Pull scheduler fixes from Borislav Petkov:
- Fix a stall on the CPU offline path due to mis-counting a deadline
server task twice as part of the runqueue's running tasks count
- Fix a realtime tasks starvation case where failure to enqueue a timer
whose expiration time is already in the past would cause repeated
attempts to re-enqueue a deadline server task which leads to starving
the former, realtime one
- Prevent a delayed deadline server task stop from breaking the
per-runqueue bandwidth tracking
- Have a function checking whether the deadline server task has
stopped, return the correct value
* tag 'sched_urgent_for_v6.17_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Don't count nr_running for dl_server proxy tasks
sched/deadline: Fix RT task potential starvation when expiry time passed
sched/deadline: Always stop dl-server before changing parameters
sched/deadline: Fix dl_server_stopped()
To avoid a memory leak via mm_alloc() + mmdrop() the futex cleanup code
has been moved to __mmdrop(). This resulted in a warnings if the futex
hash table has been allocated via vmalloc() the mmdrop() was invoked
from atomic context.
The free path must stay in __mmput() to ensure it is invoked from
preemptible context.
In order to avoid the memory leak, delay the allocation of
mm_struct::mm->futex_ref to futex_hash_allocate(). This works because
neither the per-CPU counter nor the private hash has been allocated and
therefore
- futex_private_hash() callers (such as exit_pi_state_list()) don't
acquire reference if there is no private hash yet. There is also no
reference put.
- Regular callers (futex_hash()) fallback to global hash. No reference
counting here.
The futex_ref member can be allocated in futex_hash_allocate() before
the private hash itself is allocated. This happens either while the
first thread is created or on request. In both cases the process has
just a single thread so there can be either futex operation in progress
or the request to create a private hash.
Move futex_hash_free() back to __mmput();
Move the allocation of mm_struct::futex_ref to futex_hash_allocate().
[ bp: Fold a follow-up fix to prevent a use-after-free:
https://lore.kernel.org/r/20250830213806.sEKuuGSm@linutronix.de ]
Fixes: e703b7e247 ("futex: Move futex cleanup to __mmdrop()")
Closes: https://lore.kernel.org/all/20250821102721.6deae493@kernel.org/
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lkml.kernel.org/r/20250822141238.PfnkTjFb@linutronix.de
Pull dma-mapping fixes from Marek Szyprowski:
- another small fix for arm64 systems with memory encryption (Shanker
Donthineni)
- fix for arm32 systems with non-standard CMA configuration (Oreoluwa
Babatunde)
* tag 'dma-mapping-6.17-2025-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
dma/pool: Ensure DMA_DIRECT_REMAP allocations are decrypted
of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()
On CPU offline the kernel stalled with below call trace:
INFO: task kworker/0:1:11 blocked for more than 120 seconds.
cpuhp hold the cpu hotplug lock endless and stalled vmstat_shepherd.
This is because we count nr_running twice on cpuhp enqueuing and failed
the wait condition of cpuhp:
enqueue_task_fair() // pick cpuhp from idle, rq->nr_running = 0
dl_server_start()
[...]
add_nr_running() // rq->nr_running = 1
add_nr_running() // rq->nr_running = 2
[switch to cpuhp, waiting on balance_hotplug_wait()]
rcuwait_wait_event(rq->nr_running == 1 && ...) // failed, rq->nr_running=2
schedule() // wait again
It doesn't make sense to count the dl_server towards runnable tasks,
since it runs other tasks.
Fixes: 63ba8422f8 ("sched/deadline: Introduce deadline servers")
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250627035420.37712-1-yangyicong@huawei.com
[Symptom]
The fair server mechanism, which is intended to prevent fair starvation
when higher-priority tasks monopolize the CPU.
Specifically, RT tasks on the runqueue may not be scheduled as expected.
[Analysis]
The log "sched: DL replenish lagged too much" triggered.
By memory dump of dl_server:
curr = 0xFFFFFF80D6A0AC00 (
dl_server = 0xFFFFFF83CD5B1470(
dl_runtime = 0x02FAF080,
dl_deadline = 0x3B9ACA00,
dl_period = 0x3B9ACA00,
dl_bw = 0xCCCC,
dl_density = 0xCCCC,
runtime = 0x02FAF080,
deadline = 0x0000082031EB0E80,
flags = 0x0,
dl_throttled = 0x0,
dl_yielded = 0x0,
dl_non_contending = 0x0,
dl_overrun = 0x0,
dl_server = 0x1,
dl_server_active = 0x1,
dl_defer = 0x1,
dl_defer_armed = 0x0,
dl_defer_running = 0x1,
dl_timer = (
node = (
expires = 0x000008199756E700),
_softexpires = 0x000008199756E700,
function = 0xFFFFFFDB9AF44D30 = dl_task_timer,
base = 0xFFFFFF83CD5A12C0,
state = 0x0,
is_rel = 0x0,
is_soft = 0x0,
clock_update_flags = 0x4,
clock = 0x000008204A496900,
- The timer expiration time (rq->curr->dl_server->dl_timer->expires)
is already in the past, indicating the timer has expired.
- The timer state (rq->curr->dl_server->dl_timer->state) is 0.
[Suspected Root Cause]
The relevant code flow in the throttle path of
update_curr_dl_se() as follows:
dequeue_dl_entity(dl_se, 0); // the DL entity is dequeued
if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(dl_se))) {
if (dl_server(dl_se)) // timer registration fails
enqueue_dl_entity(dl_se, ENQUEUE_REPLENISH);//enqueue immediately
...
}
The failure of `start_dl_timer` is caused by attempting to register a
timer with an expiration time that is already in the past. When this
situation persists, the code repeatedly re-enqueues the DL entity
without properly replenishing or restarting the timer, resulting in RT
task may not be scheduled as expected.
