linux-stable.git/Documentation, branch v6.18.44

hwmon: (ina2xx) Add support for INA234

2026-08-09T18:25:03+00:00

[ Upstream commit 88a928eebccdc5445d874ddcbf1683b76c9f1431 ]

INA234 is register compatible to INA226 (excepting manufacturer and die
or device id registers) but has different scaling.

Signed-off-by: Ian Ray 
Reviewed-by: Bence Csókás  # v2
Tested-by: Jens Almer 
Tested-by: Jonas Rebmann 
Link: https://lore.kernel.org/r/20260220112024.97446-4-ian.ray@gehealthcare.com
Signed-off-by: Guenter Roeck 
Stable-dep-of: e6c80061ca23 ("hwmon: (ina2xx) Fix various overflow issues")
Signed-off-by: Sasha Levin

hwmon: (ina2xx) Make it easier to add more devices

2026-08-09T18:25:03+00:00

[ Upstream commit f6e14b5bcabf4ee97a2d535c3c2d7e72c8da4c15 ]

* Make sysfs entries documentation easier to maintain.
* Use multi-line enum.
* Correct "has_power_average" comment.

Create a new "has_update_interval" member for chips which support
averaging.

Signed-off-by: Ian Ray 
Reviewed-by: Bence Csókás  # v2
Tested-by: Jens Almer 
Link: https://lore.kernel.org/r/20260220112024.97446-3-ian.ray@gehealthcare.com
Signed-off-by: Guenter Roeck 
Stable-dep-of: e6c80061ca23 ("hwmon: (ina2xx) Fix various overflow issues")
Signed-off-by: Sasha Levin

KVM: arm64: Reject guest_memfd memslots when the VM has MTE

2026-08-09T18:25:00+00:00

[ Upstream commit 679d7201c1f09e37fa1c12ce28d84079c17fc87f ]

The user cannot use MTE on VMAs created by mapping a guest_memfd file,
as arch_calc_vm_flag_bits() does not set VM_MTE_ALLOWED.

When creating a guest_memfd backed memslot,
kvm_arch_prepare_memory_region() rejects the memslot if MTE is enabled for
the VM and if guest_memfd has been mapped in a VMA that intersects the
memslot.

However, the documentation for KVM_SET_USER_MEMORY_REGION2 explicitly
states that the only condition for userspace_addr is for it to be a legal
userspace address, but the mapping is not required to be valid nor
populated at memslot creation.

If userspace sets userspace_addr to an address that hasn't been mapped, or
if userspace_addr belongs to a VMA that isn't backed by the guest_memfd
file, or if the VMA doesn't intersect the memslot, memslot creation is
successful and KVM ends up with a VM with MTE and guest_memfd-backed
memslots.

The same happens if the order is reversed: when userspace enables MTE, KVM
does not check if memslots backed by guest_memfd are already present.

Fix both issues by rejecting guest_memfd-backed memslots when MTE is
enabled, and by rejecting MTE when guest_memfd-backed memslots are already
present.

Fixes: 32e200bd6e44 ("KVM: arm64: Enable support for guest_memfd backed memory")
Tested-by: Fuad Tabba 
Reviewed-by: Fuad Tabba 
Signed-off-by: Alexandru Elisei 
Link: https://patch.msgid.link/20260722090354.94245-1-alexandru.elisei@arm.com
Signed-off-by: Marc Zyngier 
Signed-off-by: Sasha Levin

gpu: Move DRM buddy allocator one level up (part two)

2026-08-03T09:22:09+00:00

[ Upstream commit ba110db8e1bc206c13fd7d985e79b033f53bfdea ]

Move the DRM buddy allocator one level up so that it can be used by GPU
drivers (example, nova-core) that have usecases other than DRM (such as
VFIO vGPU support). Modify the API, structures and Kconfigs to use
"gpu_buddy" terminology. Adapt the drivers and tests to use the new API.

The commit cannot be split due to bisectability, however no functional
change is intended. Verified by running K-UNIT tests and build tested
various configurations.

Signed-off-by: Joel Fernandes 
Reviewed-by: Dave Airlie 
[airlied: I've split this into two so git can find copies easier.
I've also just nuked drm_random library, that stuff needs to be done
elsewhere and only the buddy tests seem to be using it].
Signed-off-by: Dave Airlie 
Stable-dep-of: 56bc6384314f ("gpu/buddy: bail out of try_harder when alignment cannot be honoured")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

netlink: specs: rt-link: convert bridge port flag attributes to u8

2026-08-03T09:21:40+00:00

[ Upstream commit f6e3b21608e974c4aaa4cfd73a239dacf1d8a9a3 ]

A number of IFLA_BRPORT_* attributes are documented in the rt-link spec
as having the "flag" type, i.e. a payload-less NLA_FLAG attribute whose
meaning is presence-only. This does not match the kernel, which emits
these attributes with nla_put_u8() and validates them as NLA_U8 in
br_port_policy[]. The values are not mere presence flags but carry a u8
payload (0/1).

