Commit cc3bad11de6e ("printk_ringbuffer: Fix check of valid data
size when blk_lpos overflows") added sanity checking to get_data()
to avoid returning data of illegal sizes (too large or too small).
It uses the helper function data_check_size() for the check.
However, data_check_size() expects the size of the data, not the
size of the data block. get_data() is providing the size of the
data block. This means that if the data size (text_buf_size) is
at or near the maximum legal size:

sizeof(prb_data_block) + text_buf_size == DATA_SIZE(data_ring) / 2

data_check_size() will report failure because it adds
sizeof(prb_data_block) to the provided size. The sanity check in
get_data() is counting the data block header twice. The result is
that the reader fails to read the legal record.

Since get_data() subtracts the data block header size before returning,
move the sanity check to after the subtraction.

Luckily printk() is not vulnerable to this problem because
truncate_msg() limits printk-messages to 1/4 of the ringbuffer.
Indeed, by adjusting the printk_ringbuffer KUnit test, which does not
use printk() and its truncate_msg() check, it is easy to see that the
reader fails and the WARN_ON is triggered.

Fixes: cc3bad11de6e ("printk_ringbuffer: Fix check of valid data size when blk_lpos overflows")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20260326133809.8045-1-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>

The _DESCS_COUNT macro currently uses 1U (32-bit unsigned) instead of
1UL (unsigned long), which breaks the intended overflow testing design
on 64-bit systems.

Problem Analysis:
----------------
The printk_ringbuffer uses a deliberate design choice to initialize
descriptor IDs near the maximum 62-bit value to trigger overflow early
in the system's lifetime. This is documented in printk_ringbuffer.h:

"initial values are chosen that map to the correct initial array
indexes, but will result in overflows soon."

The DESC0_ID macro calculates:
DESC0_ID(ct_bits) = DESC_ID(-(_DESCS_COUNT(ct_bits) + 1))

On 64-bit systems with typical configuration (descbits=16):
- Current buggy behavior: DESC0_ID = 0xfffeffff
- Expected behavior: DESC0_ID = 0x3ffffffffffeffff

The buggy version only uses 32 bits, which means:
1. The initial ID is nowhere near 2^62
2. It would take ~140 trillion wraps to trigger 62-bit overflow
3. The overflow handling code is never tested in practice

Root Cause:
----------
The issue is in this line:
#define _DESCS_COUNT(ct_bits) (1U << (ct_bits))

When _DESCS_COUNT(16) is calculated:
1U << 16 = 0x10000 (32-bit value)
-(0x10000 + 1) = -0x10001 = 0xFFFEFFFF (32-bit two's complement)

On 64-bit systems, this 32-bit value doesn't get extended to create
the intended 62-bit ID near the maximum value.

Impact:
------
While index calculations still work correctly in the short term, this
bug has several implications:

1. Violates the design intention documented in the code
2. Overflow handling code paths remain untested
3. ABA detection code doesn't get exercised under overflow conditions
4. In extreme long-term running scenarios (though unlikely), could
potentially cause issues when ID actually reaches 2^62

Verification:
------------
Tested on ARM64 system with CONFIG_LOG_BUF_SHIFT=20 (descbits=15):
- Before fix: DESC0_ID(16) = 0xfffeffff
- After fix: DESC0_ID(16) = 0x3fffffffffff7fff

The fix aligns _DESCS_COUNT with _DATA_SIZE, which already correctly
uses 1UL:
#define _DATA_SIZE(sz_bits) (1UL << (sz_bits))

Signed-off-by: feng.zhou <realsummitzhou@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20260202094140.9518-1-realsummitzhou@gmail.com
Signed-off-by: Petr Mladek <pmladek@suse.com>

Pull printk updates from Petr Mladek:

- Check all mandatory callbacks when registering nbcon consoles

- Fix some compiler warnings

* tag 'printk-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
vsnprintf: drop __printf() attributes on binary printing functions
printf: convert test_hashed into macro
printk: nbcon: Check for device_{lock,unlock} callbacks

Pull slab updates from Vlastimil Babka:

- The percpu sheaves caching layer was introduced as opt-in in 6.18 and
now we enable it for all caches and remove the previous cpu (partial)
slab caching mechanism.

Besides the lower locking overhead and much more likely fastpath when
freeing, this removes the rather complicated code related to the cpu
slab lockless fastpaths (using this_cpu_try_cmpxchg128/64) and all
its complications for PREEMPT_RT or kmalloc_nolock().

The lockless slab freelist+counters update operation using
try_cmpxchg128/64 remains and is crucial for freeing remote NUMA
objects, and to allow flushing objects from sheaves to slabs mostly
without the node list_lock (Vlastimil Babka)

- Eliminate slabobj_ext metadata overhead when possible. Instead of
using kmalloc() to allocate the array for memcg and/or allocation
profiling tag pointers, use leftover space in a slab or per-object
padding due to alignment (Harry Yoo)

- Various followup improvements to the above (Hao Li)

* tag 'slab-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (39 commits)
slub: let need_slab_obj_exts() return false if SLAB_NO_OBJ_EXT is set
mm/slab: only allow SLAB_OBJ_EXT_IN_OBJ for unmergeable caches
mm/slab: place slabobj_ext metadata in unused space within s->size
mm/slab: move [__]ksize and slab_ksize() to mm/slub.c
mm/slab: save memory by allocating slabobj_ext array from leftover
mm/memcontrol,alloc_tag: handle slabobj_ext access under KASAN poison
mm/slab: use stride to access slabobj_ext
mm/slab: abstract slabobj_ext access via new slab_obj_ext() helper
ext4: specify the free pointer offset for ext4_inode_cache
mm/slab: allow specifying free pointer offset when using constructor
mm/slab: use unsigned long for orig_size to ensure proper metadata align
slub: clarify object field layout comments
mm/slab: avoid allocating slabobj_ext array from its own slab
slub: avoid list_lock contention from __refill_objects_any()
mm/slub: cleanup and repurpose some stat items
mm/slub: remove DEACTIVATE_TO_* stat items
slab: remove frozen slab checks from __slab_free()
slab: update overview comments
slab: refill sheaves from all nodes
slab: remove unused PREEMPT_RT specific macros
...

Pull Kbuild/Kconfig updates from Nathan Chancellor:
"Kbuild:

- Drop '*_probe' pattern from modpost section check allowlist, which
hid legitimate warnings (Johan Hovold)

- Disable -Wtype-limits altogether, instead of enabling at W=2
(Vincent Mailhol)

- Improve UAPI testing to skip testing headers that require a libc
when CONFIG_CC_CAN_LINK is not set, opening up testing of headers
with no libc dependencies to more environments (Thomas Weißschuh)

- Update gendwarfksyms documentation with required dependencies
(Jihan LIN)

- Reject invalid LLVM= values to avoid unintentionally falling back
to system toolchain (Thomas Weißschuh)

- Add a script to help run the kernel build process in a container
for consistent environments and testing (Guillaume Tucker)

- Simplify kallsyms by getting rid of the relative base (Ard
Biesheuvel)

- Performance and usability improvements to scripts/make_fit.py
(Simon Glass)

- Minor various clean ups and fixes

Kconfig:

- Move XPM icons to individual files, clearing up GTK deprecation
warnings (Rostislav Krasny)

- Support

depends on FOO if BAR

as syntactic sugar for

depends on FOO || !BAR

(Nicolas Pitre, Graham Roff)

- Refactor merge_config.sh to use awk over shell/sed/grep,
dramatically speeding up processing large number of config
fragments (Anders Roxell, Mikko Rapeli)"

* tag 'kbuild-7.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (39 commits)
kbuild: remove dependency of run-command on config
scripts/make_fit: Compress dtbs in parallel
scripts/make_fit: Support a few more parallel compressors
kbuild: Support a FIT_EXTRA_ARGS environment variable
scripts/make_fit: Move dtb processing into a function
scripts/make_fit: Support an initial ramdisk
scripts/make_fit: Speed up operation
rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option
MAINTAINERS: Add scripts/install.sh into Kbuild entry
modpost: Amend ppc64 save/restfpr symnames for -Os build
MIPS: tools: relocs: Ship a definition of R_MIPS_PC32
streamline_config.pl: remove superfluous exclamation mark
kbuild: dummy-tools: Add python3
scripts: kconfig: merge_config.sh: warn on duplicate input files
scripts: kconfig: merge_config.sh: use awk in checks too
scripts: kconfig: merge_config.sh: refactor from shell/sed/grep to awk
kallsyms: Get rid of kallsyms relative base
mips: Add support for PC32 relocations in vmlinux
Documentation: dev-tools: add container.rst page
scripts: add tool to run containerized builds
...

