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Use rhashtable_lookup_likely() for lookups, rhashtable_remove_fast()
for deletes, and rhashtable_lookup_get_insert_fast() for inserts.
Updates modify values in place under RCU rather than allocating a
new element and swapping the pointer (as regular htab does). This
trades read consistency for performance: concurrent readers may
see partial updates. BPF_F_LOCK support and special-field
handling (timers, kptrs, etc.) follow in a later commit.
Initialize rhashtable with bpf_mem_alloc element cache. Require
BPF_F_NO_PREALLOC. Limit max_entries to 2^31. Free elements via
rhashtable_free_and_destroy().
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20260605-rhash-v7-4-5b8e05f8630d@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The KCOV selftest enables coverage by setting current->kcov_mode to
KCOV_MODE_TRACE_PC without installing a coverage area. If an interrupt
records coverage in that window, the access should fault and expose the
bug.
When building for QEMU raspi0 (Raspberry Pi Zero, ARMv6, CONFIG_CPU_V6K=y,
CONFIG_CURRENT_POINTER_IN_TPIDRURO=y) with GCC 13.3.0, the store that
enables the mode is removed. The generated kcov_init() code only stores
zero after the wait loop:
mrc 15, 0, r3, cr13, cr0, {3}
str r4, [r3, #2028]
where r4 is zero. There is no store of KCOV_MODE_TRACE_PC before the
loop, so the selftest reports success without exercising coverage.
Use WRITE_ONCE() for the temporary mode stores. With the same compiler
and config, kcov_init() contains the intended mode store:
mov r3, #2
mrc 15, 0, r2, cr13, cr0, {3}
str r3, [r2, #2028]
Now that the KCOV selftest is actually executed, it may expose KCOV
instrumentation issues depending on the kernel config. That is expected
for a selftest that was intended to catch coverage from interrupt paths.
Link: https://lore.kernel.org/20260526114715.38280-1-kmehltretter@gmail.com
Fixes: 6cd0dd934b03 ("kcov: Add interrupt handling self test")
Assisted-by: Codex:gpt-5
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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zap_vma_range() requires the owning mm's mmap_lock to be held.
Taking mmap_read_lock under arena->lock would AB-BA against
arena_vm_close() and arena_map_mmap(), both of which run with
mmap_write_lock held and then acquire arena->lock. Instead drop
arena->lock, mmget_not_zero() the vma's mm, take mmap_read_lock, and
re-resolve the vma via find_vma() since it may have been unmapped or
replaced while waiting.
Track processed vmls with a per-call generation in vml->zap_gen and
serialize zap_pages() callers with a new arena->zap_mutex so
concurrent callers on different uaddr ranges do not mark each other's
vmls processed before the zap is done.
Reported-by: David Hildenbrand <david@kernel.org>
Fixes: 317460317a02 ("bpf: Introduce bpf_arena.")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260528222014.38980-1-alexei.starovoitov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Refactor the newly introduced btf_scan_decl_tags() to improve
readability and maintainability. The current implementation uses a
manual if-else chain and a magic number offset to strip the "arg:"
prefix from declaration tags.
Replace the if-else logic with a table-driven approach using a static
const array. This separates the tag data from the scanning logic, making
the helper more extensible for future tags. Additionally, replace the
magic number '4' with a sizeof-based calculation on the prefix string to
ensure the offset remains synchronized with the search key.
Finally, optimize the loop by moving the is_global check to the top of
the block. This allows the verifier to fail-fast on static subprograms
without performing unnecessary BTF string and type lookups.
Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260603201822.770596-1-mattbobrowski@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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module_extend_max_pages() calls kvrealloc() internally and returns
-ENOMEM on allocation failure. The return value is never checked.
If the initial allocation fails, info->pages remains NULL and
info->max_pages remains 0. Subsequent calls to module_get_next_page()
will attempt to dynamically grow the array by calling
module_extend_max_pages(info, 0) since info->used_pages is 0. This
results in kvrealloc(NULL, 0) returning ZERO_SIZE_PTR, which is treated
as a success, leading to a dereference of ZERO_SIZE_PTR and a kernel
oops.