[Proposed Solution]:
Instead of immediately re-enqueuing the DL entity on timer registration
failure, this change ensures the DL entity is properly replenished and
the timer is restarted, preventing RT potential starvation.
Fixes: 63ba8422f8 ("sched/deadline: Introduce deadline servers")
Signed-off-by: kuyo chang <kuyo.chang@mediatek.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Closes: https://lore.kernel.org/CAMuHMdXn4z1pioTtBGMfQM0jsLviqS2jwysaWXpoLxWYoGa82w@mail.gmail.com
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Tested-by: Diederik de Haas <didi.debian@cknow.org>
Link: https://lkml.kernel.org/r/20250615131129.954975-1-kuyo.chang@mediatek.com
Commit cccb45d7c4 ("sched/deadline: Less agressive dl_server
handling") reduced dl-server overhead by delaying disabling servers only
after there are no fair task around for a whole period, which means that
deadline entities are not dequeued right away on a server stop event.
However, the delay opens up a window in which a request for changing
server parameters can break per-runqueue running_bw tracking, as
reported by Yuri.
Close the problematic window by unconditionally calling dl_server_stop()
before applying the new parameters (ensuring deadline entities go
through an actual dequeue).
Fixes: cccb45d7c4 ("sched/deadline: Less agressive dl_server handling")
Reported-by: Yuri Andriaccio <yurand2000@gmail.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/20250721-upstream-fix-dlserver-lessaggressive-b4-v1-1-4ebc10c87e40@redhat.com
Pull perf fix from Borislav Petkov:
- Fix a case where the events throttling logic operates on inactive
events
* tag 'perf_urgent_for_v6.17_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Avoid undefined behavior from stopping/starting inactive events
Pull modules fix from Daniel Gomez:
"This includes a fix part of the KSPP (Kernel Self Protection Project)
to replace the deprecated and unsafe strcpy() calls in the kernel
parameter string handler and sysfs parameters for built-in modules.
Single commit, no functional changes"
* tag 'modules-6.17-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux:
params: Replace deprecated strcpy() with strscpy() and memcpy()
Pull tracing fixes from Steven Rostedt:
- Fix rtla and latency tooling pkg-config errors
If libtraceevent and libtracefs is installed, but their corresponding
'.pc' files are not installed, it reports that the libraries are
missing and confuses the developer. Instead, report that the
pkg-config files are missing and should be installed.
- Fix overflow bug of the parser in trace_get_user()
trace_get_user() uses the parsing functions to parse the user space
strings. If the parser fails due to incorrect processing, it doesn't
terminate the buffer with a nul byte. Add a "failed" flag to the
parser that gets set when parsing fails and is used to know if the
buffer is fine to use or not.
- Remove a semicolon that was at an end of a comment line
- Fix register_ftrace_graph() to unregister the pm notifier on error
The register_ftrace_graph() registers a pm notifier but there's an
error path that can exit the function without unregistering it. Since
the function returns an error, it will never be unregistered.
- Allocate and copy ftrace hash for reader of ftrace filter files
When the set_ftrace_filter or set_ftrace_notrace files are open for
read, an iterator is created and sets its hash pointer to the
associated hash that represents filtering or notrace filtering to it.
The issue is that the hash it points to can change while the
iteration is happening. All the locking used to access the tracer's
hashes are released which means those hashes can change or even be
freed. Using the hash pointed to by the iterator can cause UAF bugs
or similar.
Have the read of these files allocate and copy the corresponding
hashes and use that as that will keep them the same while the
iterator is open. This also simplifies the code as opening it for
write already does an allocate and copy, and now that the read is
doing the same, there's no need to check which way it was opened on
the release of the file, and the iterator hash can always be freed.
- Fix function graph to copy args into temp storage
The output of the function graph tracer shows both the entry and the
exit of a function. When the exit is right after the entry, it
combines the two events into one with the output of "function();",
instead of showing:
function() {
}
In order to do this, the iterator descriptor that reads the events
includes storage that saves the entry event while it peaks at the
next event in the ring buffer. The peek can free the entry event so
the iterator must store the information to use it after the peek.
With the addition of function graph tracer recording the args, where
the args are a dynamic array in the entry event, the temp storage
does not save them. This causes the args to be corrupted or even
cause a read of unsafe memory.
Add space to save the args in the temp storage of the iterator.
- Fix race between ftrace_dump and reading trace_pipe
ftrace_dump() is used when a crash occurs where the ftrace buffer
will be printed to the console. But it can also be triggered by
sysrq-z. If a sysrq-z is triggered while a task is reading trace_pipe
it can cause a race in the ftrace_dump() where it checks if the
buffer has content, then it checks if the next event is available,
and then prints the output (regardless if the next event was
available or not). Reading trace_pipe at the same time can cause it
to not be available, and this triggers a WARN_ON in the print. Move
the printing into the check if the next event exists or not
* tag 'trace-v6.17-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ftrace: Also allocate and copy hash for reading of filter files
ftrace: Fix potential warning in trace_printk_seq during ftrace_dump
fgraph: Copy args in intermediate storage with entry
trace/fgraph: Fix the warning caused by missing unregister notifier
ring-buffer: Remove redundant semicolons
tracing: Limit access to parser->buffer when trace_get_user failed
rtla: Check pkg-config install
tools/latency-collector: Check pkg-config install
When calling ftrace_dump_one() concurrently with reading trace_pipe,
a WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race
condition.