Merge series "slab: replace cpu (partial) slabs with sheaves".

The percpu sheaves caching layer was introduced as opt-in but the goal
was to eventually move all caches to them. This is the next step,
enabling sheaves for all caches (except the two bootstrap ones) and then
removing the per cpu (partial) slabs and lots of associated code.

Besides the lower locking overhead and much more likely fastpath when
freeing, this removes the rather complicated code related to the cpu
slab lockless fastpaths (using this_cpu_try_cmpxchg128/64) and all its
complications for PREEMPT_RT or kmalloc_nolock().

The lockless slab freelist+counters update operation using
try_cmpxchg128/64 remains and is crucial for freeing remote NUMA objects
and to allow flushing objects from sheaves to slabs mostly without the
node list_lock.

Link: https://lore.kernel.org/all/20260123-sheaves-for-all-v4-0-041323d506f7@suse.cz/

Pull printk fix from Petr Mladek:

- Prevent softlockup by restoring IRQs in atomic flush after each
record

* tag 'printk-for-6.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk/nbcon: Restore IRQ in atomic flush after each emitted record

The printf() format attributes are applied inconsistently for the binary
printf helpers, which causes warnings for the bpf_trace code using
them from functions that pass down format strings:

kernel/trace/bpf_trace.c: In function '____bpf_trace_printk':
kernel/trace/bpf_trace.c:377:9: error: function '____bpf_trace_printk' might be a candidate for 'gnu_printf' format attribute [-Werror=suggest-attribute=format]
377 | ret = bstr_printf(data.buf, MAX_BPRINTF_BUF, fmt, data.bin_args);
| ^~~

This can be addressed either by annotating all five callers in bpf code,
or by removing the annotations on the callees that were added by Andy
Shevchenko last year.

As Alexei Starovoitov points out, there are no callers in C code that
would benefit from the __printf attributes, the only users are in BPF
code or in the do_trace_printk() helper that already checks the arguments.

Drop all three of these annotations, reverting the earlierl commits that
added these, in order to get a clean build with -Wsuggest-attribute=format.

Fixes: 6b2c1e30ad68 ("seq_file: Mark binary printing functions with __printf() attribute")
Fixes: 7bf819aa992f ("vsnprintf: Mark binary printing functions with __printf() attribute")
Link: https://lore.kernel.org/all/CAADnVQK3eZp3yp35OUx8j1UBsQFhgsn5-4VReqAJ=68PaaKYmg@mail.gmail.com/
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512061640.9hKTnB8p-lkp@intel.com/
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Acked-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Petr Mladek <pmladek@suse.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260204132643.1302967-1-arnd@kernel.org
Signed-off-by: Petr Mladek <pmladek@suse.com>

Pull sched_ext updates from Tejun Heo:

- Move C example schedulers back from the external scx repo to
tools/sched_ext as the authoritative source. scx_userland and
scx_pair are returning while scx_sdt (BPF arena-based task data
management) is new. These schedulers will be dropped from the
external repo.

- Improve error reporting by adding scx_bpf_error() calls when DSQ
creation fails across all in-tree schedulers

- Avoid redundant irq_work_queue() calls in destroy_dsq() by only
queueing when llist_add() indicates an empty list

- Fix flaky init_enable_count selftest by properly synchronizing
pre-forked children using a pipe instead of sleep()

* tag 'sched_ext-for-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
selftests/sched_ext: Fix init_enable_count flakiness
tools/sched_ext: Fix data header access during free in scx_sdt
tools/sched_ext: Add error logging for dsq creation failures in remaining schedulers
tools/sched_ext: add arena based scheduler
tools/sched_ext: add scx_pair scheduler
tools/sched_ext: add scx_userland scheduler
sched_ext: Add error logging for dsq creation failures
sched_ext: Avoid multiple irq_work_queue() calls in destroy_dsq()

The run-command target does not always require a kernel configuration
to be present.

Drop the dependency so it can be executed without one.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://patch.msgid.link/20260205-kbuild-run-command-v1-1-b8cbbc3db270@weissschuh.net
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

SLAB_NO_OBJ_EXT is set for boot caches, but need_slab_obj_exts() doesn't
check this flag. We should return false unconditionally when
SLAB_NO_OBJ_EXT is set.

Signed-off-by: Hao Li <hao.li@linux.dev>
Acked-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260205120709.425719-1-hao.li@linux.dev
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Kernel test robot has reported a regression in the patch "slab: refill
sheaves from all nodes". When taken in isolation like this, there is
indeed a tradeoff - we prefer to use remote objects prior to allocating
new local slabs. It is replicating a behavior that existed before
sheaves for replenishing cpu (partial) slabs - now called
get_from_any_partial() to allocate a single object.

So the possibility of allocating remote objects is intended even if
remote accesses are then slower. But the profiles in the report also
suggested a contention on the list_lock spinlock. And that's something
we can try to avoid without much tradeoff - if someone else has the
spin_lock, it's more likely they are allocating from the node than
freeing to it, so we can skip it even if it means allocating a new local
slab - contributing to that lock's contention isn't worth it. It should
not result in partial slabs accumulating on the remote node.

Thus add an allow_spin parameter to __refill_objects_node() and
get_partial_node_bulk() to make the attempts from __refill_objects_any()
use only a trylock.

Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202601132136.77efd6d7-lkp@intel.com
Link: https://patch.msgid.link/20260129-b4-refill_any_trylock-v1-1-de7420b25840@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Pull xfs fixes from Carlos Maiolino:
"Just a few obvious fixes and some 'cosmetic' changes"

* tag 'xfs-fixes-6.19-rc6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: set max_agbno to allow sparse alloc of last full inode chunk
xfs: Fix xfs_grow_last_rtg()
xfs: improve the assert at the top of xfs_log_cover
xfs: fix an overly long line in xfs_rtgroup_calc_geometry
xfs: mark __xfs_rtgroup_extents static
xfs: Fix the return value of xfs_rtcopy_summary()
xfs: fix memory leak in xfs_growfs_check_rtgeom()

The commit d5d399efff6577 ("printk/nbcon: Release nbcon consoles ownership
in atomic flush after each emitted record") prevented stall of a CPU
which lost nbcon console ownership because another CPU entered
an emergency flush.

But there is still the problem that the CPU doing the emergency flush
might cause a stall on its own.

Let's go even further and restore IRQ in the atomic flush after
each emitted record.