Fix: add the missing error check after module_extend_max_pages() and
return immediately on failure. This matches the pattern used by every
other kvrealloc() caller in the module loading path.
Fixes: b1ae6dc41eaa ("module: add in-kernel support for decompressing")
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Andrii Kuchmenko <capyenglishlite@gmail.com>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
[Sami: Corrected the analysis in the commit message.]
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
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tmigr_handle_remote_cpu() skips timer_expire_remote() when cpu ==
smp_processor_id(), assuming the local softirq path already handled this
CPU's timers.
This assumption is wrong because jiffies can advance after the handling of
the CPU's global timers in run_timer_base(BASE_GLOBAL) and before
tmigr_handle_remote() evaluates the expiry times.
As a consequence a timer which expires after the CPU local timer wheel
advanced and becomes expired in the remote handling is ignored and the
callback is never invoked and removed from the timer wheel.
What's worse is that fetch_next_timer_interrupt_remote() keeps reporting it
as expired, and the event is re-queued with expires == now on each
iteration. The goto-again loop spins indefinitely.
Fix this by calling timer_expire_remote() unconditionally. That's minimal
overhead for the common case as __run_timer_base() returns immediately if
there is nothing to expire in the local wheel.
[ tglx: Amend change log and add a comment ]
Fixes: 7ee988770326 ("timers: Implement the hierarchical pull model")
Reported-by: Alon Kariv <alonka@amazon.com>
Signed-off-by: Amit Matityahu <amitmat@amazon.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260603170139.33628-1-amitmat@amazon.com
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Translating between a BPF-arena pointer and its kernel-side address is just
an add or subtract of the arena's kern_vm start. More such translations are
coming, so cache that start on scx_sched as @arena_kern_base at arena attach
and wrap both directions. Convert the existing open-coded subtraction in
scx_call_op_set_cpumask().
Signed-off-by: Tejun Heo <tj@kernel.org>
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It gives useful info on knowing which PMUs are reserved by this process.
Also add config which would be useful.
Testing cycles:
$ ./perf stat -e cycles &
$ cat /proc/`pidof perf`/fdinfo/3
pos: 0
flags: 02000002
mnt_id: 16
ino: 3081
perf_event_attr.type: 0
perf_event_attr.config: 0x0
perf_event_attr.config1: 0x0
perf_event_attr.config2: 0x0
perf_event_attr.config3: 0x0
perf_event_attr.config4: 0x0
Testing L1-dcache-load-misses:
$ ./perf stat -e L1-dcache-load-misses &
$ cat /proc/`pidof perf`/fdinfo/3
pos: 0
flags: 02000002
mnt_id: 16
ino: 1072
perf_event_attr.type: 3
perf_event_attr.config: 0x10000
perf_event_attr.config1: 0x0
perf_event_attr.config2: 0x0
perf_event_attr.config3: 0x0
perf_event_attr.config4: 0x0
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://patch.msgid.link/20260602181349.3969429-1-ctshao@google.com
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Add a read_snapshot() callback to struct clocksource which returns the
derived clocksource value while also providing the underlying hardware
counter reading and the related clocksource ID.
This allows ktime_get_snapshot_id() to populate new hw_cycles and hw_csid
fields in struct system_time_snapshot.
For clocksources that are derived from an underlying counter (e.g., Hyper-V
TSC page scales TSC to 10MHz, kvmclock scales TSC to 1GHz), this provides
atomic access to both the derived value needed for timekeeping
calculations, and the raw hardware counter needed by consumers like KVM's
master clock and the vmclock PTP driver.
[ tglx: Reworked it slightly ]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Assisted-by: Kiro:claude-opus-4.6-1m
Link: https://patch.msgid.link/20260526230635.136914-1-dwmw2@infradead.org
Link: https://patch.msgid.link/20260529195558.202568489@kernel.org
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Now that all prerequisites are in place add the final support for AUX
clocks in get_device_system_crosststamp(), which enables the PTP layer to
support hardware cross timestamps with a new IOTCL.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Arthur Kiyanovski <akiyano@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260529195558.097464513@kernel.org
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PTP device system crosstime stamps support only CLOCK_REALTIME, which is
meaningless for AUX clocks. The PTP core hands in the clock ID already, so
prepare the core code to honor it.