The issue occurs because:
CPU0 (ftrace_dump) CPU1 (reader)
echo z > /proc/sysrq-trigger
!trace_empty(&iter)
trace_iterator_reset(&iter) <- len = size = 0
cat /sys/kernel/tracing/trace_pipe
trace_find_next_entry_inc(&iter)
__find_next_entry
ring_buffer_empty_cpu <- all empty
return NULL
trace_printk_seq(&iter.seq)
WARN_ON_ONCE(s->seq.len >= s->seq.size)
In the context between trace_empty() and trace_find_next_entry_inc()
during ftrace_dump, the ring buffer data was consumed by other readers.
This caused trace_find_next_entry_inc to return NULL, failing to populate
`iter.seq`. At this point, due to the prior trace_iterator_reset, both
`iter.seq.len` and `iter.seq.size` were set to 0. Since they are equal,
the WARN_ON_ONCE condition is triggered.
Move the trace_printk_seq() into the if block that checks to make sure the
return value of trace_find_next_entry_inc() is non-NULL in
ftrace_dump_one(), ensuring the 'iter.seq' is properly populated before
subsequent operations.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ingo Molnar <mingo@elte.hu>
Link: https://lore.kernel.org/20250822033343.3000289-1-wutengda@huaweicloud.com
Fixes: d769041f86 ("ring_buffer: implement new locking")
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The output of the function graph tracer has two ways to display its
entries. One way for leaf functions with no events recorded within them,
and the other is for functions with events recorded inside it. As function
graph has an entry and exit event, to simplify the output of leaf
functions it combines the two, where as non leaf functions are separate:
2) | invoke_rcu_core() {
2) | raise_softirq() {
2) 0.391 us | __raise_softirq_irqoff();
2) 1.191 us | }
2) 2.086 us | }
The __raise_softirq_irqoff() function above is really two events that were
merged into one. Otherwise it would have looked like:
2) | invoke_rcu_core() {
2) | raise_softirq() {
2) | __raise_softirq_irqoff() {
2) 0.391 us | }
2) 1.191 us | }
2) 2.086 us | }
In order to do this merge, the reading of the trace output file needs to
look at the next event before printing. But since the pointer to the event
is on the ring buffer, it needs to save the entry event before it looks at
the next event as the next event goes out of focus as soon as a new event
is read from the ring buffer. After it reads the next event, it will print
the entry event with either the '{' (non leaf) or ';' and timestamps (leaf).
The iterator used to read the trace file has storage for this event. The
problem happens when the function graph tracer has arguments attached to
the entry event as the entry now has a variable length "args" field. This
field only gets set when funcargs option is used. But the args are not
recorded in this temp data and garbage could be printed. The entry field
is copied via:
data->ent = *curr;
Where "curr" is the entry field. But this method only saves the non
variable length fields from the structure.
Add a helper structure to the iterator data that adds the max args size to
the data storage in the iterator. Then simply copy the entire entry into
this storage (with size protection).
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/20250820195522.51d4a268@gandalf.local.home
Reported-by: Sasha Levin <sashal@kernel.org>
Tested-by: Sasha Levin <sashal@kernel.org>
Closes: https://lore.kernel.org/all/aJaxRVKverIjF4a6@lappy/
Fixes: ff5c9c576e ("ftrace: Add support for function argument to graph tracer")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
A hung task can occur during [1] LTP cgroup testing when repeatedly
mounting/unmounting perf_event and net_prio controllers with
systemd.unified_cgroup_hierarchy=1. The hang manifests in
cgroup_lock_and_drain_offline() during root destruction.
Related case:
cgroup_fj_function_perf_event cgroup_fj_function.sh perf_event
cgroup_fj_function_net_prio cgroup_fj_function.sh net_prio
Call Trace:
cgroup_lock_and_drain_offline+0x14c/0x1e8
cgroup_destroy_root+0x3c/0x2c0
css_free_rwork_fn+0x248/0x338
process_one_work+0x16c/0x3b8
worker_thread+0x22c/0x3b0
kthread+0xec/0x100
ret_from_fork+0x10/0x20
Root Cause:
CPU0 CPU1
mount perf_event umount net_prio
cgroup1_get_tree cgroup_kill_sb
rebind_subsystems // root destruction enqueues
// cgroup_destroy_wq
// kill all perf_event css
// one perf_event css A is dying
// css A offline enqueues cgroup_destroy_wq
// root destruction will be executed first
css_free_rwork_fn
cgroup_destroy_root
cgroup_lock_and_drain_offline
// some perf descendants are dying
// cgroup_destroy_wq max_active = 1
// waiting for css A to die
Problem scenario:
1. CPU0 mounts perf_event (rebind_subsystems)
2. CPU1 unmounts net_prio (cgroup_kill_sb), queuing root destruction work
3. A dying perf_event CSS gets queued for offline after root destruction
4. Root destruction waits for offline completion, but offline work is
blocked behind root destruction in cgroup_destroy_wq (max_active=1)
Solution:
Split cgroup_destroy_wq into three dedicated workqueues:
cgroup_offline_wq – Handles CSS offline operations
cgroup_release_wq – Manages resource release
cgroup_free_wq – Performs final memory deallocation
This separation eliminates blocking in the CSS free path while waiting for
offline operations to complete.
[1] https://github.com/linux-test-project/ltp/blob/master/runtest/controllers
Fixes: 334c3679ec ("cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends")
Reported-by: Gao Yingjie <gaoyingjie@uniontech.com>
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Suggested-by: Teju Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull misc fixes from Andrew Morton:
"20 hotfixes. 10 are cc:stable and the remainder address post-6.16
issues or aren't considered necessary for -stable kernels. 17 of these
fixes are for MM.