It is not a complete solution. The interrupts and/or scheduling might
still be blocked when the emergency atomic flush was called with
IRQs and/or scheduling disabled. But it should remove the following
lockup:

mlx5_core 0000:03:00.0: Shutdown was called
kvm: exiting hardware virtualization
arm-smmu-v3 arm-smmu-v3.10.auto: CMD_SYNC timeout at 0x00000103 [hwprod 0x00000104, hwcons 0x00000102]
smp: csd: Detected non-responsive CSD lock (#1) on CPU#4, waiting 5000000032 ns for CPU#00 do_nothing (kernel/smp.c:1057)
smp: csd: CSD lock (#1) unresponsive.
[...]
Call trace:
pl011_console_write_atomic (./arch/arm64/include/asm/vdso/processor.h:12 drivers/tty/serial/amba-pl011.c:2540) (P)
nbcon_emit_next_record (kernel/printk/nbcon.c:1049)
__nbcon_atomic_flush_pending_con (kernel/printk/nbcon.c:1517)
__nbcon_atomic_flush_pending.llvm.15488114865160659019 (./arch/arm64/include/asm/alternative-macros.h:254 ./arch/arm64/include/asm/cpufeature.h:808 ./arch/arm64/include/asm/irqflags.h:192 kernel/printk/nbcon.c:1562 kernel/printk/nbcon.c:1612)
nbcon_atomic_flush_pending (kernel/printk/nbcon.c:1629)
printk_kthreads_shutdown (kernel/printk/printk.c:?)
syscore_shutdown (drivers/base/syscore.c:120)
kernel_kexec (kernel/kexec_core.c:1045)
__arm64_sys_reboot (kernel/reboot.c:794 kernel/reboot.c:722 kernel/reboot.c:722)
invoke_syscall (arch/arm64/kernel/syscall.c:50)
el0_svc_common.llvm.14158405452757855239 (arch/arm64/kernel/syscall.c:?)
do_el0_svc (arch/arm64/kernel/syscall.c:152)
el0_svc (./arch/arm64/include/asm/alternative-macros.h:254 ./arch/arm64/include/asm/cpufeature.h:808 ./arch/arm64/include/asm/irqflags.h:73 arch/arm64/kernel/entry-common.c:169 arch/arm64/kernel/entry-common.c:182 arch/arm64/kernel/entry-common.c:749)
el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:820)
el0t_64_sync (arch/arm64/kernel/entry.S:600)

In this case, nbcon_atomic_flush_pending() is called from
printk_kthreads_shutdown() with IRQs and scheduling enabled.

Note that __nbcon_atomic_flush_pending_con() is directly called also from
nbcon_device_release() where the disabled IRQs might break PREEMPT_RT
guarantees. But the atomic flush is called only in emergency or panic
situations where the latencies are irrelevant anyway.

An ultimate solution would be a touching of watchdogs. But it would hide
all problems. Let's do it later when anyone reports a stall which does
not have a better solution.

Closes: https://lore.kernel.org/r/sqwajvt7utnt463tzxgwu2yctyn5m6bjwrslsnupfexeml6hkd@v6sqmpbu3vvu
Tested-by: Breno Leitao <leitao@debian.org>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20251212124520.244483-1-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>

This allows the compiler to check the arguments against the __printf()
attribute on __test(). This produces better diagnostics when incorrect
inputs are passed.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512061600.89CKQ3ag-lkp@intel.com/
Signed-off-by: Tamir Duberstein <tamird@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260121-printf-kunit-printf-attr-v3-1-4144f337ec8b@kernel.org
Signed-off-by: Petr Mladek <pmladek@suse.com>

Pull cgroup updates from Tejun Heo:

- cpuset changes:

- Continue separating v1 and v2 implementations by moving more
v1-specific logic into cpuset-v1.c

- Improve partition handling. Sibling partitions are no longer
invalidated on cpuset.cpus conflict, cpuset.cpus changes no longer
fail in v2, and effective_xcpus computation is made consistent

- Fix partition effective CPUs overlap that caused a warning on
cpuset removal when sibling partitions shared CPUs

- Increase the maximum cgroup subsystem count from 16 to 32 to
accommodate future subsystem additions

- Misc cleanups and selftest improvements including switching to
css_is_online() helper, removing dead code and stale documentation
references, using lockdep_assert_cpuset_lock_held() consistently, and
adding polling helpers for asynchronously updated cgroup statistics

* tag 'cgroup-for-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits)
cpuset: fix overlap of partition effective CPUs
cgroup: increase maximum subsystem count from 16 to 32
cgroup: Remove stale cpu.rt.max reference from documentation
cpuset: replace direct lockdep_assert_held() with lockdep_assert_cpuset_lock_held()
cgroup/cpuset: Move the v1 empty cpus/mems check to cpuset1_validate_change()
cgroup/cpuset: Don't invalidate sibling partitions on cpuset.cpus conflict
cgroup/cpuset: Don't fail cpuset.cpus change in v2
cgroup/cpuset: Consistently compute effective_xcpus in update_cpumasks_hier()
cgroup/cpuset: Streamline rm_siblings_excl_cpus()
cpuset: remove dead code in cpuset-v1.c
cpuset: remove v1-specific code from generate_sched_domains
cpuset: separate generate_sched_domains for v1 and v2
cpuset: move update_domain_attr_tree to cpuset_v1.c
cpuset: add cpuset1_init helper for v1 initialization
cpuset: add cpuset1_online_css helper for v1-specific operations
cpuset: add lockdep_assert_cpuset_lock_held helper
cpuset: Remove unnecessary checks in rebuild_sched_domains_locked
cgroup: switch to css_is_online() helper
selftests: cgroup: Replace sleep with cg_read_key_long_poll() for waiting on nr_dying_descendants
selftests: cgroup: make test_memcg_sock robust against delayed sock stats
...

The init_enable_count test is flaky. The test forks 1024 children before
attaching the scheduler to verify that existing tasks get ops.init_task()
called. The children were using sleep(1) before exiting.

7900aa699c34 ("sched_ext: Fix cgroup exit ordering by moving sched_ext_free()
to finish_task_switch()") changed when tasks are removed from scx_tasks -
previously when the task_struct was freed, now immediately in
finish_task_switch() when the task dies.

Before the commit, pre-forked children would linger on scx_tasks until freed
regardless of when they exited, so the scheduler would always see them during
iteration. The sleep(1) was unnecessary. After the commit, children are
removed as soon as they die. The sleep(1) masks the problem in most cases but
the test becomes flaky depending on timing.

Fix by synchronizing properly using a pipe. All children block on read() and
the parent signals them to exit by closing the write end after attaching the
scheduler. The children are auto-reaped so there's no need to wait on them.

Reported-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Cc: David Vernet <void@manifault.com>
Cc: Andrea Righi <arighi@nvidia.com>
Cc: Changwoo Min <changwoo@igalia.com>
Cc: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

When there are 1500 device tree files it takes quite a while to compress
them. Do it in parallel.

Signed-off-by: Simon Glass <sjg@chromium.org>
Link: https://patch.msgid.link/20260106162738.2605574-7-sjg@chromium.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

While SLAB_OBJ_EXT_IN_OBJ allows to reduce memory overhead to account
slab objects, it prevents slab merging because merging can change
the metadata layout.

As pointed out Vlastimil Babka, disabling merging solely for this memory
optimization may not be a net win, because disabling slab merging tends
to increase overall memory usage.

Restrict SLAB_OBJ_EXT_IN_OBJ to caches that are already unmergeable for
other reasons (e.g., those with constructors or SLAB_TYPESAFE_BY_RCU).

Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260127103151.21883-3-harry.yoo@oracle.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

A number of stat items related to cpu slabs became unused, remove them.

Two of those were ALLOC_FASTPATH and FREE_FASTPATH. But instead of
removing those, use them instead of ALLOC_PCS and FREE_PCS, since
sheaves are the new (and only) fastpaths, Remove the recently added
_PCS variants instead.

