full is not backported to stable
kernels - Krishanth ]
Reported-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240411143905.GA19288@redhat.com
Closes: https://lore.kernel.org/all/20240402105847.GA24832@redhat.com/
Signed-off-by: Krishanth Jagaduri <Krishanth.Jagaduri@sony.com>
[ strip out upstream commit and Fixes: so tools don't get confused that
this commit actually does anything real - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9407bda845dd19756e276d4f3abc15a20777ba45 upstream
Applying microcode late can be fatal for the running kernel when the
update changes functionality which is in use already in a non-compatible
way, e.g. by removing a CPUID bit.
There is no way for admins which do not have access to the vendors deep
technical support to decide whether late loading of such a microcode is
safe or not.
Intel has added a new field to the microcode header which tells the
minimal microcode revision which is required to be active in the CPU in
order to be safe.
Provide infrastructure for handling this in the core code and a command
line switch which allows to enforce it.
If the update is considered safe the kernel is not tainted and the annoying
warning message not emitted. If it's enforced and the currently loaded
microcode revision is not safe for late loading then the load is aborted.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231017211724.079611170@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 064737920bdbca86df91b96aed256e88018fef3a upstream.
The hwcaps code that exposes SVE features to userspace only
considers ID_AA64ZFR0_EL1, while this is only valid when
ID_AA64PFR0_EL1.SVE advertises that SVE is actually supported.
The expectations are that when ID_AA64PFR0_EL1.SVE is 0, the
ID_AA64ZFR0_EL1 register is also 0. So far, so good.
Things become a bit more interesting if the HW implements SME.
In this case, a few ID_AA64ZFR0_EL1 fields indicate *SME*
features. And these fields overlap with their SVE interpretations.
But the architecture says that the SME and SVE feature sets must
match, so we're still hunky-dory.
This goes wrong if the HW implements SME, but not SVE. In this
case, we end-up advertising some SVE features to userspace, even
if the HW has none. That's because we never consider whether SVE
is actually implemented. Oh well.
Fix it by restricting all SVE capabilities to ID_AA64PFR0_EL1.SVE
being non-zero. The HWCAPS documentation is amended to reflect the
actually checks performed by the kernel.
Fixes: 06a916feca ("arm64: Expose SVE2 features for userspace")
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: stable@vger.kernel.org
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250107-arm64-2024-dpisa-v5-1-7578da51fc3d@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 6856edf7ead8c54803216a38a7b227bcb3dadff7 ]
The sense resistor used for measuring currents is typically some tens of
milli Ohms. It has accidentally been documented to be tens of mega Ohms.
Fix the size of this resistor and a few copy-paste errors while at it.
Drop the unsuitable 'rohm,charger-sense-resistor-ohms' property (which
can't represent resistors smaller than one Ohm), and introduce a new
'rohm,charger-sense-resistor-micro-ohms' property with appropriate
minimum, maximum and default values instead.
Fixes: 4238dc1e64 ("dt_bindings: mfd: Add ROHM BD71815 PMIC")
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/0efd8e9de0ae8d62ee4c6b78cc565b04007a245d.1731430700.git.mazziesaccount@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 08242719a8af603db54a2a79234a8fe600680105 ]
The "regulator-compatible" property has been deprecated since 2012 in
commit 13511def87 ("regulator: deprecate regulator-compatible DT
property"), which is so old it's not even mentioned in the converted
regulator bindings YAML file. It should not have been used for new
submissions such as the MT6315.
Drop the property from the MT6315 regulator binding and its examples.
Fixes: 977fb5b584 ("regulator: document binding for MT6315 regulator")
Fixes: 6d435a94ba ("regulator: mt6315: Enforce regulator-compatible, not name")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/20241211052427.4178367-2-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f3b78b470f28bb2a3a40e88bdf5c6de6a35a9b76 ]
HiSilicon HIP10/11 platforms using the same SMMU PMCG with HIP09
and thus suffers the same erratum. List them in the PMCG platform
information list without introducing a new SMMU PMCG Model.
Update the silicon-errata.rst as well.