As usual, singletons all over the place, apart from a three-patch
series of KHO followup work from Pasha which is actually also a bunch
of singletons"
* tag 'mm-hotfixes-stable-2025-08-21-18-17' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/mremap: fix WARN with uffd that has remap events disabled
mm/damon/sysfs-schemes: put damos dests dir after removing its files
mm/migrate: fix NULL movable_ops if CONFIG_ZSMALLOC=m
mm/damon/core: fix damos_commit_filter not changing allow
mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn
MAINTAINERS: mark MGLRU as maintained
mm: rust: add page.rs to MEMORY MANAGEMENT - RUST
iov_iter: iterate_folioq: fix handling of offset >= folio size
selftests/damon: fix selftests by installing drgn related script
.mailmap: add entry for Easwar Hariharan
selftests/mm: add test for invalid multi VMA operations
mm/mremap: catch invalid multi VMA moves earlier
mm/mremap: allow multi-VMA move when filesystem uses thp_get_unmapped_area
mm/damon/core: fix commit_ops_filters by using correct nth function
tools/testing: add linux/args.h header and fix radix, VMA tests
mm/debug_vm_pgtable: clear page table entries at destroy_args()
squashfs: fix memory leak in squashfs_fill_super
kho: warn if KHO is disabled due to an error
kho: mm: don't allow deferred struct page with KHO
kho: init new_physxa->phys_bits to fix lockdep
Pull cgroup fixes from Tejun Heo:
- Fix NULL de-ref in css_rstat_exit() which could happen after
allocation failure
- Fix a cpuset partition handling bug and a couple other misc issues
- Doc spelling fix
* tag 'cgroup-for-6.17-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
docs: cgroup: fixed spelling mistakes in documentation
cgroup: avoid null de-ref in css_rstat_exit()
cgroup/cpuset: Remove the unnecessary css_get/put() in cpuset_partition_write()
cgroup/cpuset: Fix a partition error with CPU hotplug
cgroup/cpuset: Use static_branch_enable_cpuslocked() on cpusets_insane_config_key
Pull sched_ext fixes from Tejun Heo:
- Fix a subtle bug during SCX enabling where a dead task skips init
but doesn't skip sched class switch leading to invalid task state
transition warning
- Cosmetic fix in selftests
* tag 'sched_ext-for-6.17-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
selftests/sched_ext: Remove duplicate sched.h header
sched/ext: Fix invalid task state transitions on class switch
Pull probes fix from Masami Hiramatsu:
"Sanitize wildcard for fprobe event name
Fprobe event accepts wildcards for the target functions, but unless
the user specifies its event name, it makes an event with the
wildcards. Replace the wildcard '*' with the underscore '_'"
* tag 'probes-fixes-v6.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: fprobe-event: Sanitize wildcard for fprobe event name
Fprobe event accepts wildcards for the target functions, but unless user
specifies its event name, it makes an event with the wildcards.
/sys/kernel/tracing # echo 'f mutex*' >> dynamic_events
/sys/kernel/tracing # cat dynamic_events
f:fprobes/mutex*__entry mutex*
/sys/kernel/tracing # ls events/fprobes/
enable filter mutex*__entry
To fix this, replace the wildcard ('*') with an underscore.
Link: https://lore.kernel.org/all/175535345114.282990.12294108192847938710.stgit@devnote2/
Fixes: 334e5519c3 ("tracing/probes: Add fprobe events for tracing function entry and exit.")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
This warning was triggered during testing on v6.16:
notifier callback ftrace_suspend_notifier_call already registered
WARNING: CPU: 2 PID: 86 at kernel/notifier.c:23 notifier_chain_register+0x44/0xb0
...
Call Trace:
<TASK>
blocking_notifier_chain_register+0x34/0x60
register_ftrace_graph+0x330/0x410
ftrace_profile_write+0x1e9/0x340
vfs_write+0xf8/0x420
? filp_flush+0x8a/0xa0
? filp_close+0x1f/0x30
? do_dup2+0xaf/0x160
ksys_write+0x65/0xe0
do_syscall_64+0xa4/0x260
entry_SYSCALL_64_after_hwframe+0x77/0x7f
When writing to the function_profile_enabled interface, the notifier was
not unregistered after start_graph_tracing failed, causing a warning the
next time function_profile_enabled was written.
Fixed by adding unregister_pm_notifier in the exception path.
Link: https://lore.kernel.org/20250818073332.3890629-1-yeweihua4@huawei.com
Fixes: 4a2b8dda3f ("tracing/function-graph-tracer: fix a regression while suspend to disk")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ye Weihua <yeweihua4@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When the length of the string written to set_ftrace_filter exceeds
FTRACE_BUFF_MAX, the following KASAN alarm will be triggered:
BUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0
Read of size 1 at addr ffff0000d00bd5ba by task ash/165
CPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty
Hardware name: linux,dummy-virt (DT)
Call trace:
show_stack+0x34/0x50 (C)
dump_stack_lvl+0xa0/0x158
print_address_description.constprop.0+0x88/0x398
print_report+0xb0/0x280
kasan_report+0xa4/0xf0
__asan_report_load1_noabort+0x20/0x30
strsep+0x18c/0x1b0
ftrace_process_regex.isra.0+0x100/0x2d8
ftrace_regex_release+0x484/0x618
__fput+0x364/0xa58
____fput+0x28/0x40
task_work_run+0x154/0x278
do_notify_resume+0x1f0/0x220
el0_svc+0xec/0xf0
el0t_64_sync_handler+0xa0/0xe8
el0t_64_sync+0x1ac/0x1b0
The reason is that trace_get_user will fail when processing a string
longer than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0.
Then an OOB access will be triggered in ftrace_regex_release->
ftrace_process_regex->strsep->strpbrk. We can solve this problem by
limiting access to parser->buffer when trace_get_user failed.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250813040232.1344527-1-pulehui@huaweicloud.com
Fixes: 8c9af478c0 ("ftrace: Handle commands when closing set_ftrace_filter file")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Patch series "Several KHO Hotfixes".
Three unrelated fixes for Kexec Handover.