Change where FREE_SLOWPATH is counted so that it only counts freeing of
objects by slab users that (for whatever reason) do not go to a percpu
sheaf, and not all (including internal) callers of __slab_free(). Thus
sheaf flushing (already counted by SHEAF_FLUSH) does not affect
FREE_SLOWPATH anymore. This matches how ALLOC_SLOWPATH doesn't count
sheaf refills (counted by SHEAF_REFILL).

Reviewed-by: Hao Li <hao.li@linux.dev>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Add a GPL-2.0 license identifier line for this file.

kmod.c was originally introduced in the kernel in February
of 1998 by Linus Torvalds - who was familiar with kernel
licensing at the time this was introduced.

Signed-off-by: Tim Bird <tim.bird@sony.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Sparse inode cluster allocation sets min/max agbno values to avoid
allocating an inode cluster that might map to an invalid inode
chunk. For example, we can't have an inode record mapped to agbno 0
or that extends past the end of a runt AG of misaligned size.

The initial calculation of max_agbno is unnecessarily conservative,
however. This has triggered a corner case allocation failure where a
small runt AG (i.e. 2063 blocks) is mostly full save for an extent
to the EOFS boundary: [2050,13]. max_agbno is set to 2048 in this
case, which happens to be the offset of the last possible valid
inode chunk in the AG. In practice, we should be able to allocate
the 4-block cluster at agbno 2052 to map to the parent inode record
at agbno 2048, but the max_agbno value precludes it.

Note that this can result in filesystem shutdown via dirty trans
cancel on stable kernels prior to commit 9eb775968b68 ("xfs: walk
all AGs if TRYLOCK passed to xfs_alloc_vextent_iterate_ags") because
the tail AG selection by the allocator sets t_highest_agno on the
transaction. If the inode allocator spins around and finds an inode
chunk with free inodes in an earlier AG, the subsequent dir name
creation path may still fail to allocate due to the AG restriction
and cancel.

To avoid this problem, update the max_agbno calculation to the agbno
prior to the last chunk aligned agbno in the AG. This is not
necessarily the last valid allocation target for a sparse chunk, but
since inode chunks (i.e. records) are chunk aligned and sparse
allocs are cluster sized/aligned, this allows the sb_spino_align
alignment restriction to take over and round down the max effective
agbno to within the last valid inode chunk in the AG.

Note that even though the allocator improvements in the
aforementioned commit seem to avoid this particular dirty trans
cancel situation, the max_agbno logic improvement still applies as
we should be able to allocate from an AG that has been appropriately
selected. The more important target for this patch however are
older/stable kernels prior to this allocator rework/improvement.

Cc: stable@vger.kernel.org # v4.2
Fixes: 56d1115c9bc7 ("xfs: allocate sparse inode chunks on full chunk allocation failure")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Pull printk updates from Petr Mladek:

- Allow creaing nbcon console drivers with an unsafe write_atomic()
callback that can only be called by the final nbcon_atomic_flush_unsafe().
Otherwise, the driver would rely on the kthread.

It is going to be used as the-best-effort approach for an
experimental nbcon netconsole driver, see

https://lore.kernel.org/r/20251121-nbcon-v1-2-503d17b2b4af@debian.org

Note that a safe .write_atomic() callback is supposed to work in NMI
context. But some networking drivers are not safe even in IRQ
context:

https://lore.kernel.org/r/oc46gdpmmlly5o44obvmoatfqo5bhpgv7pabpvb6sjuqioymcg@gjsma3ghoz35

In an ideal world, all networking drivers would be fixed first and
the atomic flush would be blocked only in NMI context. But it brings
the question how reliable networking drivers are when the system is
in a bad state. They might block flushing more reliable serial
consoles which are more suitable for serious debugging anyway.

- Allow to use the last 4 bytes of the printk ring buffer.

- Prevent queuing IRQ work and block printk kthreads when consoles are
suspended. Otherwise, they create non-necessary churn or even block
the suspend.

- Release console_lock() between each record in the kthread used for
legacy consoles on RT. It might significantly speed up the boot.

- Release nbcon context between each record in the atomic flush. It
prevents stalls of the related printk kthread after it has lost the
ownership in the middle of a record

- Add support for NBCON consoles into KDB

- Add %ptsP modifier for printing struct timespec64 and use it where
possible

- Misc code clean up

* tag 'printk-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (48 commits)
printk: Use console_is_usable on console_unblank
arch: um: kmsg_dump: Use console_is_usable
drivers: serial: kgdboc: Drop checks for CON_ENABLED and CON_BOOT
lib/vsprintf: Unify FORMAT_STATE_NUM handlers
printk: Avoid irq_work for printk_deferred() on suspend
printk: Avoid scheduling irq_work on suspend
printk: Allow printk_trigger_flush() to flush all types
tracing: Switch to use %ptSp
scsi: snic: Switch to use %ptSp
scsi: fnic: Switch to use %ptSp
s390/dasd: Switch to use %ptSp
ptp: ocp: Switch to use %ptSp
pps: Switch to use %ptSp
PCI: epf-test: Switch to use %ptSp
net: dsa: sja1105: Switch to use %ptSp
mmc: mmc_test: Switch to use %ptSp
media: av7110: Switch to use %ptSp
ipmi: Switch to use %ptSp
igb: Switch to use %ptSp
e1000e: Switch to use %ptSp
...

These callbacks are necessary to synchronize ->write_thread callback
against other operations using the same device.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20251208-nbcon-device-cb-fix-v2-1-36be8d195123@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>

Pull workqueue updates from Tejun Heo:

- Rework the rescuer to process work items one-by-one instead of
slurping all pending work items in a single pass.

As there is only one rescuer per workqueue, a single long-blocking
work item could cause high latency for all tasks queued behind it,
even after memory pressure is relieved and regular kworkers become
available to service them.

- Add CONFIG_BOOTPARAM_WQ_STALL_PANIC build-time option and
workqueue.panic_on_stall_time parameter for time-based stall panic,
giving systems more control over workqueue stall handling.

- Replace BUG_ON() with panic() in the stall panic path for clearer
intent and more informative output.

* tag 'wq-for-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: replace BUG_ON with panic in panic_on_wq_watchdog
workqueue: add time-based panic for stalls
workqueue: add CONFIG_BOOTPARAM_WQ_STALL_PANIC option
workqueue: Process extra works in rescuer on memory pressure
workqueue: Process rescuer work items one-by-one using a cursor
workqueue: Make send_mayday() take a PWQ argument directly

A warning was detect:

WARNING: kernel/cgroup/cpuset.c:825 at rebuild_sched_domains_locked
Modules linked in:
CPU: 12 UID: 0 PID: 681 Comm: rmdir 6.19.0-rc6-next-20260121+
RIP: 0010:rebuild_sched_domains_locked+0x309/0x4b0
RSP: 0018:ffffc900019bbd28 EFLAGS: 00000202
RAX: ffff888104413508 RBX: 0000000000000008 RCX: ffff888104413510
RDX: ffff888109b5f400 RSI: 000000000000ffcf RDI: 0000000000000001
RBP: 0000000000000002 R08: ffff888104413508 R09: 0000000000000002
R10: ffff888104413508 R11: 0000000000000001 R12: ffff888104413500
R13: 0000000000000002 R14: ffffc900019bbd78 R15: 0000000000000000
FS: 00007fe274b8d740(0000) GS:ffff8881b6b3c000(0000) knlGS:
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe274c98b50 CR3: 00000001047a9000 CR4: 00000000000006f0
Call Trace:
<TASK>
update_prstate+0x1c7/0x580
cpuset_css_killed+0x2f/0x50
kill_css+0x32/0x180
cgroup_destroy_locked+0xa7/0x200
cgroup_rmdir+0x28/0x100
kernfs_iop_rmdir+0x4c/0x80
vfs_rmdir+0x12c/0x280
filename_rmdir+0x19e/0x200
__x64_sys_rmdir+0x23/0x40
do_syscall_64+0x6b/0x390

It can be reproduced by steps:

# cd /sys/fs/cgroup/
# mkdir A1
# mkdir B1
# mkdir C1
# echo 1-3 > A1/cpuset.cpus
# echo root > A1/cpuset.cpus.partition
# echo 3-5 > B1/cpuset.cpus
# echo root > B1/cpuset.cpus.partition
# echo 6 > C1/cpuset.cpus
# echo root > C1/cpuset.cpus.partition
# rmdir A1/
# rmdir C1/

Both A1 and B1 were initially configured with CPU 3, which was exclusively
assigned to A1's partition. When A1 was removed, CPU 3 was returned to the
root pool. However, B1 incorrectly regained access to CPU 3 when
update_cpumasks_hier was triggered during C1's removal, which also updated
sibling configurations.