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20240731092658.11012-1-yangyicong@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
Stable-dep-of: c2b46ae02270 ("ACPI/IORT: Add PMCG platform information for HiSilicon HIP09A")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 72ad4ff638047bbbdf3232178fea4bec1f429319 ]
Due to recent changes on the way we're maintaining media, the
location of the main tree was updated.
Change docs accordingly.
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 1aa772be0444a2bd06957f6d31865e80e6ae4244 upstream.
Add fsl,pps-channel property to select where to connect the PPS signal.
This depends on the internal SoC routing and on the board, for example
on the i.MX8 SoC it can be connected to an external pin (using channel 1)
or to internal eDMA as DMA request (channel 0).
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Csókás, Bence <csokas.bence@prolan.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 2fa046449a82a7d0f6d9721dd83e348816038444 ]
The "bus" and "cxl_bus" reset methods reset a device by asserting Secondary
Bus Reset on the bridge leading to the device. These only work if the
device is the only device below the bridge.
Add a sysfs 'reset_subordinate' attribute on bridges that can assert
Secondary Bus Reset regardless of how many devices are below the bridge.
This resets all the devices below a bridge in a single command, including
the locking and config space save/restore that reset methods normally do.
This may be the only way to reset devices that don't support other reset
methods (ACPI, FLR, PM reset, etc).
Link: https://lore.kernel.org/r/20241025222755.3756162-1-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
[bhelgaas: commit log, add capable(CAP_SYS_ADMIN) check]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Amey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a7a0350583ba51d8cde6180bb51d704b89a3b29e ]
ZRAM_MEMORY_TRACKING enables two features:
- per-entry ac-time tracking
- debugfs interface
The latter one is the reason why memory-tracking depends on DEBUG_FS,
while the former one is used far beyond debugging these days. Namely
ac-time is used for fine grained writeback of idle entries (pages).
Move ac-time tracking under its own config option so that it can be
enabled (along with writeback) on systems without DEBUG_FS.
[senozhatsky@chromium.org: ifdef fixup, per Dmytro]
Link: https://lkml.kernel.org/r/20231117013543.540280-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20231115024223.4133148-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dmytro Maluka <dmaluka@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: d37da422edb0 ("zram: clear IDLE flag in mark_idle()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4649cbd97fdae5069e9a71cd7669b62b90e03669 ]
Some fix and updates in the following items:
1. examples:
Update generic node name to 'audio-codec' to comply with the
coming change in 'mt6359.dtsi'. This change is necessary to fix the
dtbs_check error:
pmic: 'mt6359codec' does not match any of the regexes: 'pinctrl-[0-9]+'
2. mediatek,dmic-mode:
After inspecting the .dts and .dtsi files using 'mt6359-codec', it was
discovered that the definitions of 'two wires' and 'one wire' are
inverted compared to the DT schema.
For example, the following boards using MT6359 PMIC:
- mt8192-asurada.dtsi
- mt8195-cherry.dtsi
These boards use the same definitions of 'dmic-mode' as other boards
using MT6358 PMIC. The meaning of '0' or '1' has been noted as comments
in the device trees.
Upon examining the code in [1] and [2], it was confirmed that the
definitions of 'dmic-mode' are consistent between "MT6359 PMIC" and
"MT6358 PMIC". Therefore, the DT Schema should be correct as is.
References:
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/codecs/mt6358.c#n1875
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/codecs/mt6359.c#L1515
Fixes: 539237d1c6 ("dt-bindings: mediatek: mt6359: add codec document")
Signed-off-by: Jiaxin Yu <jiaxin.yu@mediatek.com>
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/20240930075451.14196-1-macpaul.lin@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5c1806c41ce0a0110db5dd4c483cf2dc28b3ddf0 ]
While fuzzing an arm64 kernel, Alexander Potapenko reported:
| BUG: KCSAN: data-race in ktime_get_mono_fast_ns / timekeeping_update
|
| write to 0xffffffc082e74248 of 56 bytes by interrupt on cpu 0:
| update_fast_timekeeper kernel/time/timekeeping.c:430 [inline]
| timekeeping_update+0x1d8/0x2d8 kernel/time/timekeeping.c:768
| timekeeping_advance+0x9e8/0xb78 kernel/time/timekeeping.c:2344
| update_wall_time+0x18/0x38 kernel/time/timekeeping.c:2360
| [...]