- Add a new sys_systime field to struct system_device_crosststamp which
aliases the sys_realtime field. Once all users are converted
sys_realtime can be removed.
- Prepare get_device_system_crosststamp() and the related code for it by
switching to sys_systime and providing the initial changes to utilize
different time keepers.
No functional change intended.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: David Woodhouse <dwmw@amazon.co.uk>
Tested-by: Arthur Kiyanovski <akiyano@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260529195557.846634842@kernel.org
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An upcoming extension to the PTP IOCTL requires to return the system counter
value and the clocksource ID to user space. get_device_system_crosststamp() has
this information already.
Extend struct system_device_crosststamp with a system_counterval_t member
and fill in the data.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: David Woodhouse <dwmw@amazon.co.uk>
Tested-by: Arthur Kiyanovski <akiyano@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260529195557.429406675@kernel.org
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Now that all users are converted it's possible to enable snapshotting of
CLOCK_AUX time. The underlying clocksource is the same as for all other
CLOCK variants.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Arthur Kiyanovski <akiyano@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260529195557.380601005@kernel.org
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All users are converted over to ktime_get_snapshot_id() and
system_time_snapshot::systime and ::monoraw.
Remove the leftovers.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: David Woodhouse <dwmw@amazon.co.uk>
Tested-by: Arthur Kiyanovski <akiyano@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260529195557.330029635@kernel.org
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Switch scx_bpf_kick_cid() from void to s32 so future cap enforcement can
surface failures. cid interface is introduced in this cycle and has no
external users, so the ABI change is safe. Subsequent patches will add
-EPERM returns when the calling sub-sched lacks the required cap on the
target cid.
v2: Return scx_cid_to_cpu()'s errno instead of -EINVAL. (Andrea)
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
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Add single-bit test and iterator over set cids in an scx_cmask.
v2: Bound scx_cmask_for_each_cid() to the active span. (sashiko AI)
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
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__scx_cmask_set(), __scx_cmask_contains() and __scx_cmask_word() take the
cmask first and the cid second. The kernel's bit and cpumask predicates put
the index first: test_bit(nr, addr), cpumask_test_cpu(cpu, mask). Reorder
the cmask helpers to (cid, mask) for consistency, ahead of new single-cid
ops added next. Mask-level ops (and/or/andnot/copy/subset/intersects) keep
(dst, src).
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
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syzbot triggered the following splat in remove_waiter() via
FUTEX_CMP_REQUEUE_PI:
KASAN: null-ptr-deref in range [0x0000000000000a88-0x0000000000000a8f]
class_raw_spinlock_constructor
remove_waiter+0x159/0x1200 kernel/locking/rtmutex.c:1561
rt_mutex_start_proxy_lock+0x103/0x120
futex_requeue+0x10e4/0x20d0
__x64_sys_futex+0x34f/0x4d0
task_blocks_on_rt_mutex() does not arm the waiter upon deadlock detection,
leaving waiter->task nil, where 3bfdc63936dd ("rtmutex: Use waiter::task instead
of current in remove_waiter()") made this fatal.
Furthermore, rt_mutex_start_proxy_lock() should not be calling into remove_waiter()
upon a successfully grabbing the rtmutex. 1a1fb985f2e2 ("futex: Handle early deadlock
return correctly"), moved the remove_waiter() out of __rt_mutex_start_proxy_lock()
(where 'ret' was only ever 0 or < 0) into the wrapper. Tighten this check to
account for try_to_take_rt_mutex().
Fixes: 3bfdc63936dd ("rtmutex: Use waiter::task instead of current in remove_waiter()")
Reported-by: syzbot+78147abe6c524f183ee9@syzkaller.appspotmail.com
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/all/69f114ac.050a0220.ac8b.0003.GAE@google.com/
Link: https://patch.msgid.link/20260507112913.1019537-1-dave@stgolabs.net
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To remove the fixed limit on the number of preserved files per session,
transition the file metadata serialization from a single contiguous
memory block to a chain of linked blocks.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-11-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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Currently, the number of LUO sessions is limited by a fixed number of
pre-allocated pages for serialization (16 pages, allowing for ~819
sessions).