The update_sibling_cpumasks function was called to synchronize siblings'
effective CPUs due to changes in their parent's effective CPUs. However,
parent effective CPU changes should not affect partition-effective CPUs.

To fix this issue, update_cpumasks_hier should only be invoked when the
sibling is not a valid partition in the update_sibling_cpumasks.

Fixes: 2a3602030d80 ("cgroup/cpuset: Don't invalidate sibling partitions on cpuset.cpus conflict")
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Fix a pointer arithmetic error in scx_sdt during freeing that
causes the allocator to use the wrong memory address for the
allocation's data header.

Fixes: 36929ebd17ae ("tools/sched_ext: add arena based scheduler")
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Add support for pbzip2, xz and plzip which can compress in parallel.
This speeds up the ramdisk compression.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://patch.msgid.link/20260106162738.2605574-6-sjg@chromium.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

When a cache has high s->align value and s->object_size is not aligned
to it, each object ends up with some unused space because of alignment.
If this wasted space is big enough, we can use it to store the
slabobj_ext metadata instead of wasting it.

On my system, this happens with caches like kmem_cache, mm_struct, pid,
task_struct, sighand_cache, xfs_inode, and others.

To place the slabobj_ext metadata within each object, the existing
slab_obj_ext() logic can still be used by setting:

- slab->obj_exts = slab_address(slab) + (slabobj_ext offset)
- stride = s->size

slab_obj_ext() doesn't need know where the metadata is stored,
so this method works without adding extra overhead to slab_obj_ext().

A good example benefiting from this optimization is xfs_inode
(object_size: 992, align: 64). To measure memory savings, 2 millions of
files were created on XFS.

[ MEMCG=y, MEM_ALLOC_PROFILING=n ]

Before patch (creating ~2.64M directories on xfs):
Slab: 5175976 kB
SReclaimable: 3837524 kB
SUnreclaim: 1338452 kB

After patch (creating ~2.64M directories on xfs):
Slab: 5152912 kB
SReclaimable: 3838568 kB
SUnreclaim: 1314344 kB (-23.54 MiB)

Enjoy the memory savings!

Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260113061845.159790-10-harry.yoo@oracle.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

The cpu slabs and their deactivations were removed, so remove the unused
stat items. Weirdly enough the values were also used to control
__add_partial() adding to head or tail of the list, so replace that with
a new enum add_mode, which is cleaner.

Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Hao Li <hao.li@linux.dev>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Pull ftrace fix from Steven Rostedt:

- Fix allocation accounting on boot up

The ftrace records for each function that ftrace can attach to is
done in a group of pages. At boot up, the number of pages are
calculated and allocated. After that, the pages are filled with data.
It may allocate more than needed due to some functions not being
recorded (because they are unused weak functions), this too is
recorded.

After the data is filled in, a check is made to make sure the right
number of pages were allocated. But this was off due to the
assumption that the same number of entries fit per every page.
Because the size of an entry does not evenly divide into PAGE_SIZE,
there is a rounding error when a large number of pages is allocated
to hold the events. This causes the check to fail and triggers a
warning.

Fix the accounting by finding out how many pages are actually
allocated from the functions that allocate them and use that to see
if all the pages allocated were used and the ones not used are
properly freed.

* tag 'ftrace-v6.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ftrace: Do not over-allocate ftrace memory

The last rtg should be able to grow when the size of the last is less
than (and not equal to) sb_rgextents. xfs_growfs with realtime groups
fails without this patch. The reason is that, xfs_growfs_rtg() tries
to grow the last rt group even when the last rt group is at its
maximal size i.e, sb_rgextents. It fails with the following messages:

XFS (loop0): Internal error block >= mp->m_rsumblocks at line 253 of file fs/xfs/libxfs/xfs_rtbitmap.c. Caller xfs_rtsummary_read_buf+0x20/0x80
XFS (loop0): Corruption detected. Unmount and run xfs_repair
XFS (loop0): Internal error xfs_trans_cancel at line 976 of file fs/xfs/xfs_trans.c. Caller xfs_growfs_rt_bmblock+0x402/0x450
XFS (loop0): Corruption of in-memory data (0x8) detected at xfs_trans_cancel+0x10a/0x1f0 (fs/xfs/xfs_trans.c:977). Shutting down filesystem.
XFS (loop0): Please unmount the filesystem and rectify the problem(s)

Signed-off-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Pull lkmm documentation update from Paul McKenney:

- Sort the memory-barriers.txt file's wait_event* and wait_on_bit* list
alphabetically

* tag 'lkmm.2025.12.01a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
memory-barriers.txt: Sort wait_event* and wait_on_bit* list alphabetically

Shinichiro reported a KASAN UAF, which is actually an out of bounds access
in the MMCID management code.

CPU0 CPU1
T1 runs in userspace
T0: fork(T4) -> Switch to per CPU CID mode
fixup() set MM_CID_TRANSIT on T1/CPU1
T4 exit()
T3 exit()
T2 exit()
T1 exit() switch to per task mode
---> Out of bounds access.

As T1 has not scheduled after T0 set the TRANSIT bit, it exits with the
TRANSIT bit set. sched_mm_cid_remove_user() clears the TRANSIT bit in
the task and drops the CID, but it does not touch the per CPU storage.
That's functionally correct because a CID is only owned by the CPU when
the ONCPU bit is set, which is mutually exclusive with the TRANSIT flag.

Now sched_mm_cid_exit() assumes that the CID is CPU owned because the
prior mode was per CPU. It invokes mm_drop_cid_on_cpu() which clears the
not set ONCPU bit and then invokes clear_bit() with an insanely large
bit number because TRANSIT is set (bit 29).

Prevent that by actually validating that the CID is CPU owned in
mm_drop_cid_on_cpu().

Fixes: 007d84287c74 ("sched/mmcid: Drop per CPU CID immediately when switching to per task mode")
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/aYsZrixn9b6s_2zL@shinmob
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Replace BUG_ON() with panic() in panic_on_wq_watchdog(). This is not
a bug condition but a deliberate forced panic requested by the user
via module parameters to crash the system for debugging purposes.

Using panic() instead of BUG_ON() makes this intent clearer and provides
more informative output about which threshold was exceeded and the actual
values, making it easier to diagnose the stall condition from crash dumps.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

The current cgroup subsystem limit of 16 is insufficient, as the number of
existing subsystems has already reached this limit. When adding a new
subsystem that is not yet in the mainline kernel, building with
`make allmodconfig` requires first bypassing the
`BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16)` restriction to allow compilation
to succeed. However, the kernel still fails to boot afterward.