|
| read to 0xffffffc082e74258 of 8 bytes by task 5260 on cpu 1:
| __ktime_get_fast_ns kernel/time/timekeeping.c:372 [inline]
| ktime_get_mono_fast_ns+0x88/0x174 kernel/time/timekeeping.c:489
| init_srcu_struct_fields+0x40c/0x530 kernel/rcu/srcutree.c:263
| init_srcu_struct+0x14/0x20 kernel/rcu/srcutree.c:311
| [...]
|
| value changed: 0x000002f875d33266 -> 0x000002f877416866
|
| Reported by Kernel Concurrency Sanitizer on:
| CPU: 1 UID: 0 PID: 5260 Comm: syz.2.7483 Not tainted 6.12.0-rc3-dirty #78
This is a false positive data race between a seqcount latch writer and a reader
accessing stale data. Since its introduction, KCSAN has never understood the
seqcount_latch interface (due to being unannotated).
Unlike the regular seqlock interface, the seqcount_latch interface for latch
writers never has had a well-defined critical section, making it difficult to
teach tooling where the critical section starts and ends.
Introduce an instrumentable (non-raw) seqcount_latch interface, with
which we can clearly denote writer critical sections. This both helps
readability and tooling like KCSAN to understand when the writer is done
updating all latch copies.
Fixes: 88ecd153be ("seqlock, kcsan: Add annotations for KCSAN")
Reported-by: Alexander Potapenko <glider@google.com>
Co-developed-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241104161910.780003-4-elver@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 17d8adc4cd5181c13c1041b197b76efc09eaf8a8 ]
My understanding of the interrupts property is that it can either be:
1/ - TX
2/ - TX
- RX
3/ - Common/combined.
There are very little chances that either:
- TX
- Common/combined
or even
- TX
- RX
- Common/combined
could be a thing.
Looking at the interrupt-names definition (which uses oneOf instead of
anyOf), it makes indeed little sense to use anyOf in the interrupts
definition. I believe this is just a mistake, hence let's fix it.
Fixes: 8be90641a0 ("ASoC: dt-bindings: davinci-mcasp: convert McASP bindings to yaml schema")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20241001204749.390054-1-miquel.raynal@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2a0683be5b4c9829e8335e494a21d1148e832822 ]
Some tests written in bash source other files in a parent directory. For
example, drivers/net/bonding/dev_addr_lists.sh sources
net/forwarding/lib.sh. If a subset of tests is exported and run outside the
source tree (for example by using `make -C tools/testing/selftests gen_tar
TARGETS="drivers/net/bonding"`), these other files must be made available
as well.
Commit ae108c48b5 ("selftests: net: Fix cross-tree inclusion of scripts")
addressed this problem by symlinking and copying the sourced files but this
only works for direct dependencies. Commit 25ae948b4478 ("selftests/net:
add lib.sh") changed net/forwarding/lib.sh to source net/lib.sh. As a
result, that latter file must be included as well when the former is
exported. This was not handled and was reverted in commit 2114e83381d3
("selftests: forwarding: Avoid failures to source net/lib.sh"). In order to
allow reinstating the inclusion of net/lib.sh from net/forwarding/lib.sh,
add a mechanism to list dependent files in a new Makefile variable and
export them. This allows sourcing those files using the same expression
whether tests are run in-tree or exported.
Dependencies are not resolved recursively so transitive dependencies must
be listed in TEST_INCLUDES. For example, if net/forwarding/lib.sh sources
net/lib.sh; the Makefile related to a test that sources
net/forwarding/lib.sh from a parent directory must list:
TEST_INCLUDES := \
../../../net/forwarding/lib.sh \
../../../net/lib.sh
v2:
Fix rst syntax in Documentation/dev-tools/kselftest.rst (Jakub Kicinski)
v1 (from RFC):
* changed TEST_INCLUDES to take relative paths, like other TEST_* variables
(Vladimir Oltean)
* preserved common "$(MAKE) OUTPUT=... -C ... target" ordering in Makefile
(Petr Machata)
Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 081eb7932c2b244f63317a982c5e3990e2c7fbdd ]
A number of Arm Ltd CPUs suffer from errata whereby an MSR to the SSBS
special-purpose register does not affect subsequent speculative
instructions, permitting speculative store bypassing for a window of
time.