This patch (of 3):
Lockdep shows the following warning:
INFO: trying to register non-static key. The code is fine but needs
lockdep annotation, or maybe you didn't initialize this object before use?
turning off the locking correctness validator.
[<ffffffff810133a6>] dump_stack_lvl+0x66/0xa0
[<ffffffff8136012c>] assign_lock_key+0x10c/0x120
[<ffffffff81358bb4>] register_lock_class+0xf4/0x2f0
[<ffffffff813597ff>] __lock_acquire+0x7f/0x2c40
[<ffffffff81360cb0>] ? __pfx_hlock_conflict+0x10/0x10
[<ffffffff811707be>] ? native_flush_tlb_global+0x8e/0xa0
[<ffffffff8117096e>] ? __flush_tlb_all+0x4e/0xa0
[<ffffffff81172fc2>] ? __kernel_map_pages+0x112/0x140
[<ffffffff813ec327>] ? xa_load_or_alloc+0x67/0xe0
[<ffffffff81359556>] lock_acquire+0xe6/0x280
[<ffffffff813ec327>] ? xa_load_or_alloc+0x67/0xe0
[<ffffffff8100b9e0>] _raw_spin_lock+0x30/0x40
[<ffffffff813ec327>] ? xa_load_or_alloc+0x67/0xe0
[<ffffffff813ec327>] xa_load_or_alloc+0x67/0xe0
[<ffffffff813eb4c0>] kho_preserve_folio+0x90/0x100
[<ffffffff813ebb7f>] __kho_finalize+0xcf/0x400
[<ffffffff813ebef4>] kho_finalize+0x34/0x70
This is becase xa has its own lock, that is not initialized in
xa_load_or_alloc.
Modifiy __kho_preserve_order(), to properly call
xa_init(&new_physxa->phys_bits);
Link: https://lkml.kernel.org/r/20250808201804.772010-2-pasha.tatashin@soleen.com
Fixes: fc33e4b44b ("kexec: enable KHO support for memory preservation")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baoquan He <bhe@redhat.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Coiby Xu <coxu@redhat.com>
Cc: Dave Vasilevsky <dave@vasilevsky.ca>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull vfs fixes from Christian Brauner:
- Fix two memory leaks in pidfs
- Prevent changing the idmapping of an already idmapped mount without
OPEN_TREE_CLONE through open_tree_attr()
- Don't fail listing extended attributes in kernfs when no extended
attributes are set
- Fix the return value in coredump_parse()
- Fix the error handling for unbuffered writes in netfs
- Fix broken data integrity guarantees for O_SYNC writes via iomap
- Fix UAF in __mark_inode_dirty()
- Keep inode->i_blkbits constant in fuse
- Fix coredump selftests
- Fix get_unused_fd_flags() usage in do_handle_open()
- Rename EXPORT_SYMBOL_GPL_FOR_MODULES to EXPORT_SYMBOL_FOR_MODULES
- Fix use-after-free in bh_read()
- Fix incorrect lflags value in the move_mount() syscall
* tag 'vfs-6.17-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
signal: Fix memory leak for PIDFD_SELF* sentinels
kernfs: don't fail listing extended attributes
coredump: Fix return value in coredump_parse()
fs/buffer: fix use-after-free when call bh_read() helper
pidfs: Fix memory leak in pidfd_info()
netfs: Fix unbuffered write error handling
fhandle: do_handle_open() should get FD with user flags
module: Rename EXPORT_SYMBOL_GPL_FOR_MODULES to EXPORT_SYMBOL_FOR_MODULES
fs: fix incorrect lflags value in the move_mount syscall
selftests/coredump: Remove the read() that fails the test
fuse: keep inode->i_blkbits constant
iomap: Fix broken data integrity guarantees for O_SYNC writes
selftests/mount_setattr: add smoke tests for open_tree_attr(2) bug
open_tree_attr: do not allow id-mapping changes without OPEN_TREE_CLONE
fs: writeback: fix use-after-free in __mark_inode_dirty()
Commit f08d0c3a71 ("pidfd: add PIDFD_SELF* sentinels to refer to own
thread/process") introduced a leak by acquiring a pid reference through
get_task_pid(), which increments pid->count but never drops it with
put_pid().
As a result, kmemleak reports unreferenced pid objects after running
tools/testing/selftests/pidfd/pidfd_test, for example:
unreferenced object 0xff1100206757a940 (size 160):
comm "pidfd_test", pid 16965, jiffies 4294853028
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 fd 57 50 04 .............WP.
5e 44 00 00 00 00 00 00 18 de 34 17 01 00 11 ff ^D........4.....
backtrace (crc cd8844d4):
kmem_cache_alloc_noprof+0x2f4/0x3f0
alloc_pid+0x54/0x3d0
copy_process+0xd58/0x1740
kernel_clone+0x99/0x3b0
__do_sys_clone3+0xbe/0x100
do_syscall_64+0x7b/0x2c0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fix this by calling put_pid() after do_pidfd_send_signal() returns.
Fixes: f08d0c3a71 ("pidfd: add PIDFD_SELF* sentinels to refer to own thread/process")
Signed-off-by: Adrian Huang (Lenovo) <adrianhuang0701@gmail.com>
Link: https://lore.kernel.org/20250818134310.12273-1-adrianhuang0701@gmail.com
Tested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull locking fixes from Borislav Petkov:
- Make sure sanity checks down in the mutex lock path happen on the
correct type of task so that they don't trigger falsely
- Use the write unsafe user access pairs when writing a futex value to
prevent an error on PowerPC which does user read and write accesses
differently
* tag 'locking_urgent_for_v6.17_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking: Fix __clear_task_blocked_on() warning from __ww_mutex_wound() path
futex: Use user_write_access_begin/_end() in futex_put_value()
Calling pmu->start()/stop() on perf events in PERF_EVENT_STATE_OFF can
leave event->hw.idx at -1. When PMU drivers later attempt to use this
negative index as a shift exponent in bitwise operations, it leads to UBSAN
shift-out-of-bounds reports.
