linux-stable.git/Documentation, branch v7.1.8

scsi: ufs: dt-bindings: Add missing mcq reg for qcom,sa8255p-ufshc

2026-08-09T18:26:48+00:00

commit 4d5282c06ca198319c2de41b10511ddcb8068f42 upstream.

Qualcomm UFS controller found on SoCs SA8255P/SA8797P has a MCQ I/O address
space. It should be defined in the bindings even though Linux driver
currently doesn't utilize it. Fix the binding before it gets adopted by
DTS.

Fixes: e2725ed2a7fb ("scsi: ufs: dt-bindings: Document bindings for SA8255P UFS Host Controller")
Cc: stable@vger.kernel.org
Signed-off-by: Shawn Guo 
Acked-by: Krzysztof Kozlowski 
Link: https://patch.msgid.link/20260720023552.2667237-1-shengchao.guo@oss.qualcomm.com
Signed-off-by: Martin K. Petersen 
Signed-off-by: Greg Kroah-Hartman

erofs: remove fscache backend entirely

2026-08-09T18:26:29+00:00

[ Upstream commit c37460cd9b2fcb61ec66b7eb4fde737e65ec2a56 ]

EROFS over fscache was introduced to provide image lazy pulling
functionality. After the feature landed, the fscache subsystem made
netfs a new hard dependency, which is unexpected for a local filesystem
and has an kernel-defined caching hierarchy which could be inflexible
compared to the fanotify pre-content hooks. Therefore, this feature has
been deprecated for almost two years.

As EROFS file-backed mounts and fanotify pre-content hooks both upstream
for a while and already providing equivalent functionality (erofs-utils
has supported fanotify pre-content hooks), let's remove the fscache
backend now.

The main application of this feature is Nydus [1], and they plan to move
to use fanotify pre-content hooks in the near future too.

I hope this patch can be merged into Linux 7.2, which is also motivated
by newly found implementation issues [2][3] that are not worth
investigating given the deprecation and limited development resources.
The associated fscache/cachefiles cleanup patch will follow separately
through the vfs tree (netfs) later: it seems fine since the codebase is
isolated by CONFIG_CACHEFILES_ONDEMAND.

[1] https://github.com/dragonflyoss/nydus/blob/v2.1.0/docs/nydus-fscache.md
[2] https://github.com/dragonflyoss/nydus/pull/1824
[3] https://lore.kernel.org/r/20260619135800.1594811-1-michael.bommarito@gmail.com

Acked-by: Jingbo Xu 
Signed-off-by: Gao Xiang 
Stable-dep-of: 96b2dbbe58a1 ("erofs: ensure valid f_path for page cache sharing")
Signed-off-by: Sasha Levin

xsk: reclaim invalid Tx descriptors in ZC batch path

2026-08-09T18:26:28+00:00

[ Upstream commit 72f2b4516faf55d4dfac2414649d3cffa5fd2c5e ]

The zero-copy Tx batch parser stops when it encounters an invalid
descriptor. If this happens after one or more continuation descriptors,
the Tx consumer can be advanced past fragments that are neither submitted
to the driver nor returned to userspace through the completion ring.

A similar problem occurs when a packet exceeds xdp_zc_max_segs. The
descriptors consumed up to the limit are released without completion, and
the remaining continuation descriptors can subsequently be interpreted
as the beginning of another packet.

Parse Tx batches in packet units and distinguish descriptors belonging to
complete valid packets from descriptors consumed while draining an
invalid or oversized packet. Return the former to the driver and append
the latter to the CQ address area so userspace can reclaim their UMEM
frames.

Treat a standalone invalid descriptor as a one-descriptor reclaim-only
packet. Advancing the Tx-ring consumer releases the ring slot, but does
not by itself return ownership of the referenced UMEM frame to userspace.

Once draining starts, continue until the packet's end-of-packet
descriptor is consumed. Preserve the drain state on the socket when EOP
has not yet been supplied, so draining can continue during a later call.
Leave incomplete but otherwise valid packets on the Tx ring.

Shared-UMEM pools using multi-buffer Tx also need packet-framed parsing.
Walk their Tx sockets one packet at a time, preserving the existing
per-socket fairness scheme, instead of using the legacy one-descriptor
fallback. Keep that fallback for shared pools that do not use
multi-buffer Tx. Since the drain state is maintained per socket and both
the singular and shared paths can resume an interrupted drain, changing
the socket list from singular to shared requires no special bind-time
transition.