Convert these bridge port attributes from "flag" to "u8" so the spec
reflects the actual wire format.

Fixes: 077b6022d24b ("doc/netlink/specs: Add sub-message type to rt_link family")
Reviewed-by: Petr Machata 
Acked-by: Nikolay Aleksandrov 
Reviewed-by: Ido Schimmel 
Signed-off-by: Danielle Ratson 
Link: https://patch.msgid.link/a57cdfcfc4a6dcb92106c25b4dde5059fde2bd44.1783236731.git.danieller@nvidia.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

PCI: Move Resizable BAR code to rebar.c

2026-07-24T14:17:21+00:00

[ Upstream commit 9f71938cd77f32a448f40a288e409eca60e55486 ]

For lack of a better place to put it, Resizable BAR code has been placed
inside pci.c and setup-res.c that do not use it for anything.  Upcoming
changes are going to add more Resizable BAR related functions, increasing
the code size.

As pci.c is huge as is, move the Resizable BAR related code and the BAR
resize code from setup-res.c to rebar.c.

Signed-off-by: Ilpo Järvinen 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Christian König 
Link: https://patch.msgid.link/20251113180053.27944-2-ilpo.jarvinen@linux.intel.com
Stable-dep-of: ee7471fe968d ("PCI: Skip Resizable BAR restore on read error")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

cpu/hotplug: Fix NULL kobject warning in cpuhp_smt_enable()

2026-07-24T14:17:16+00:00

commit f9a82544c7174851f5c7524622f5966dcafd3a47 upstream.

On arm64, when booting with `maxcpus` greater than the number of present
CPUs (e.g., QEMU -smp cpus=4,maxcpus=8), some CPUs are marked as 'present'
but have not yet been registered via register_cpu(). Consequently,
the per-cpu device objects for these CPUs are not yet initialized.

In cpuhp_smt_enable(), the code iterates over all present CPUs. Calling
_cpu_up() for these unregistered CPUs eventually leads to
sysfs_create_group() being called with a NULL kobject (or a kobject
without a directory), triggering the following warning in
fs/sysfs/group.c:

  WARNING: fs/sysfs/group.c:137 at internal_create_group+0x41c/0x4bc, CPU#2: sh/181
  [...]
  Call trace:
    internal_create_group+0x41c/0x4bc (P)
    sysfs_create_group+0x18/0x24
    topology_add_dev+0x1c/0x28
    cpuhp_invoke_callback+0x104/0x20c
    __cpuhp_invoke_callback_range+0x94/0x11c
    _cpu_up+0x200/0x37c

When booting with ACPI, arm64 smp_prepare_cpus() currently sets all
enumerated CPUs as "present" regardless of their status in the MADT. This
causes issues with SMT hotplug control. For instance, with QEMU's
"-smp 4,maxcpus=8" configuration, the MADT GICC entries are populated as
follows:

1. The first four CPUs: `Enabled` set but `Online Capable` not set.

2. The remaining four CPUs: `Online Capable` set but `Enabled` not set
   to support potential hot-plugging.

Fix this by:

1. When booting with ACPI, checking the ACPI_MADT_ENABLED flag in the GICC
   entry before calling set_cpu_present() during SMP initialization.

2. Properly managing the present mask in acpi_map_cpu() and
   acpi_unmap_cpu() to support actual CPU hotplug events, This aligns with
   other architectures like x86 and LoongArch.

3. Update the arm64 CPU hotplug documentation to no longer state that all
   online-capable vCPUs are marked as present by the kernel at boot time.

This ensures that only physically available or explicitly enabled CPUs
are in the present mask, keeping the SMT control logic consistent with
the actual hardware state.

Cc: Catalin Marinas 
Cc: Jonathan Cameron 
Cc: James Morse 
Cc: Yicong Yang 
Cc: stable@vger.kernel.org
Link: https://uefi.org/specs/ACPI/6.5/05_ACPI_Software_Programming_Model.html#gic-cpu-interface-gicc-structure
Fixes: eed4583bcf9a ("arm64: Kconfig: Enable HOTPLUG_SMT")
Reviewed-by: Catalin Marinas 
Suggested-by: Catalin Marinas 
Signed-off-by: Jinjie Ruan 
Signed-off-by: Will Deacon 
Signed-off-by: Greg Kroah-Hartman

tracing/eprobes: Allow use of BTF names to dereference pointers

2026-07-24T14:16:42+00:00

[ Upstream commit 69efd863a78584b9416ed6be0e1e7349124b4a00 ]

Add syntax to the parsing of eprobes to be able to typecast a trace event
field that is a pointer to a structure.