We worked around this for a number of CPUs in commits:
* 7187bb7d0b5c7dfa ("arm64: errata: Add workaround for Arm errata 3194386 and 3312417")
* 75b3c43eab594bfb ("arm64: errata: Expand speculative SSBS workaround")
* 145502cac7ea70b5 ("arm64: errata: Expand speculative SSBS workaround (again)")
Since then, a (hopefully final) batch of updates have been published,
with two more affected CPUs. For the affected CPUs the existing
mitigation is sufficient, as described in their respective Software
Developer Errata Notice (SDEN) documents:
* Cortex-A715 (MP148) SDEN v15.0, erratum 3456084
https://developer.arm.com/documentation/SDEN-2148827/1500/
* Neoverse-N3 (MP195) SDEN v5.0, erratum 3456111
https://developer.arm.com/documentation/SDEN-3050973/0500/
Enable the existing mitigation by adding the relevant MIDRs to
erratum_spec_ssbs_list, and update silicon-errata.rst and the
Kconfig text accordingly.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20240930111705.3352047-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[ Mark: fix conflict in silicon-errata.rst ]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c6929644c1e0d6108e57061d427eb966e1746351 ]
Add missing reg minItems as based on current binding document
only ethernet MAC IO space is a supported configuration.
There is a bug in schema, current examples contain 64-bit
addressing as well as 32-bit addressing. The schema validation
does pass incidentally considering one 64-bit reg address as
two 32-bit reg address entries. If we change axi_ethernet_eth1
example node reg addressing to 32-bit schema validation reports:
Documentation/devicetree/bindings/net/xlnx,axi-ethernet.example.dtb:
ethernet@40000000: reg: [[1073741824, 262144]] is too short
To fix it add missing reg minItems constraints and to make things clearer
stick to 32-bit addressing in examples.
Fixes: cbb1ca6d5f ("dt-bindings: net: xlnx,axi-ethernet: convert bindings document to yaml")
Signed-off-by: Ravikanth Tuniki <ravikanth.tuniki@amd.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/1727723615-2109795-1-git-send-email-radhey.shyam.pandey@amd.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit efbc6bd090f48ccf64f7a8dd5daea775821d57ec upstream.
The warning
Documentation/virt/kvm/locking.rst:31: ERROR: Unexpected indentation.
is caused by incorrectly treating a line as the continuation of a paragraph,
rather than as the first line in a bullet list.
Fixed: 44d174596260 ("KVM: Use dedicated mutex to protect kvm_usage_count to avoid deadlock")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 44d17459626052a2390457e550a12cb973506b2f upstream.
Use a dedicated mutex to guard kvm_usage_count to fix a potential deadlock
on x86 due to a chain of locks and SRCU synchronizations. Translating the
below lockdep splat, CPU1 #6 will wait on CPU0 #1, CPU0 #8 will wait on
CPU2 #3, and CPU2 #7 will wait on CPU1 #4 (if there's a writer, due to the
fairness of r/w semaphores).
CPU0 CPU1 CPU2
1 lock(&kvm->slots_lock);
2 lock(&vcpu->mutex);
3 lock(&kvm->srcu);
4 lock(cpu_hotplug_lock);
5 lock(kvm_lock);
6 lock(&kvm->slots_lock);
7 lock(cpu_hotplug_lock);
8 sync(&kvm->srcu);
Note, there are likely more potential deadlocks in KVM x86, e.g. the same
pattern of taking cpu_hotplug_lock outside of kvm_lock likely exists with
__kvmclock_cpufreq_notifier():
cpuhp_cpufreq_online()
|
-> cpufreq_online()
|
-> cpufreq_gov_performance_limits()
|
-> __cpufreq_driver_target()
|
-> __target_index()
|
-> cpufreq_freq_transition_begin()
|
-> cpufreq_notify_transition()
|
-> ... __kvmclock_cpufreq_notifier()
But, actually triggering such deadlocks is beyond rare due to the
combination of dependencies and timings involved. E.g. the cpufreq
notifier is only used on older CPUs without a constant TSC, mucking with
the NX hugepage mitigation while VMs are running is very uncommon, and
doing so while also onlining/offlining a CPU (necessary to generate
contention on cpu_hotplug_lock) would be even more unusual.