CQ entries are positional, and drivers may complete only part of the Tx
work returned by xsk_tx_peek_release_desc_batch(). Therefore, reclaim-only
entries cannot be published immediately when earlier driver-visible
descriptors are still outstanding.

Track the number of driver-visible CQ entries preceding the reclaim
entries. Let xsk_tx_completed() publish partial hardware Tx completions,
and publish the reclaim entries only after every earlier Tx descriptor
has completed. Complete a reclaim-only batch immediately when there is no
driver-visible work in front of it, and prevent another Tx batch from
being appended while reclaim entries remain pending.

Also cap batch processing by the size of the pool's temporary descriptor
array, as Tx rings belonging to sockets sharing a UMEM may have different
sizes.

This ensures that every invalid Tx descriptor consumed by the ZC batch
path is either submitted to the driver as part of a valid packet or
returned to userspace without violating CQ completion ordering.

Reviewed-by: Jason Xing 
Signed-off-by: Maciej Fijalkowski 
Acked-by: Stanislav Fomichev 
Fixes: cf24f5a5feea ("xsk: add support for AF_XDP multi-buffer on Tx path")
Link: https://patch.msgid.link/20260719135609.147823-5-maciej.fijalkowski@intel.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

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

2026-08-09T18:26:26+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

KVM: arm64: vgic: Avoid double-deactivate of IRQs in the nested context

2026-08-09T18:26:22+00:00

commit 8a570b19b4b16a8a3b5ffa2b332bd5613110b2d8 upstream.

In the nested state, the physical interrupt has already been
deactivated through the HW bit in the LR. The extra deactivation
would be harmless but can hit an errata case on AmpereOne, so
avoid it here.

On AmpereOne, deactivating a physical interrupt through
ICC_DIR_EL1 or ICC_EOIR1_EL1 (depending on EOImode) which is not
active, but is the highest priority pending interrupt causes the
cpu to lose the interrupt pending state and also prevents the
delivery of future interrupts.

Fixes: 6dd333c8942b2 ("KVM: arm64: GICv3: nv: Plug L1 LR sync into deactivation primitive")
Signed-off-by: D Scott Phillips 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/linux-arm-kernel/20260710222128.416581-1-scott@os.amperecomputing.com/
Link: https://patch.msgid.link/20260714231158.496808-1-scott@os.amperecomputing.com
Signed-off-by: Marc Zyngier 
Signed-off-by: Greg Kroah-Hartman

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

2026-08-03T09:25:30+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

hwmon: (pmbus/max34440): add support adpm12250

2026-08-03T09:25:29+00:00

[ Upstream commit 479bfeba2eb62666cd4b981c8e721c61dcf36e7d ]

ADPM12250 is a quarter brick DC/DC Power Module. It is a high power
non-isolated converter capable of delivering regulated 12V with
continuous power level of 2500W. Uses PMBus.

Signed-off-by: Alexis Czezar Torreno 
Reviewed-by: Nuno Sá 
Link: https://lore.kernel.org/r/20260610-dev-adpm12250-v1-1-422760bb80da@analog.com
Signed-off-by: Guenter Roeck 
Stable-dep-of: af01dab0c39a ("hwmon: (pmbus/max34440) block unsupported VIN and IIN limit registers")
Signed-off-by: Sasha Levin

Docs/admin-guide/cgroup-v2: fix memory.stat doc details

2026-08-03T09:25:16+00:00

[ Upstream commit 46d65096ce8d278abf4528e254878c14ddd0b459 ]

Fix minor cgroup v2 memory.stat documentation issues.  Correct the
vmalloc per-node marker now that vmalloc uses the native NR_VMALLOC node
stat, and document zswap_incomp as a byte-valued memory amount instead
of as a page counter.

Fixes: c466412c73c3 ("mm: memcontrol: switch to native NR_VMALLOC vmstat counter")
Fixes: 5ad41a38c364 ("mm: zswap: add per-memcg stat for incompressible pages")
Signed-off-by: Doehyun Baek 
Reviewed-by: Nhat Pham 
Acked-by: Michal Koutný 
Signed-off-by: Tejun Heo 
Signed-off-by: Sasha Levin

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

2026-07-24T14:21:20+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

2026-07-24T14:20:35+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