Pull non-MM updates from Andrew Morton:
"Mainly individually changelogged singleton patches. The patch series
in this pull are:
- "lib min_heap: Improve min_heap safety, testing, and documentation"
from Kuan-Wei Chiu provides various tightenings to the min_heap
library code
- "xarray: extract __xa_cmpxchg_raw" from Tamir Duberstein preforms
some cleanup and Rust preparation in the xarray library code
- "Update reference to include/asm-<arch>" from Geert Uytterhoeven
fixes pathnames in some code comments
- "Converge on using secs_to_jiffies()" from Easwar Hariharan uses
the new secs_to_jiffies() in various places where that is
appropriate
- "ocfs2, dlmfs: convert to the new mount API" from Eric Sandeen
switches two filesystems to the new mount API
- "Convert ocfs2 to use folios" from Matthew Wilcox does that
- "Remove get_task_comm() and print task comm directly" from Yafang
Shao removes now-unneeded calls to get_task_comm() in various
places
- "squashfs: reduce memory usage and update docs" from Phillip
Lougher implements some memory savings in squashfs and performs
some maintainability work
- "lib: clarify comparison function requirements" from Kuan-Wei Chiu
tightens the sort code's behaviour and adds some maintenance work
- "nilfs2: protect busy buffer heads from being force-cleared" from
Ryusuke Konishi fixes an issues in nlifs when the fs is presented
with a corrupted image
- "nilfs2: fix kernel-doc comments for function return values" from
Ryusuke Konishi fixes some nilfs kerneldoc
- "nilfs2: fix issues with rename operations" from Ryusuke Konishi
addresses some nilfs BUG_ONs which syzbot was able to trigger
- "minmax.h: Cleanups and minor optimisations" from David Laight does
some maintenance work on the min/max library code
- "Fixes and cleanups to xarray" from Kemeng Shi does maintenance
work on the xarray library code"
* tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (131 commits)
ocfs2: use str_yes_no() and str_no_yes() helper functions
include/linux/lz4.h: add some missing macros
Xarray: use xa_mark_t in xas_squash_marks() to keep code consistent
Xarray: remove repeat check in xas_squash_marks()
Xarray: distinguish large entries correctly in xas_split_alloc()
Xarray: move forward index correctly in xas_pause()
Xarray: do not return sibling entries from xas_find_marked()
ipc/util.c: complete the kernel-doc function descriptions
gcov: clang: use correct function param names
latencytop: use correct kernel-doc format for func params
minmax.h: remove some #defines that are only expanded once
minmax.h: simplify the variants of clamp()
minmax.h: move all the clamp() definitions after the min/max() ones
minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
minmax.h: reduce the #define expansion of min(), max() and clamp()
minmax.h: update some comments
minmax.h: add whitespace around operators and after commas
nilfs2: do not update mtime of renamed directory that is not moved
nilfs2: handle errors that nilfs_prepare_chunk() may return
CREDITS: fix spelling mistake
...
Pull scheduler updates from Ingo Molnar:
"Fair scheduler (SCHED_FAIR) enhancements:
- Behavioral improvements:
- Untangle NEXT_BUDDY and pick_next_task() (Peter Zijlstra)
- Delayed-dequeue enhancements & fixes: (Vincent Guittot)
- Rename h_nr_running into h_nr_queued
- Add new cfs_rq.h_nr_runnable
- Use the new cfs_rq.h_nr_runnable
- Removed unsued cfs_rq.h_nr_delayed
- Rename cfs_rq.idle_h_nr_running into h_nr_idle
- Remove unused cfs_rq.idle_nr_running
- Rename cfs_rq.nr_running into nr_queued
- Do not try to migrate delayed dequeue task
- Fix variable declaration position
- Encapsulate set custom slice in a __setparam_fair() function
- Fixes:
- Fix race between yield_to() and try_to_wake_up() (Tianchen Ding)
- Fix CPU bandwidth limit bypass during CPU hotplug (Vishal
Chourasia)
- Cleanups:
- Clean up in migrate_degrades_locality() to improve readability
(Peter Zijlstra)
- Mark m*_vruntime() with __maybe_unused (Andy Shevchenko)
- Update comments after sched_tick() rename (Sebastian Andrzej
Siewior)
- Remove CONFIG_CFS_BANDWIDTH=n definition of cfs_bandwidth_used()
(Valentin Schneider)
Deadline scheduler (SCHED_DL) enhancements:
- Restore dl_server bandwidth on non-destructive root domain changes
(Juri Lelli)
- Correctly account for allocated bandwidth during hotplug (Juri
Lelli)
- Check bandwidth overflow earlier for hotplug (Juri Lelli)
- Clean up goto label in pick_earliest_pushable_dl_task() (John
Stultz)
- Consolidate timer cancellation (Wander Lairson Costa)
Load-balancer enhancements:
- Improve performance by prioritizing migrating eligible tasks in
sched_balance_rq() (Hao Jia)
- Do not compute NUMA Balancing stats unnecessarily during
load-balancing (K Prateek Nayak)
- Do not compute overloaded status unnecessarily during
load-balancing (K Prateek Nayak)
Generic scheduling code enhancements:
- Use READ_ONCE() in task_on_rq_queued(), to consistently use the
WRITE_ONCE() updated ->on_rq field (Harshit Agarwal)
Isolated CPUs support enhancements: (Waiman Long)
- Make "isolcpus=nohz" equivalent to "nohz_full"
- Consolidate housekeeping cpumasks that are always identical
- Remove HK_TYPE_SCHED
- Unify HK_TYPE_{TIMER|TICK|MISC} to HK_TYPE_KERNEL_NOISE
RSEQ enhancements:
- Validate read-only fields under DEBUG_RSEQ config (Mathieu
Desnoyers)
PSI enhancements:
- Fix race when task wakes up before psi_sched_switch() adjusts flags
(Chengming Zhou)
IRQ time accounting performance enhancements: (Yafang Shao)
- Define sched_clock_irqtime as static key
- Don't account irq time if sched_clock_irqtime is disabled
Virtual machine scheduling enhancements:
- Don't try to catch up excess steal time (Suleiman Souhlal)
Heterogenous x86 CPU scheduling enhancements: (K Prateek Nayak)
- Convert "sysctl_sched_itmt_enabled" to boolean
- Use guard() for itmt_update_mutex
- Move the "sched_itmt_enabled" sysctl to debugfs
- Remove x86_smt_flags and use cpu_smt_flags directly
- Use x86_sched_itmt_flags for PKG domain unconditionally
Debugging code & instrumentation enhancements:
- Change need_resched warnings to pr_err() (David Rientjes)
- Print domain name in /proc/schedstat (K Prateek Nayak)
- Fix value reported by hot tasks pulled in /proc/schedstat (Peter
Zijlstra)
- Report the different kinds of imbalances in /proc/schedstat
(Swapnil Sapkal)
- Move sched domain name out of CONFIG_SCHED_DEBUG (Swapnil Sapkal)
- Update Schedstat version to 17 (Swapnil Sapkal)"
* tag 'sched-core-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits)
rseq: Fix rseq unregistration regression
psi: Fix race when task wakes up before psi_sched_switch() adjusts flags
sched, psi: Don't account irq time if sched_clock_irqtime is disabled
sched: Don't account irq time if sched_clock_irqtime is disabled
sched: Define sched_clock_irqtime as static key
sched/fair: Do not compute overloaded status unnecessarily during lb
sched/fair: Do not compute NUMA Balancing stats unnecessarily during lb
x86/topology: Use x86_sched_itmt_flags for PKG domain unconditionally
x86/topology: Remove x86_smt_flags and use cpu_smt_flags directly
x86/itmt: Move the "sched_itmt_enabled" sysctl to debugfs
x86/itmt: Use guard() for itmt_update_mutex
x86/itmt: Convert "sysctl_sched_itmt_enabled" to boolean
sched/core: Prioritize migrating eligible tasks in sched_balance_rq()
sched/debug: Change need_resched warnings to pr_err
sched/fair: Encapsulate set custom slice in a __setparam_fair() function
sched: Fix race between yield_to() and try_to_wake_up()
docs: Update Schedstat version to 17
sched/stats: Print domain name in /proc/schedstat
sched: Move sched domain name out of CONFIG_SCHED_DEBUG
sched: Report the different kinds of imbalances in /proc/schedstat
...