The issue is a logical flaw in how event groups handle throttling when some
members are intentionally disabled. Based on the analysis and the
reproducer provided by Mark Rutland (this issue on both arm64 and x86-64).
The scenario unfolds as follows:
1. A group leader event is configured with a very aggressive sampling
period (e.g., sample_period = 1). This causes frequent interrupts and
triggers the throttling mechanism.
2. A child event in the same group is created in a disabled state
(.disabled = 1). This event remains in PERF_EVENT_STATE_OFF.
Since it hasn't been scheduled onto the PMU, its event->hw.idx remains
initialized at -1.
3. When throttling occurs, perf_event_throttle_group() and later
perf_event_unthrottle_group() iterate through all siblings, including
the disabled child event.
4. perf_event_throttle()/unthrottle() are called on this inactive child
event, which then call event->pmu->start()/stop().
5. The PMU driver receives the event with hw.idx == -1 and attempts to
use it as a shift exponent. e.g., in macros like PMCNTENSET(idx),
leading to the UBSAN report.
The throttling mechanism attempts to start/stop events that are not
actively scheduled on the hardware.
Move the state check into perf_event_throttle()/perf_event_unthrottle() so
that inactive events are skipped entirely. This ensures only active events
with a valid hw.idx are processed, preventing undefined behavior and
silencing UBSAN warnings. The corrected check ensures true before
proceeding with PMU operations.
The problem can be reproduced with the syzkaller reproducer:
Fixes: 9734e25fbf ("perf: Fix the throttle logic for a group")
Signed-off-by: Yunseong Kim <ysk@kzalloc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20250812181046.292382-2-ysk@kzalloc.com
When running an XDP bpf_prog on the remote CPU in cpumap code
then we must disable the direct return optimization that
xdp_return can perform for mem_type page_pool. This optimization
assumes code is still executing under RX-NAPI of the original
receiving CPU, which isn't true on this remote CPU.
The cpumap code already disabled this via helpers
xdp_set_return_frame_no_direct() and xdp_clear_return_frame_no_direct(),
but the scope didn't include xdp_do_flush().
When doing XDP_REDIRECT towards e.g devmap this causes the
function bq_xmit_all() to run with direct return optimization
enabled. This can lead to hard to find bugs. The issue
only happens when bq_xmit_all() cannot ndo_xdp_xmit all
frames and them frees them via xdp_return_frame_rx_napi().
Fix by expanding scope to include xdp_do_flush(). This was found
by Dragos Tatulea.
Fixes: 11941f8a85 ("bpf: cpumap: Implement generic cpumap")
Reported-by: Dragos Tatulea <dtatulea@nvidia.com>
Reported-by: Chris Arges <carges@cloudflare.com>
Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Chris Arges <carges@cloudflare.com>
Link: https://patch.msgid.link/175519587755.3008742.1088294435150406835.stgit@firesoul
Pull networking fixes from Paolo Abeni:
"Including fixes from Netfilter and IPsec.
Current release - regressions:
- netfilter: nft_set_pipapo:
- don't return bogus extension pointer
- fix null deref for empty set
Current release - new code bugs:
- core: prevent deadlocks when enabling NAPIs with mixed kthread
config
- eth: netdevsim: Fix wild pointer access in nsim_queue_free().
Previous releases - regressions:
- page_pool: allow enabling recycling late, fix false positive
warning
- sched: ets: use old 'nbands' while purging unused classes
- xfrm:
- restore GSO for SW crypto
- bring back device check in validate_xmit_xfrm
- tls: handle data disappearing from under the TLS ULP
- ptp: prevent possible ABBA deadlock in ptp_clock_freerun()
- eth:
- bnxt: fill data page pool with frags if PAGE_SIZE > BNXT_RX_PAGE_SIZE
- hv_netvsc: fix panic during namespace deletion with VF
Previous releases - always broken:
- netfilter: fix refcount leak on table dump
- vsock: do not allow binding to VMADDR_PORT_ANY
- sctp: linearize cloned gso packets in sctp_rcv
- eth:
- hibmcge: fix the division by zero issue
- microchip: fix KSZ8863 reset problem"
* tag 'net-6.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (54 commits)
net: usb: asix_devices: add phy_mask for ax88772 mdio bus
net: kcm: Fix race condition in kcm_unattach()
selftests: net/forwarding: test purge of active DWRR classes
net/sched: ets: use old 'nbands' while purging unused classes
bnxt: fill data page pool with frags if PAGE_SIZE > BNXT_RX_PAGE_SIZE
netdevsim: Fix wild pointer access in nsim_queue_free().
net: mctp: Fix bad kfree_skb in bind lookup test
netfilter: nf_tables: reject duplicate device on updates
ipvs: Fix estimator kthreads preferred affinity
netfilter: nft_set_pipapo: fix null deref for empty set
selftests: tls: test TCP stealing data from under the TLS socket
tls: handle data disappearing from under the TLS ULP
ptp: prevent possible ABBA deadlock in ptp_clock_freerun()
ixgbe: prevent from unwanted interface name changes
devlink: let driver opt out of automatic phys_port_name generation
net: prevent deadlocks when enabling NAPIs with mixed kthread config
net: update NAPI threaded config even for disabled NAPIs
selftests: drv-net: don't assume device has only 2 queues
docs: Fix name for net.ipv4.udp_child_hash_entries
riscv: dts: thead: Add APB clocks for TH1520 GMACs
...