This limitation is problematic if LUO is used to support things such as
systemd file descriptor store, and would be used not just as VM memory
but to save other states on the machine.
Remove this limit by transitioning to a linked-block approach for
session metadata serialization. Instead of a single contiguous block,
session metadata is now stored in a chain of 16-page blocks. Each block
starts with a header containing the physical address of the next block
and the number of session entries in the current block.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-10-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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Currently, luo_session_setup_outgoing() allocates the session block and
sets its physical address in the header immediately. With upcoming
dynamic block-based session management, this makes the first block
different from the rest. Move the allocation to where it is first needed.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-9-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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Introduce a linked-block serialization mechanism for state handover.
Previously, LUO used contiguous memory blocks for serializing sessions
and files, which imposed limits on the total number of items that could
be preserved across a live update.
This commit adds the infrastructure for a more flexible, block-based
approach where serialized data is stored in a chain of linked blocks.
This is a generic KHO serialization block infrastructure that can be
used by multiple subsystems.
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-8-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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Extract the logic for deserializing single entries for sessions into
separate helper functions. In preparation to a linked-block
serialization for sessions.
This is a pure code movement, no other changes intended.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-7-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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Extract the logic for deserializing single entries for files into
separate helper functions. In preparation to a linked-block
serialization for files.
This is a pure code movement, no other changes intended.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-6-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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Entirely remove the LUO FDT wrapper since the FDT only carries the
compatible string and the pointer to the centralized struct luo_ser.
Instead, register the struct luo_ser via the KHO raw subtree
API, placing the compatibility string inside the structure itself.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-5-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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Transition the LUO to ABI v2, which centralizes state management into a
single struct luo_ser header.
Previously, LUO state was spread across multiple FDT properties and
subnodes. ABI v2 simplifies this by placing all core state, including
the liveupdate number and physical addresses for sessions and FLB
headers into a centralized struct luo_ser.
Note that this change introduces a semantic difference: the sessions
and FLB serialization formats are no longer completely independent of
the core LUO. Their metadata (such as physical addresses for sessions
and FLB headers) is now coupled to and managed via the centralized
struct luo_ser.
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-4-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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Refactoring luo_session_retrieve_fd() to avoid mixing automated
cleanup-style guards with goto-based resource release, which is not
recommended under the Linux kernel coding style.
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-3-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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This improves type safety and aligns the in-memory file_set->count with
the serialized count type. It avoids potential truncation or sign
conversion mismatch issues.
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260603154402.468928-2-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
"One cpuset fix and a maintenance update, both low-risk:
- Fix cpuset partition CPU accounting under sibling CPU exclusion
that could produce wrong CPU assignments and trigger
scheduling-domain warnings. Includes selftests.
- Update an email address in MAINTAINERS"
* tag 'cgroup-for-7.1-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup/cpuset: Change Ridong's email
cgroup/cpuset: Add test cases for sibling CPU exclusion on partition update
cgroup/cpuset: Use effective_xcpus in partcmd_update add/del mask calculation
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext fixes from Tejun Heo:
"Two low-risk fixes:
- Drop a spurious warning that can fire during cgroup migration while
a sched_ext scheduler is loaded
- Fix a drgn-based debug script that broke after scheduler state
moved into a per-scheduler struct"
* tag 'sched_ext-for-7.1-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
sched_ext: Don't warn on NULL cgrp_moving_from in scx_cgroup_move_task()
tools/sched_ext: Fix scx_show_state per-scheduler state reads
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In debug_dma_sync_sg_for_device(), when iterating over a scatterlist,
the debug entry population mistakenly uses the head of the scatterlist
'sg' to fetch the physical address via sg_phys(), instead of using the
current iterator variable 's'.
This causes dma-debug to track the physical address of the very first
scatterlist entry for all subsequent entries in the list.