This patch increases the maximum number of supported cgroup subsystems from
16 to 32, providing enough room for future subsystem additions.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: Waiman Long <longman@redhat.com>
Tested-by: JP Kobryn <inwardvessel@gmail.com>
Acked-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Add scx_bpf_error() calls when scx_bpf_create_dsq() fails in the remaining
schedulers to improve debuggability:

- scx_simple.bpf.c: simple_init()
- scx_sdt.bpf.c: sdt_init()
- scx_cpu0.bpf.c: cpu0_init()
- scx_flatcg.bpf.c: fcg_init()

This follows the same pattern established in commit 2f8d489897ae
("sched_ext: Add error logging for dsq creation failures") for other
schedulers and ensures consistent error reporting across all schedulers.

Signed-off-by: zhidao su <suzhidao@xiaomi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

In some cases it is useful to be able to pass additional flags to the
make_fit.py script. For example, since ramdisks are typically large,
passing -E to use external data can be helpful.

Add a new FIT_EXTRA_ARGS variable for this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20260106162738.2605574-5-sjg@chromium.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

To access SLUB's internal implementation details beyond cache flags in
ksize(), move __ksize(), ksize(), and slab_ksize() to mm/slub.c.

[vbabka@suse.cz: also make __ksize() static and move its kerneldoc to
ksize() ]

Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260113061845.159790-9-harry.yoo@oracle.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Currently slabs are only frozen after consistency checks failed. This
can happen only in caches with debugging enabled, and those use
free_to_partial_list() for freeing. The non-debug operation of
__slab_free() can thus stop considering the frozen field, and we can
remove the FREE_FROZEN stat.

Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Hao Li <hao.li@linux.dev>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Pull NFS client fixes from Trond Myklebust:

- Fix another deadlock involving nfs_release_folio()

- localio:
- Stop I/O upon hitting a fatal error
- Deal with page offsets that are > PAGE_SIZE

- Fix size read races in truncate, fallocate and copy offload

- Several bugfixes for the NFSv4.x directory delegation client code

- pNFS:
- Fix a deadlock when returning delegations during open
- Fix memory leaks in various error paths

* tag 'nfs-for-6.19-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFS: Fix size read races in truncate, fallocate and copy offload
NFS: Don't immediately return directory delegations when disabled
NFS/localio: Deal with page bases that are > PAGE_SIZE
NFS/localio: Stop further I/O upon hitting an error
NFSv4.x: Directory delegations don't require any state recovery
NFSv4: Don't free slots prematurely if requesting a directory delegation
NFSv4: Fix nfs_clear_verifier_delegated() for delegated directories
NFS: Fix directory delegation verifier checks
pnfs/blocklayout: Fix memory leak in bl_parse_scsi()
pnfs/flexfiles: Fix memory leak in nfs4_ff_alloc_deviceid_node()
NFS: Fix a deadlock involving nfs_release_folio()
pNFS: Fix a deadlock when returning a delegation during open()

The pg_remaining calculation in ftrace_process_locs() assumes that
ENTRIES_PER_PAGE multiplied by 2^order equals the actual capacity of the
allocated page group. However, ENTRIES_PER_PAGE is PAGE_SIZE / ENTRY_SIZE
(integer division). When PAGE_SIZE is not a multiple of ENTRY_SIZE (e.g.
4096 / 24 = 170 with remainder 16), high-order allocations (like 256 pages)
have significantly more capacity than 256 * 170. This leads to pg_remaining
being underestimated, which in turn makes skip (derived from skipped -
pg_remaining) larger than expected, causing the WARN(skip != remaining)
to trigger.

Extra allocated pages for ftrace: 2 with 654 skipped
WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:7295 ftrace_process_locs+0x5bf/0x5e0

A similar problem in ftrace_allocate_records() can result in allocating
too many pages. This can trigger the second warning in
ftrace_process_locs().

Extra allocated pages for ftrace
WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:7276 ftrace_process_locs+0x548/0x580

Use the actual capacity of a page group to determine the number of pages
to allocate. Have ftrace_allocate_pages() return the number of allocated
pages to avoid having to calculate it. Use the actual page group capacity
when validating the number of unused pages due to skipped entries.
Drop the definition of ENTRIES_PER_PAGE since it is no longer used.

Cc: stable@vger.kernel.org
Fixes: 4a3efc6baff93 ("ftrace: Update the mcount_loc check of skipped entries")
Link: https://patch.msgid.link/20260113152243.3557219-1-linux@roeck-us.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Move each condition into a separate assert so that we can see which
on triggered.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Pull RCU updates from Frederic Weisbecker:
"SRCU:

- Properly handle SRCU readers within IRQ disabled sections in tiny
SRCU

- Preparation to reimplement RCU Tasks Trace on top of SRCU fast:

- Introduce API to expedite a grace period and test it through
rcutorture

- Split srcu-fast in two flavours: SRCU-fast and SRCU-fast-updown.

Both are still targeted toward faster readers (without full
barriers on LOCK and UNLOCK) at the expense of heavier write
side (using full RCU grace period ordering instead of simply
full ordering) as compared to "traditional" non-fast SRCU. But
those srcu-fast flavours are going to be optimized in two
different ways:

- SRCU-fast will become the reimplementation basis for
RCU-TASK-TRACE for consolidation. Since RCU-TASK-TRACE must
be NMI safe, SRCU-fast must be as well.

- SRCU-fast-updown will be needed for uretprobes code in order
to get rid of the read-side memory barriers while still
allowing entering the reader at task level while exiting it
in a timer handler. It is considered semaphore-like in that
it can have different owners between LOCK and UNLOCK.
However it is not NMI-safe.

The actual optimizations are work in progress for the next
cycle. Only the new interfaces are added for now, along with
related torture and scalability test code.

- Create/document/debug/torture new proper initializers for RCU fast:
DEFINE_SRCU_FAST() and init_srcu_struct_fast()

This allows for using right away the proper ordering on the write
side (either full ordering or full RCU grace period ordering)
without waiting for the read side to tell which to use.

This also optimizes the read side altogether with moving flavour
debug checks under debug config and with removing a costly RmW
operation on their first call.

- Make some diagnostic functions tracing safe

Refscale:

- Add performance testing for common context synchronizations
(Preemption, IRQ, Softirq) and per-cpu increments. Those are
relevant comparisons against SRCU-fast read side APIs, especially
as they are planned to synchronize further tracing fast-path code

Miscellanous:

- In order to prepare the layout for nohz_full work deferral to user
exit, the context tracking state must shrink the counter of
transitions to/from RCU not watching. The only possible hazard is
to trigger wrap-around more easily, delaying a bit grace periods
when that happens. This should be a rare event though. Yet add
debugging and torture code to test that assumption

- Fix memory leak on locktorture module

- Annotate accesses in rculist_nulls.h to prevent from KCSAN
warnings. On recent discussions, we also concluded that all those
WRITE_ONCE() and READ_ONCE() on list APIs deserve appropriate
comments. Something to be expected for the next cycle

- Provide a script to apply several configs to several commits with
torture

- Allow torture to reuse a build directory in order to save needless
rebuild time

- Various cleanups"

* tag 'rcu.release.v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (29 commits)
refscale: Add SRCU-fast-updown readers
refscale: Exercise DEFINE_STATIC_SRCU_FAST() and init_srcu_struct_fast()
rcutorture: Make srcu{,d}_torture_init() announce the SRCU type
srcu: Create an SRCU-fast-updown API
refscale: Do not disable interrupts for tests involving local_bh_enable()
refscale: Add non-atomic per-CPU increment readers
refscale: Add this_cpu_inc() readers
refscale: Add preempt_disable() readers
refscale: Add local_bh_disable() readers
refscale: Add local_irq_disable() and local_irq_save() readers
torture: Permit negative kvm.sh --kconfig numberic arguments
srcu: Add SRCU_READ_FLAVOR_FAST_UPDOWN CPP macro
rcu: Mark diagnostic functions as notrace
rcutorture: Make TREE04 use CONFIG_RCU_DYNTICKS_TORTURE
rcutorture: Remove redundant rcutorture_one_extend() from rcu_torture_one_read()
rcutorture: Permit kvm-again.sh to re-use the build directory
torture: Add kvm-series.sh to test commit/scenario combination
rcu: use WRITE_ONCE() for ->next and ->pprev of hlist_nulls
locktorture: Fix memory leak in param_set_cpumask()
doc: Update for SRCU-fast definitions and initialization
...