Currently, a dereference must be a number, where the user has to figure
out manually the offset of a member of a structure that they want to
dereference.

But for event probes that records a field that happens to be a pointer to
a structure, it cannot dereference these values with BTF naming, but
must use numerical offsets.

For example, to find out what device a sk_buff is pointing to in the
net_dev_xmit trace event, one must first use gdb to find the offsets of the
members of the structures:

 (gdb) p &((struct sk_buff *)0)->dev
 $1 = (struct net_device **) 0x10
 (gdb) p &((struct net_device *)0)->name
 $2 = (char (*)[16]) 0x118

And then use the raw numbers to dereference:

  # echo 'e:xmit net.net_dev_xmit +0x118(+0x10($skbaddr)):string' >> dynamic_events

If BTF is in the kernel, then instead, the skbaddr can be typecast to
sk_buff and use the normal dereference logic.

  # echo 'e:xmit net.net_dev_xmit (sk_buff)skbaddr->dev->name:string' >> dynamic_events
  # echo 1 > events/eprobes/xmit/enable
  # cat trace
[..]
    sshd-session-1022    [000] b..2.   860.249343: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.250061: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.250142: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.263553: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.283820: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.302716: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.322905: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.342828: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.362268: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.382335: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.400856: xmit: (net.net_dev_xmit) arg1="enp7s0"
    sshd-session-1022    [000] b..2.   860.419893: xmit: (net.net_dev_xmit) arg1="enp7s0"

The syntax is simply: (STRUCT)(FIELD)->MEMBER[->MEMBER..]

Also add comments around the #else and #endif of #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
to know what they are for.

Link: https://lore.kernel.org/all/20260601130746.2139d926@gandalf.local.home/

Signed-off-by: Steven Rostedt (Google) 
Signed-off-by: Masami Hiramatsu (Google) 
Stable-dep-of: 251a8fe1b9ae ("tracing/probes: Remove WARN_ON_ONCE from parse_btf_arg")
Signed-off-by: Sasha Levin

dt-bindings: net: renesas,ether: Drop example "ethernet-phy-ieee802.3-c22" fallback

2026-07-24T14:16:40+00:00

[ Upstream commit 14eb1d2c03b38ce3427f299967f7a4d97ebff4c2 ]

Fix the Micrel PHY in the example which shouldn't have the
fallback "ethernet-phy-ieee802.3-c22" compatible:

Documentation/devicetree/bindings/net/renesas,ether.example.dtb: ethernet-phy@1 \
  (ethernet-phy-id0022.1537): compatible: ['ethernet-phy-id0022.1537', 'ethernet-phy-ieee802.3-c22'] is too long
        from schema $id: http://devicetree.org/schemas/net/micrel.yaml

Signed-off-by: Rob Herring (Arm) 
Reviewed-by: Andrew Lunn 
Acked-by: Conor Dooley 
Acked-by: Niklas Söderlund 
Fixes: 37a2fce09001 ("dt-bindings: sh_eth convert bindings to json-schema")
Link: https://patch.msgid.link/20260624150250.131966-2-robh@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

i3c: add sysfs entry and attribute for Device NACK Retry count

2026-07-24T14:16:26+00:00

[ Upstream commit b58f47eb392680d4c6626c8b3b1fcf6412a0a02c ]

Document sysfs attribute dev_nack_retry_cnt that controls the number of
automatic retries performed by the I3C controller when a target device
returns a NACK

Add a `dev_nack_retry_count` sysfs attribute to allow reading and updating
the device NACK retry count. A new `dev_nack_retry_count` field and an
optional `set_dev_nack_retry()` callback are added to
i3c_master_controller. The attribute is created only when the callback is
implemented.

Updates are applied under the I3C bus maintenance lock to ensure safe
hardware reconfiguration.

Signed-off-by: Adrian Ng Ho Yin 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/3c4b5082bde64024fc383c44bebeef89ad3c7ed3.1765529948.git.adrianhoyin.ng@altera.com
Signed-off-by: Alexandre Belloni 
Stable-dep-of: 3f79dac3ea1c ("i3c: master: Defer new-device registration out of DAA caller context")
Signed-off-by: Sasha Levin