Fix this by passing the correct loop iterator 's' to sg_phys()
Fixes: 9d4f645a1fd49ee ("dma-debug: store a phys_addr_t in struct dma_debug_entry")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260603123708.1665-1-lirongqing@baidu.com
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Tracepoint handlers no longer run with preemption disabled by default
since a46023d5616 ("tracing: Guard __DECLARE_TRACE() use of
__DO_TRACE_CALL() with SRCU-fast"), the opid monitor should now count 1
in the preemption count as preemption disabled.
Change the rule for preempt_off to preempt > 0.
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260601153840.124372-11-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
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Hybrid automata monitors may start timers, depending on the model, these
may remain active on an exiting task and cause false positives or even
access freed memory.
Add an enable/disable hook in the HA code, currently only populated by
the per-task handler for registration and deregistration.
This hooks to the sched_process_exit event and ensures the timer is
stopped for every exiting task. The handler is enabled automatically but
may be disabled, for instance if the monitor uses the event for another
purpose (but should still manually ensure timers are stopped).
Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type")
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260601153840.124372-8-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
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The attributes variables extracted from syscalls in the helper are both
defined with the __user specifier although only the actual pointer to
user data should be marked.
Remove the __user specifier from attr.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202604150820.Ny143u6X-lkp@intel.com
Fixes: b133207deb72 ("rv: Add nomiss deadline monitor")
Reviewed-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260601153840.124372-2-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
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When the FUTEX_ROBUST_UNLOCK mechanism is used for unlocking (PI-)futexes,
then the unlock sequence in user space looks like this:
1) robust_list_set_op_pending(mutex);
2) robust_list_remove(mutex);
lval = gettid();
3) if (atomic_try_cmpxchg(&mutex->lock, lval, 0))
4) robust_list_clear_op_pending();
else
5) sys_futex(OP | FUTEX_ROBUST_UNLOCK, ....);
That still leaves a minimal race window between #3 and #4 where the mutex
could be acquired by some other task, which observes that it is the last
user and:
1) unmaps the mutex memory
2) maps a different file, which ends up covering the same address
When then the original task exits before reaching #5 then the kernel robust
list handling observes the pending op entry and tries to fix up user space.
In case that the newly mapped data contains the TID of the exiting thread
at the address of the mutex/futex the kernel will set the owner died bit in
that memory and therefore corrupt unrelated data.
On X86 this boils down to this simplified assembly sequence:
mov %esi,%eax // Load TID into EAX
xor %ecx,%ecx // Set ECX to 0
#3 lock cmpxchg %ecx,(%rdi) // Try the TID -> 0 transition
.Lstart:
jnz .Lend
#4 movq %rcx,(%rdx) // Clear list_op_pending
.Lend:
If the cmpxchg() succeeds and the task is interrupted before it can clear
list_op_pending in the robust list head (#4) and the task crashes in a
signal handler or gets killed then it ends up in do_exit() and subsequently
in the robust list handling, which then might run into the unmap/map issue
described above.
This is only relevant when user space was interrupted and a signal is
pending. The fix-up has to be done before signal delivery is attempted
because:
1) The signal might be fatal so get_signal() ends up in do_exit()
2) The signal handler might crash or the task is killed before returning
from the handler. At that point the instruction pointer in pt_regs is
not longer the instruction pointer of the initially interrupted unlock
sequence.
The right place to handle this is in __exit_to_user_mode_loop() before
invoking arch_do_signal_or_restart() as this covers obviously both
scenarios.
As this is only relevant when the task was interrupted in user space, this
is tied to RSEQ and the generic entry code as RSEQ keeps track of user
space interrupts unconditionally even if the task does not have a RSEQ
region installed. That makes the decision very lightweight:
if (current->rseq.user_irq && within(regs, csr->unlock_ip_range))
futex_fixup_robust_unlock(regs, csr);
futex_fixup_robust_unlock() then invokes a architecture specific function
to return the pending op pointer or NULL. The function evaluates the
register content to decide whether the pending ops pointer in the robust
list head needs to be cleared.
Assuming the above unlock sequence, then on x86 this decision is the
trivial evaluation of the zero flag:
return regs->eflags & X86_EFLAGS_ZF ? regs->dx : NULL;
Other architectures might need to do more complex evaluations due to LLSC,
but the approach is valid in general. The size of the pointer is determined
from the matching range struct, which covers both 32-bit and 64-bit builds
including COMPAT.