Commit 88172700423c ("docs/memory-barriers.txt: Add wait_event_cmd()
and wait_event_exclusive_cmd()") added two APIs without taking care
of the list order. Sort the list for readability.

While there, make it clear that this is incomplete by saying
"for example".

Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

There may be console drivers that have not yet figured out a way
to implement safe atomic printing (->write_atomic() callback).
These drivers could choose to only implement threaded printing
(->write_thread() callback), but then it is guaranteed that _no_
output will be printed during panic. Not even attempted.

As a result, developers may be tempted to implement unsafe
->write_atomic() callbacks and/or implement some sort of custom
deferred printing trickery to try to make it work. This goes
against the principle intention of the nbcon API as well as
endangers other nbcon drivers that are doing things correctly
(safely).

As a compromise, allow nbcon drivers to implement unsafe
->write_atomic() callbacks by providing a new console flag
CON_NBCON_ATOMIC_UNSAFE. When specified, the ->write_atomic()
callback for that console will _only_ be called during the
final "hope and pray" flush attempt at the end of a panic:
nbcon_atomic_flush_unsafe().

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/lkml/b2qps3uywhmjaym4mht2wpxul4yqtuuayeoq4iv4k3zf5wdgh3@tocu6c7mj4lt
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/all/swdpckuwwlv3uiessmtnf2jwlx3jusw6u7fpk5iggqo4t2vdws@7rpjso4gr7qp/ [1]
Link: https://lore.kernel.org/all/20251103-fix_netpoll_aa-v4-1-4cfecdf6da7c@debian.org/ [2]
Link: https://patch.msgid.link/20251027161212.334219-2-john.ogness@linutronix.de
[pmladek@suse.com: Fix build with rework/nbcon-in-kdb branch.]
Signed-off-by: Petr Mladek <pmladek@suse.com>

Pull drm updates from Dave Airlie:
"Highlights:
- amdgpu support for lots of new IP blocks which means newer GPUs
- xe has a lot of SR-IOV and SVM improvements
- lots of intel display refactoring across i915/xe
- msm has more support for gen8 platforms
- Given up on kgdb/kms integration, it's too hard on modern hw

core:
- drop kgdb support
- replace system workqueue with percpu
- account for property blobs in memcg
- MAINTAINERS updates for xe + buddy

rust:
- Fix documentation for Registration constructors
- Use pin_init::zeroed() for fops initialization
- Annotate DRM helpers with __rust_helper
- Improve safety documentation for gem::Object::new()
- Update AlwaysRefCounted imports
- mm: Prevent integer overflow in page_align()

atomic:
- add drm_device pointer to drm_private_obj
- introduce gamma/degamma LUT size check

buddy:
- fix free_trees memory leak
- prevent BUG_ON

bridge:
- introduce drm_bridge_unplug/enter/exit
- add connector argument to .hpd_notify
- lots of recounting conversions
- convert rockchip inno hdmi to bridge
- lontium-lt9611uxc: switch to HDMI audio helpers
- dw-hdmi-qp: add support for HPD-less setups
- Algoltek AG6311 support

panels:
- edp: CSW MNE007QB3-1, AUO B140HAN06.4, AUO B140QAX01.H
- st75751: add SPI support
- Sitronix ST7920, Samsung LTL106HL02
- LG LH546WF1-ED01, HannStar HSD156J
- BOE NV130WUM-T08
- Innolux G150XGE-L05
- Anbernic RG-DS

dma-buf:
- improve sg_table debugging
- add tracepoints
- call clear_page instead of memset
- start to introduce cgroup memory accounting in heaps
- remove sysfs stats

dma-fence:
- add new helpers

dp:
- mst: avoid oob access with vcpi=0

hdmi:
- limit infoframes exposure to userspace

gem:
- reduce page table overhead with THP
- fix leak in drm_gem_get_unmapped_area

gpuvm:
- API sanitation for rust bindings

sched:
- introduce new helpers

panic:
- report invalid panic modes
- add kunit tests

i915/xe display:
- Expose sharpness only if num_scalers is >= 2
- Add initial Xe3P_LPD for NVL
- BMG FBC support
- Add MTL+ platforms to support dpll framework
_ fix DIMM_S DRM decoding on ICL
- Return to using AUX interrupts
- PSR/Panel replay refactoring
- use consolidation HDMI tables
- Xe3_LPD CD2X dividier changes

xe:
- vfio: add vfio_pci for intel GPU
- multi queue support
- dynamic pagemaps and multi-device SVM
- expose temp attribs in hwmon
- NO_COMPRESSION bo flag
- expose MERT OA unit
- sysfs survivability refactor
- SRIOV PF: add MERT support
- enable SR-IOV VF migration
- Enable I2C/NVM on Crescent Island
- Xe3p page reclaimation support
- introduce SRIOV scheduler groups
- add SoC remappt support in system controller
- insert compiler barriers in GuC code
- define NVL GuC firmware
- handle GT resume failure
- fix drm scheduler layering violations
- enable GSC loading and PXP for PTL
- disable GuC Power DCC strategy on PTL
- unregister drm device on probe error

i915:
- move to kernel standard fault injection
- bump recommended GuC version for DG2 and MTL

amdgpu:
- SMUIO 15.x, PSP 15.x support
- IH 6.1.1/7.1 support
- MMHUB 3.4/4.2 support
- GC 11.5.4/12.1 support
- SDMA 6.1.4/7.1/7.11.4 support
- JPEG 5.3 support
- UserQ updates
- GC 9 gfx queue reset support
- TTM memory ops parallelization
- convert legacy logging to new helpers
- DC analog fixes

amdkfd:
- GC 11.5.4/12.1 suppport
- SDMA 6.1.4/7.1 support
- per context support
- increase kfd process hash table
- Reserved SDMA rework

radeon:
- convert legacy logging to new helpers
- use devm for i2c adapters

msm:
- GPU
- Document a612/RGMU dt bindings
- UBWC 6.0 support (for A840 / Kaanapali)
- a225 support
- DPU:
- Switch to use virtual planes by default
- Fix DSI CMD panels on DPU 3.x
- Rewrite format handling to remove intermediate representation
- Fix watchdog on DPU 8.x+
- Fix TE / Vsync source setting on DPU 8.x+
- Add 3D_Mux on SC7280
- Kaanapali platform support
- Fix UBWC register programming
- Make RM reserve DSPP-enabled mixers for CRTCs with LMs
- Gamma correction support
- DP:
- Enable support for eDP 1.4+ link rate tables
- Fix MDSS1 DP indices on SA8775P, making them to work
- Fix msm_dp_ctrl_config_msa() to work with LLVM 20
- DSI:
- Document QCS8300 as compatible with SA8775P
- Kaanapali platform support
- DSI PHY:
- switch to divider_determine_rate()
- MDP5:
- Drop support for MSM8998, SDM660 and SDM630 (switch over to DPU)
- MDSS:
- Kaanapali platform support
- Fixed UBWC register programming