When CONFIG_DMA_DIRECT_REMAP is enabled, atomic pool pages are
remapped via dma_common_contiguous_remap() using the supplied
pgprot. Currently, the mapping uses
pgprot_dmacoherent(PAGE_KERNEL), which leaves the memory encrypted
on systems with memory encryption enabled (e.g., ARM CCA Realms).
This can cause the DMA layer to fail or crash when accessing the
memory, as the underlying physical pages are not configured as
expected.
Fix this by requesting a decrypted mapping in the vmap() call:
pgprot_decrypted(pgprot_dmacoherent(PAGE_KERNEL))
This ensures that atomic pool memory is consistently mapped
unencrypted.
Cc: stable@vger.kernel.org
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250811181759.998805-1-sdonthineni@nvidia.com
The __clear_task_blocked_on() helper added a number of sanity
checks ensuring we hold the mutex wait lock and that the task
we are clearing blocked_on pointer (if set) matches the mutex.
However, there is an edge case in the _ww_mutex_wound() logic
where we need to clear the blocked_on pointer for the task that
owns the mutex, not the task that is waiting on the mutex.
For this case the sanity checks aren't valid, so handle this
by allowing a NULL lock to skip the additional checks.
K Prateek Nayak and Maarten Lankhorst also pointed out that in
this case where we don't hold the owner's mutex wait_lock, we
need to be a bit more careful using READ_ONCE/WRITE_ONCE in both
the __clear_task_blocked_on() and __set_task_blocked_on()
implementations to avoid accidentally tripping WARN_ONs if two
instances race. So do that here as well.
This issue was easier to miss, I realized, as the test-ww_mutex
driver only exercises the wait-die class of ww_mutexes. I've
sent a patch[1] to address this so the logic will be easier to
test.
[1]: https://lore.kernel.org/lkml/20250801023358.562525-2-jstultz@google.com/
Fixes: a4f0b6fef4 ("locking/mutex: Add p->blocked_on wrappers for correctness checks")
Closes: https://lore.kernel.org/lkml/68894443.a00a0220.26d0e1.0015.GAE@google.com/
Reported-by: syzbot+602c4720aed62576cd79@syzkaller.appspotmail.com
Reported-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://lore.kernel.org/r/20250805001026.2247040-1-jstultz@google.com
The estimator kthreads' affinity are defined by sysctl overwritten
preferences and applied through a plain call to the scheduler's affinity
API.
However since the introduction of managed kthreads preferred affinity,
such a practice shortcuts the kthreads core code which eventually
overwrites the target to the default unbound affinity.
Fix this with using the appropriate kthread's API.
Fixes: d1a8919758 ("kthread: Default affine kthread to its preferred NUMA node")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
When enabling a sched_ext scheduler, we may trigger invalid task state
transitions, resulting in warnings like the following (which can be
easily reproduced by running the hotplug selftest in a loop):
sched_ext: Invalid task state transition 0 -> 3 for fish[770]
WARNING: CPU: 18 PID: 787 at kernel/sched/ext.c:3862 scx_set_task_state+0x7c/0xc0
...
RIP: 0010:scx_set_task_state+0x7c/0xc0
...
Call Trace:
<TASK>
scx_enable_task+0x11f/0x2e0
switching_to_scx+0x24/0x110
scx_enable.isra.0+0xd14/0x13d0
bpf_struct_ops_link_create+0x136/0x1a0
__sys_bpf+0x1edd/0x2c30
__x64_sys_bpf+0x21/0x30
do_syscall_64+0xbb/0x370
entry_SYSCALL_64_after_hwframe+0x77/0x7f
This happens because we skip initialization for tasks that are already
dead (with their usage counter set to zero), but we don't exclude them
during the scheduling class transition phase.
Fix this by also skipping dead tasks during class swiching, preventing
invalid task state transitions.
Fixes: a8532fac7b ("sched_ext: TASK_DEAD tasks must be switched into SCX on ops_enable")
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Commit cec199c5e3 ("futex: Implement FUTEX2_NUMA") introduced the
futex_put_value() helper to write a value to the given user
address.
However, it uses user_read_access_begin() before the write. For
architectures that differentiate between read and write accesses, like
PowerPC, futex_put_value() fails with -EFAULT.
Fix that by using the user_write_access_begin/user_write_access_end() pair
instead.
Fixes: cec199c5e3 ("futex: Implement FUTEX2_NUMA")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250811141147.322261-1-longman@redhat.com
RCU re-initializes the deferred QS irq work everytime before attempting
to queue it. However there are situations where the irq work is
attempted to be queued even though it is already queued. In that case
re-initializing messes-up with the irq work queue that is about to be
handled.
The chances for that to happen are higher when the architecture doesn't
support self-IPIs and irq work are then all lazy, such as with the
following sequence:
1) rcu_read_unlock() is called when IRQs are disabled and there is a
grace period involving blocked tasks on the node. The irq work
is then initialized and queued.
2) The related tasks are unblocked and the CPU quiescent state
is reported. rdp->defer_qs_iw_pending is reset to DEFER_QS_IDLE,
allowing the irq work to be requeued in the future (note the previous
one hasn't fired yet).
3) A new grace period starts and the node has blocked tasks.
4) rcu_read_unlock() is called when IRQs are disabled again. The irq work
is re-initialized (but it's queued! and its node is cleared) and
requeued. Which means it's requeued to itself.
5) The irq work finally fires with the tick. But since it was requeued
to itself, it loops and hangs.
Fix this with initializing the irq work only once before the CPU boots.