The unlock sequence is going to be placed in the VDSO so that the kernel
can keep everything synchronized, especially the register usage. The
resulting code sequence for user space is:
if (__vdso_futex_robust_list$SZ_try_unlock(lock, tid, &pending_op) != tid)
err = sys_futex($OP | FUTEX_ROBUST_UNLOCK,....);
Both the VDSO unlock and the kernel side unlock ensure that the pending_op
pointer is always cleared when the lock becomes unlocked.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://patch.msgid.link/20260602090535.773669210@kernel.org
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There will be a VDSO function to unlock robust futexes in user space. The
unlock sequence is racy vs. clearing the list_pending_op pointer in the
tasks robust list head. To plug this race the kernel needs to know the
instruction window. As the VDSO is per MM the addresses are stored in
mm_struct::futex.
Architectures which implement support for this have to update these
addresses when the VDSO is (re)mapped and indicate the pending op pointer
size which is matching the IP.
Arguably this could be resolved by chasing mm->context->vdso->image, but
that's architecture specific and requires to touch quite some cache
lines. Having it in mm::futex reduces the cache line impact and avoids
having yet another set of architecture specific functionality.
To support multi size robust list applications (gaming) this provides two
ranges when COMPAT is enabled.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://patch.msgid.link/20260602090535.718926819@kernel.org
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Unlocking robust non-PI futexes happens in user space with the following
sequence:
1) robust_list_set_op_pending(mutex);
2) robust_list_remove(mutex);
lval = 0;
3) lval = atomic_xchg(lock, lval);
4) if (lval & WAITERS)
5) sys_futex(WAKE,....);
6) robust_list_clear_op_pending();
That opens a window between #3 and #6 where the mutex could be acquired by
some other task which observes that it is the last user and:
A) unmaps the mutex memory
B) maps a different file, which ends up covering the same address
When the original task exits before reaching #6 then the kernel robust list
handling observes the pending op entry and tries to fix up user space.
In case that the newly mapped data contains the TID of the exiting thread
at the address of the mutex/futex the kernel will set the owner died bit in
that memory and therefore corrupting unrelated data.
PI futexes have a similar problem both for the non-contented user space
unlock and the in kernel unlock:
1) robust_list_set_op_pending(mutex);
2) robust_list_remove(mutex);
lval = gettid();
3) if (!atomic_try_cmpxchg(lock, lval, 0))
4) sys_futex(UNLOCK_PI,....);
5) robust_list_clear_op_pending();
Address the first part of the problem where the futexes have waiters and
need to enter the kernel anyway. Add a new FUTEX_ROBUST_UNLOCK flag, which
is valid for the sys_futex() FUTEX_UNLOCK_PI, FUTEX_WAKE, FUTEX_WAKE_BITSET
operations.
This deliberately omits FUTEX_WAKE_OP from this treatment as it's unclear
whether this is needed and there is no usage of it in glibc either to
investigate.
For the futex2 syscall family this needs to be implemented with a new
syscall.
The sys_futex() case [ab]uses the @uaddr2 argument to hand the pointer to
robust_list_head::list_pending_op into the kernel. This argument is only
evaluated when the FUTEX_ROBUST_UNLOCK bit is set and is therefore backward
compatible.
This is an explicit argument to avoid the lookup of the robust list pointer
and retrieving the pending op pointer from there. User space has the
pointer already available so it can just put it into the @uaddr2
argument. Aside of that this allows the usage of multiple robust lists in
the future without any changes to the internal functions as they just operate
on the provided pointer.
This requires a second flag FUTEX_ROBUST_LIST32 which indicates that the
robust list pointer points to an u32 and not to an u64. This is required
for two reasons:
1) sys_futex() has no compat variant
2) The gaming emulators use both both 64-bit and compat 32-bit robust
lists in the same 64-bit application
As a consequence 32-bit applications have to set this flag unconditionally
so they can run on a 64-bit kernel in compat mode unmodified. 32-bit
kernels return an error code when the flag is not set. 64-bit kernels will
happily clear the full 64 bits if user space fails to set it.