nova-core:
- Prepare for Turing support. This includes parsing and handling
Turing-specific firmware headers and sections as well as a Turing
Falcon HAL implementation
- Get rid of the Result<impl PinInit<T, E>> anti-pattern
- Relocate initializer-specific code into the appropriate initializer
- Use CStr::from_bytes_until_nul() to remove custom helpers
- Improve handling of unexpected firmware values
- Clean up redundant debug prints
- Replace c_str!() with native Rust C-string literals
- Update nova-core task list

nova:
- Align GEM object size to system page size

tyr:
- Use generated uAPI bindings for GpuInfo
- Replace manual sleeps with read_poll_timeout()
- Replace c_str!() with native Rust C-string literals
- Suppress warnings for unread fields
- Fix incorrect register name in print statement

nouveau:
- fix big page table support races in PTE management
- improve reclocking on tegra 186+

amdxdna:
- fix suspend race conditions
- improve handling of zero tail pointers
- fix cu_idx overwritten during command setup
- enable hardware context priority
- remove NPU2 support
- update message buffer allocation requirements
- update firmware version check

ast:
- support imported cursor buffers
- big endian fixes

etnaviv:
- add PPU flop reset support

imagination:
- add AM62P support
- introduce hw version checks

ivpu:
- implement warm boot flow

panfrost:
- add bo sync ioctl
- add GPU_PM_RT support for RZ/G3E SoC

panthor:
- add bo sync ioctl
- enable timestamp propagation
- scheduler robustness improvements
- VM termination fixes
- huge page support

rockchip:
- RK3368 HDMI Support
- get rid of atomic_check fixups
- RK3506 support
- RK3576/RK3588 improved HPD handling

rz-du:
- RZ/V2H(P) MIPI-DSI Support

v3d:
- fix DMA segment size
- convert to new logging helpers

mediatek:
- move DP training to hotplug thread
- convert logging to new helpers
- add support for HS speed DSI
- Genio 510/700/1200-EVK, Radxa NIO-12L HDMI support

atmel-hlcdc:
- switch to drmm resource
- support nomodeset
- use newer helpers

hisilicon:
- fix various DP bugs

renesas:
- fix kernel panic on reboot

exynos:
- fix vidi_connection_ioctl using wrong device
- fix vidi_connection deref user ptr
- fix concurrency regression with vidi_context

vkms:
- add configfs support for display configuration

* tag 'drm-next-2026-02-11' of https://gitlab.freedesktop.org/drm/kernel: (1610 commits)
drm/xe/pm: Disable D3Cold for BMG only on specific platforms
drm/xe: Fix kerneldoc for xe_tlb_inval_job_alloc_dep
drm/xe: Fix kerneldoc for xe_gt_tlb_inval_init_early
drm/xe: Fix kerneldoc for xe_migrate_exec_queue
drm/xe/query: Fix topology query pointer advance
drm/xe/guc: Fix kernel-doc warning in GuC scheduler ABI header
drm/xe/guc: Fix CFI violation in debugfs access.
accel/amdxdna: Move RPM resume into job run function
accel/amdxdna: Fix incorrect DPM level after suspend/resume
nouveau/vmm: start tracking if the LPT PTE is valid. (v6)
nouveau/vmm: increase size of vmm pte tracker struct to u32 (v2)
nouveau/vmm: rewrite pte tracker using a struct and bitfields.
accel/amdxdna: Fix incorrect error code returned for failed chain command
accel/amdxdna: Remove hardware context status
drm/bridge: imx8qxp-pixel-combiner: Fix bailout for imx8qxp_pc_bridge_probe()
drm/panel: ilitek-ili9882t: Remove duplicate initializers in tianma_il79900a_dsc
drm/i915/display: fix the pixel normalization handling for xe3p_lpd
drm/exynos: vidi: use ctx->lock to protect struct vidi_context member variables related to memory alloc/free
drm/exynos: vidi: fix to avoid directly dereferencing user pointer
drm/exynos: vidi: use priv->vidi_dev for ctx lookup in vidi_connection_ioctl()
...

Add a new module parameter 'panic_on_stall_time' that triggers a panic
when a workqueue stall persists for longer than the specified duration
in seconds.

Unlike 'panic_on_stall' which counts accumulated stall events, this
parameter triggers based on the duration of a single continuous stall.
This is useful for catching truly stuck workqueues rather than
accumulating transient stalls.

Usage:
workqueue.panic_on_stall_time=120

This would panic if any workqueue pool has been stalled for 120 seconds
or more.

The stall duration is measured from the workqueue last progress
(poll_ts) which accounts for legitimate system stalls.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

cpu.rt.max was a proposed interface that never landed in mainline. Remove the
reference from cgroup-v2 documentation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Orestis Floros <orestisflo@gmail.com>

Add a scheduler that uses BPF arenas to manage task context data.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Since build_fit() is getting quite long, move the dtb processing into a
separate function.

Change the double quotes in the write() call to single, to match the
rest of the script.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://patch.msgid.link/20260106162738.2605574-4-sjg@chromium.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

The leftover space in a slab is always smaller than s->size, and
kmem caches for large objects that are not power-of-two sizes tend to have
a greater amount of leftover space per slab. In some cases, the leftover
space is larger than the size of the slabobj_ext array for the slab.

An excellent example of such a cache is ext4_inode_cache. On my system,
the object size is 1136, with a preferred order of 3, 28 objects per slab,
and 960 bytes of leftover space per slab.

Since the size of the slabobj_ext array is only 224 bytes (w/o mem
profiling) or 448 bytes (w/ mem profiling) per slab, the entire array
fits within the leftover space.

Allocate the slabobj_exts array from this unused space instead of using
kcalloc() when it is large enough. The array is allocated from unused
space only when creating new slabs, and it doesn't try to utilize unused
space if alloc_slab_obj_exts() is called after slab creation because
implementing lazy allocation involves more expensive synchronization.

The implementation and evaluation of lazy allocation from unused space
is left as future-work. As pointed by Vlastimil Babka [1], it could be
beneficial when a slab cache without SLAB_ACCOUNT can be created, and
some of the allocations from the cache use __GFP_ACCOUNT. For example,
xarray does that.

To avoid unnecessary overhead when MEMCG (with SLAB_ACCOUNT) and
MEM_ALLOC_PROFILING are not used for the cache, allocate the slabobj_ext
array only when either of them is enabled on slab allocation.

[ MEMCG=y, MEM_ALLOC_PROFILING=n ]

Before patch (creating ~2.64M directories on ext4):
Slab: 4747880 kB
SReclaimable: 4169652 kB
SUnreclaim: 578228 kB

After patch (creating ~2.64M directories on ext4):
Slab: 4724020 kB
SReclaimable: 4169188 kB
SUnreclaim: 554832 kB (-22.84 MiB)

Enjoy the memory savings!

Link: https://lore.kernel.org/linux-mm/48029aab-20ea-4d90-bfd1-255592b2018e@suse.cz [1]
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260113061845.159790-8-harry.yoo@oracle.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

The changes related to sheaves made the description of locking and other
details outdated. Update it to reflect current state.

Also add a new copyright line due to major changes.

Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Hao Li <hao.li@linux.dev>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Pull EFI fixes from Ard Biesheuvel:

- Wipe the INITRD config table upon consumption so it doesn't confuse
kexec

- Let APEI/GHES maintainers take responsibility for CPER processing
logic

- Fix wrong return value in CPER string helper routine

* tag 'efi-fixes-for-v6.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
efi/cper: Fix cper_bits_to_str buffer handling and return value
MAINTAINERS: add cper to APEI files
efi: Wipe INITRD config table from memory after consumption

If the pre-operation file size is read before locking the inode and
quiescing O_DIRECT writes, then nfs_truncate_last_folio() might end up
overwriting valid file data.

Fixes: b1817b18ff20 ("NFS: Protect against 'eof page pollution'")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>