The most robust solution to the general cpu_hotplug_lock issue is likely
to switch vm_list to be an RCU-protected list, e.g. so that x86's cpufreq
notifier doesn't to take kvm_lock. For now, settle for fixing the most
blatant deadlock, as switching to an RCU-protected list is a much more
involved change, but add a comment in locking.rst to call out that care
needs to be taken when walking holding kvm_lock and walking vm_list.
======================================================
WARNING: possible circular locking dependency detected
6.10.0-smp--c257535a0c9d-pip #330 Tainted: G S O
------------------------------------------------------
tee/35048 is trying to acquire lock:
ff6a80eced71e0a8 (&kvm->slots_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x179/0x1e0 [kvm]
but task is already holding lock:
ffffffffc07abb08 (kvm_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x14a/0x1e0 [kvm]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (kvm_lock){+.+.}-{3:3}:
__mutex_lock+0x6a/0xb40
mutex_lock_nested+0x1f/0x30
kvm_dev_ioctl+0x4fb/0xe50 [kvm]
__se_sys_ioctl+0x7b/0xd0
__x64_sys_ioctl+0x21/0x30
x64_sys_call+0x15d0/0x2e60
do_syscall_64+0x83/0x160
entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #2 (cpu_hotplug_lock){++++}-{0:0}:
cpus_read_lock+0x2e/0xb0
static_key_slow_inc+0x16/0x30
kvm_lapic_set_base+0x6a/0x1c0 [kvm]
kvm_set_apic_base+0x8f/0xe0 [kvm]
kvm_set_msr_common+0x9ae/0xf80 [kvm]
vmx_set_msr+0xa54/0xbe0 [kvm_intel]
__kvm_set_msr+0xb6/0x1a0 [kvm]
kvm_arch_vcpu_ioctl+0xeca/0x10c0 [kvm]
kvm_vcpu_ioctl+0x485/0x5b0 [kvm]
__se_sys_ioctl+0x7b/0xd0
__x64_sys_ioctl+0x21/0x30
x64_sys_call+0x15d0/0x2e60
do_syscall_64+0x83/0x160
entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #1 (&kvm->srcu){.+.+}-{0:0}:
__synchronize_srcu+0x44/0x1a0
synchronize_srcu_expedited+0x21/0x30
kvm_swap_active_memslots+0x110/0x1c0 [kvm]
kvm_set_memslot+0x360/0x620 [kvm]
__kvm_set_memory_region+0x27b/0x300 [kvm]
kvm_vm_ioctl_set_memory_region+0x43/0x60 [kvm]
kvm_vm_ioctl+0x295/0x650 [kvm]
__se_sys_ioctl+0x7b/0xd0
__x64_sys_ioctl+0x21/0x30
x64_sys_call+0x15d0/0x2e60
do_syscall_64+0x83/0x160
entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #0 (&kvm->slots_lock){+.+.}-{3:3}:
__lock_acquire+0x15ef/0x2e30
lock_acquire+0xe0/0x260
__mutex_lock+0x6a/0xb40
mutex_lock_nested+0x1f/0x30
set_nx_huge_pages+0x179/0x1e0 [kvm]
param_attr_store+0x93/0x100
module_attr_store+0x22/0x40
sysfs_kf_write+0x81/0xb0
kernfs_fop_write_iter+0x133/0x1d0
vfs_write+0x28d/0x380
ksys_write+0x70/0xe0
__x64_sys_write+0x1f/0x30
x64_sys_call+0x281b/0x2e60
do_syscall_64+0x83/0x160
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Cc: Chao Gao <chao.gao@intel.com>
Fixes: 0bf50497f0 ("KVM: Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock")
Cc: stable@vger.kernel.org
Reviewed-by: Kai Huang <kai.huang@intel.com>
Acked-by: Kai Huang <kai.huang@intel.com>
Tested-by: Farrah Chen <farrah.chen@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240830043600.127750-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