In case of FUTEX_UNLOCK_PI this clears the robust list pending op when the
unlock succeeded. In case of errors, the user space value is still locked
by the caller and therefore the above cannot happen.
In case of FUTEX_WAKE* this does the unlock of the futex in the kernel and
clears the robust list pending op when the unlock was successful. If not,
the user space value is still locked and user space has to deal with the
returned error. That means that the unlocking of non-PI robust futexes has
to use the same try_cmpxchg() unlock scheme as PI futexes.
If the clearing of the pending list op fails (fault) then the kernel clears
the registered robust list pointer if it matches to prevent that exit()
will try to handle invalid data. That's a valid paranoid decision because
the robust list head sits usually in the TLS and if the TLS is not longer
accessible then the chance for fixing up the resulting mess is very close
to zero.
The problem of non-contended unlocks still exists and will be addressed
separately.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://patch.msgid.link/20260602090535.670514505@kernel.org
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The marker for PI futexes in the robust list is a hardcoded 0x1 which lacks
any sensible form of documentation.
Provide proper defines for the bit and the mask and fix up the usage
sites. Thereby convert the boolean pi argument into a modifier argument,
which allows new modifier bits to be trivially added and conveyed.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://patch.msgid.link/20260602090535.458758556@kernel.org
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Having all these members in mm_struct along with the required #ifdeffery is
annoying, does not allow efficient initializing of the data with
memset() and makes extending it tedious.
Move it into a data structure and fix up all usage sites.
The extra struct for the private hash is intentional to make integration of
other conditional mechanisms easier in terms of initialization and separation.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260602090535.407756793@kernel.org
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Nothing fails there. Mop up the leftovers of the early version of this,
which did an allocation.
While at it clean up the stubs and the #ifdef comments to make the header
file readable.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260602090535.356789395@kernel.org
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Having all these members in task_struct along with the required #ifdeffery
is annoying, does not allow efficient initializing of the data with
memset() and makes extending it tedious.
Move it into a data structure and fix up all usage sites.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://patch.msgid.link/20260602090535.308220888@kernel.org
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irqdesc_lock uses __DEFINE_UNLOCK_GUARD() directly with a custom
constructor that can set .lock to NULL.
In preparation for removing the NULL check from __DEFINE_UNLOCK_GUARD(),
move the NULL check into the irqdesc_lock unlock expression, making the
NULL handling explicit at the call site.
No functional change.
Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/ab457810653e4356e29b2d74ba616478bd9328ad.1780064327.git.d@ilvokhin.com
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In dma_direct_map_sg(), the case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE
incorrectly used 'break' instead of falling through to MAP_NONE.
As a result, segments traversing the host bridge skipped the required
dma_direct_map_phys() call entirely, leaving sg->dma_address
uninitialized and leading to DMA failures. Fix this by using
'fallthrough;'.
Fixes: a25e7962db0d79 ("PCI/P2PDMA: Refactor the p2pdma mapping helpers")
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260603013723.2439-1-lirongqing@baidu.com
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The buf pointer was kmalloc_array()'d immediately after the parent
struct allocation, with the count (granule, validated to 1..1024 by
the ioctl) trivially available beforehand. Move buf to the struct
tail as a flexible array member and fold the two allocations into a
single kzalloc_flex(), dropping the kfree(params->buf) in both the
prepare error path and unprepare.
Add __counted_by for extra runtime analysis.
Assisted-by: Claude:Opus-4.7
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Qinxin Xia <xiaqinxin@huawei.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260603031758.290538-1-rosenp@gmail.com
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Patch series "mm: misc cleanups from __GFP_UNMAPPED series".
In v2 of the __GFP_UNMAPPED series [0], we realised that some of the
patches could potentially be merged as independent cleanups.
These are all independent of one another, if you think some are useful
cleanups and others are pointless churn, it should be fine to just pick
whatever subset you prefer.
No functional change intended.
This patch (of 4):
There are a couple of places that iterate over the freelists with
awareness of the data structures' layout.
It seems ideally, code outside of mm should not be aware of the page
allocator's freelists at all. But, this patch just doesn't hide them
completely, it's just a meek incremental step in that direction: provide a
macro to iterate over it without needing to be aware of the actual struct
fields.