Fixes: b41642c877 ("rcu: Fix rcu_read_unlock() deadloop due to IRQ work")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202508071303.c1134cce-lkp@intel.com
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>
Pull smp fixes from Borislav Petkov:
- Remove an obsolete comment and fix spelling
* tag 'smp_urgent_for_v6.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu: Remove obsolete comment from takedown_cpu()
smp: Fix spelling in on_each_cpu_cond_mask()'s doc-comment
Pull irq fixes from Borislav Petkov:
- Fix a wrong ioremap size in mvebu-gicp
- Remove yet another compile-test case for a driver which needs an
additional dependency
- Fix a lock inversion scenario in the IRQ unit test suite
- Remove an impossible flag situation in gic-v5
- Do not iounmap resources in gic-v5 which are managed by devm
- Make sure stale, left-over interrupts in mvebu-gicp are cleared on
driver init
- Fix a reference counting mishap in msi-lib
- Fix a dereference-before-null-ptr-check case in the riscv-imsic
irqchip driver
* tag 'irq_urgent_for_v6.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/mvebu-gicp: Use resource_size() for ioremap()
irqchip: Build IMX_MU_MSI only on ARM
genirq/test: Resolve irq lock inversion warnings
irqchip/gic-v5: Remove IRQD_RESEND_WHEN_IN_PROGRESS for ITS IRQs
irqchip/gic-v5: iwb: Fix iounmap probe failure path
irqchip/mvebu-gicp: Clear pending interrupts on init
irqchip/msi-lib: Fix fwnode refcount in msi_lib_irq_domain_select()
irqchip/riscv-imsic: Don't dereference before NULL pointer check
Pull locking fix from Borislav Petkov:
- Prevent a futex hash leak due to different mm lifetimes
* tag 'locking_urgent_for_v6.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Move futex cleanup to __mmdrop()
css_rstat_exit() may be called asynchronously in scenarios where preceding
calls to css_rstat_init() have not completed. One such example is this
sequence below:
css_create(...)
{
...
init_and_link_css(css, ...);
err = percpu_ref_init(...);
if (err)
goto err_free_css;
err = cgroup_idr_alloc(...);
if (err)
goto err_free_css;
err = css_rstat_init(css, ...);
if (err)
goto err_free_css;
...
err_free_css:
INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
return ERR_PTR(err);
}
If any of the three goto jumps are taken, async cleanup will begin and
css_rstat_exit() will be invoked on an uninitialized css->rstat_cpu.
Avoid accessing the unitialized field by returning early in
css_rstat_exit() if this is the case.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Suggested-by: Michal Koutný <mkoutny@suse.com>
Fixes: 5da3bfa029 ("cgroup: use separate rstat trees for each subsystem")
Cc: stable@vger.kernel.org # v6.16
Reported-by: syzbot+8d052e8b99e40bc625ed@syzkaller.appspotmail.com
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Tejun Heo <tj@kernel.org>
The css_get/put() calls in cpuset_partition_write() are unnecessary as
an active reference of the kernfs node will be taken which will prevent
its removal and guarantee the existence of the css. Only the online
check is needed.
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
It was found during testing that an invalid leaf partition with an
empty effective exclusive CPU list can become a valid empty partition
with no CPU afer an offline/online operation of an unrelated CPU. An
empty partition root is allowed in the special case that it has no
task in its cgroup and has distributed out all its CPUs to its child
partitions. That is certainly not the case here.
The problem is in the cpumask_subsets() test in the hotplug case
(update with no new mask) of update_parent_effective_cpumask() as it
also returns true if the effective exclusive CPU list is empty. Fix that
by addding the cpumask_empty() test to root out this exception case.
Also add the cpumask_empty() test in cpuset_hotplug_update_tasks()
to avoid calling update_parent_effective_cpumask() for this special case.
Fixes: 0c7f293efc ("cgroup/cpuset: Add cpuset.cpus.exclusive.effective for v2")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The following lockdep splat was observed.
[ 812.359086] ============================================
[ 812.359089] WARNING: possible recursive locking detected
[ 812.359097] --------------------------------------------
[ 812.359100] runtest.sh/30042 is trying to acquire lock:
[ 812.359105] ffffffffa7f27420 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_enable+0xe/0x20
[ 812.359131]
[ 812.359131] but task is already holding lock:
[ 812.359134] ffffffffa7f27420 (cpu_hotplug_lock){++++}-{0:0}, at: cpuset_write_resmask+0x98/0xa70
:
[ 812.359267] Call Trace:
[ 812.359272] <TASK>
[ 812.359367] cpus_read_lock+0x3c/0xe0
[ 812.359382] static_key_enable+0xe/0x20
[ 812.359389] check_insane_mems_config.part.0+0x11/0x30
[ 812.359398] cpuset_write_resmask+0x9f2/0xa70
[ 812.359411] cgroup_file_write+0x1c7/0x660
[ 812.359467] kernfs_fop_write_iter+0x358/0x530
[ 812.359479] vfs_write+0xabe/0x1250
[ 812.359529] ksys_write+0xf9/0x1d0
[ 812.359558] do_syscall_64+0x5f/0xe0
Since commit d74b27d63a ("cgroup/cpuset: Change cpuset_rwsem
and hotplug lock order"), the ordering of cpu hotplug lock
and cpuset_mutex had been reversed. That patch correctly
used the cpuslocked version of the static branch API to enable
cpusets_pre_enable_key and cpusets_enabled_key, but it didn't do the
same for cpusets_insane_config_key.
The cpusets_insane_config_key can be enabled in the
check_insane_mems_config() which is called from update_nodemask()
or cpuset_hotplug_update_tasks() with both cpu hotplug lock and
cpuset_mutex held. Deadlock can happen with a pending hotplug event that
tries to acquire the cpu hotplug write lock which will block further
cpus_read_lock() attempt from check_insane_mems_config(). Fix that by
switching to use static_branch_enable_cpuslocked().
Fixes: d74b27d63a ("cgroup/cpuset: Change cpuset_rwsem and hotplug lock order")
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