Link: https://lore.kernel.org/20260513-page_alloc-unmapped-prep-v1-0-dacdf5402be8@google.com
Link: https://lore.kernel.org/20260513-page_alloc-unmapped-prep-v1-1-dacdf5402be8@google.com
Link: https://lore.kernel.org/all/20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@google.com/ [0]
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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A WARN fires when systemd's user manager writes "+cpu +memory +pids" to
its own subtree_control while a sched_ext scheduler is loaded:
WARNING: at kernel/sched/ext.c:3227 scx_cgroup_move_task+0xa8/0xb0
scx_cgroup_move_task+0xa8/0xb0
sched_move_task+0x134/0x290
cpu_cgroup_attach+0x39/0x70
cgroup_migrate_execute+0x37d/0x450
cgroup_update_dfl_csses+0x1e3/0x270
cgroup_subtree_control_write+0x3e7/0x440
scx_cgroup_can_attach() arms cgrp_moving_from only when a task's cpu
cgroup changes. It can still be NULL when scx_cgroup_move_task() runs,
through this sequence:
Step Result
--------------------------------- ----------------------------------
1. cpu enabled on cgroup G cpu css = A
2. cpu toggled off then on for G A killed, B created (same cgroup)
3. an exiting task keeps A alive migration skips it, A now stale
4. +memory migrates G stale A vs current B pulls cpu in
5. cpu attach runs for all tasks hits a live, cpu-unchanged task
6. scx_cgroup_move_task() on it cgrp_moving_from NULL -> WARN
The mismatch is that scx_cgroup_can_attach() keys on cgroup identity
while migration drives the move on css identity, so a NULL cgrp_moving_from
here is a legitimate css-only migration, not a missing prep.
The call is already gated on cgrp_moving_from, so just drop the warning.
ops.cgroup_prep_move() and ops.cgroup_move() stay paired.
Fixes: 819513666966 ("sched_ext: Add cgroup support")
Cc: stable@vger.kernel.org # v6.12+
Reported-by: Matt Fleming <mfleming@cloudflare.com>
Closes: https://lore.kernel.org/all/20260601124156.2205704-1-mfleming@cloudflare.com/
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
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self-deadlock
When FUTEX_CMP_REQUEUE_PI requeues a non-top waiter that already owns the
target PI futex, task_blocks_on_rt_mutex() returns -EDEADLK before setting
waiter->task.
The subsequent remove_waiter() in rt_mutex_start_proxy_lock() dereferences
the NULL waiter->task, causing a kernel crash.
Add a self-deadlock check for non-top waiters before calling
rt_mutex_start_proxy_lock(), analogous to the top-waiter check in
futex_lock_pi_atomic().
Fixes: 3bfdc63936dd4773109b7b8c280c0f3b5ae7d349 ("rtmutex: Use waiter::task instead of current in remove_waiter()")
Signed-off-by: Ji'an Zhou <eilaimemedsnaimel@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
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This Kconfig symbol is not used anymore, remove it.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260519-vdso-generic_time_vsyscal-v1-3-5c2a5905d5f5@linutronix.de
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The level_list array is allocated separately right after the parent
struct. The size of the array is already known.
Move level_list to the struct tail as a flexible array member and fold the
two allocations into a single kzalloc_flex().
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Assisted-by: Claude:Opus-4.7
Link: https://patch.msgid.link/20260522231618.41622-1-rosenp@gmail.com
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NOHZ_FULL CPUs global timers are guaranteed to be handled by the timekeeper
CPU, which never stops its tick and therefore remains active in the
hierarchy.
But since the introduction of per-capacity hierarchies, this guarantee is
broken because the timekeeper may not belong to the same hierarchy as all
the NOHZ_FULL CPUs.
Fix it with simply turning off capacity awareness when NOHZ_FULL is
running and force a single hierarchy. NOHZ_FULL is not exactly optimized
powerwise anyway.
Fixes: 098cbaad8e57 ("timers/migration: Split per-capacity hierarchies")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260519220926.63437-3-frederic@kernel.org
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