Pull execve updates from Kees Cook: - fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case (Tycho Andersen, Kees Cook) - binfmt_misc: Fix comment typos (Christophe JAILLET) - move empty argv[0] warning closer to actual logic (Nir Lichtman) - remove legacy custom binfmt modules autoloading (Nir Lichtman) - Make sure set_task_comm() always NUL-terminates - binfmt_flat: Fix integer overflow bug on 32 bit systems (Dan Carpenter) - coredump: Do not lock when copying "comm" - MAINTAINERS: add auxvec.h and set myself as maintainer * tag 'execve-v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: binfmt_flat: Fix integer overflow bug on 32 bit systems selftests/exec: add a test for execveat()'s comm exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case exec: Make sure task->comm is always NUL-terminated exec: remove legacy custom binfmt modules autoloading exec: move warning of null argv to be next to the relevant code fs: binfmt: Fix a typo MAINTAINERS: exec: Mark Kees as maintainer MAINTAINERS: exec: Add auxvec.h UAPI coredump: Do not lock during 'comm' reporting
Delay accounting can now calculate the average delay of processes, detect
the overall system load, and also record the 'delay max' to identify
potential abnormal delays. However, 'delay min' can help us identify
another useful delay peak. By comparing the difference between 'delay
max' and 'delay min', we can understand the optimization space for
latency, providing a reference for the optimization of latency
performance.
Use case
=========
bash-4.4# ./getdelays -d -t 242
print delayacct stats ON
TGID 242
CPU count real total virtual total delay total delay average delay max delay min
39 156000000 156576579 2111069 0.054ms 0.212296ms 0.031307ms
IO count delay total delay average delay max delay min
0 0 0.000ms 0.000000ms 0.000000ms
SWAP count delay total delay average delay max delay min
0 0 0.000ms 0.000000ms 0.000000ms
RECLAIM count delay total delay average delay max delay min
0 0 0.000ms 0.000000ms 0.000000ms
THRASHING count delay total delay average delay max delay min
0 0 0.000ms 0.000000ms 0.000000ms
COMPACT count delay total delay average delay max delay min
0 0 0.000ms 0.000000ms 0.000000ms
WPCOPY count delay total delay average delay max delay min
156 11215873 0.072ms 0.207403ms 0.033913ms
IRQ count delay total delay average delay max delay min
0 0 0.000ms 0.000000ms 0.000000ms
Link: https://lkml.kernel.org/r/20241220173105906EOdsPhzjMLYNJJBqgz1ga@zte.com.cn
Co-developed-by: Wang Yong <wang.yong12@zte.com.cn>
Signed-off-by: Wang Yong <wang.yong12@zte.com.cn>
Co-developed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Co-developed-by: Kun Jiang <jiang.kun2@zte.com.cn>
Signed-off-by: Kun Jiang <jiang.kun2@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Peilin He <he.peilin@zte.com.cn>
Cc: tuqiang <tu.qiang35@zte.com.cn>
Cc: ye xingchen <ye.xingchen@zte.com.cn>
Cc: Yunkai Zhang <zhang.yunkai@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Introduce the use cases of delay max, which can help quickly detect
potential abnormal delays in the system and record the types and specific
details of delay spikes.
Problem
========
Delay accounting can track the average delay of processes to show
system workload. However, when a process experiences a significant
delay, maybe a delay spike, which adversely affects performance,
getdelays can only display the average system delay over a period
of time. Yet, average delay is unhelpful for diagnosing delay peak.
It is not even possible to determine which type of delay has spiked,
as this information might be masked by the average delay.
Solution
=========
the 'delay max' can display delay peak since the system's startup,
which can record potential abnormal delays over time, including
the type of delay and the maximum delay. This is helpful for
quickly identifying crash caused by delay.
Use case
=========
bash# ./getdelays -d -p 244
print delayacct stats ON
PID 244
CPU count real total virtual total delay total delay average delay max
68 192000000 213676651 705643 0.010ms 0.306381ms
IO count delay total delay average delay max
0 0 0.000ms 0.000000ms
SWAP count delay total delay average delay max
0 0 0.000ms 0.000000ms
RECLAIM count delay total delay average delay max
0 0 0.000ms 0.000000ms
THRASHING count delay total delay average delay max
0 0 0.000ms 0.000000ms
COMPACT count delay total delay average delay max
0 0 0.000ms 0.000000ms
WPCOPY count delay total delay average delay max
235 15648284 0.067ms 0.263842ms
IRQ count delay total delay average delay max
0 0 0.000ms 0.000000ms
[wang.yaxin@zte.com.cn: update docs and fix some spelling errors]
Link: https://lkml.kernel.org/r/20241213192700771XKZ8H30OtHSeziGqRVMs0@zte.com.cn
Link: https://lkml.kernel.org/r/20241203164848805CS62CQPQWG9GLdQj2_BxS@zte.com.cn
Co-developed-by: Wang Yong <wang.yong12@zte.com.cn>
Signed-off-by: Wang Yong <wang.yong12@zte.com.cn>
Co-developed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Co-developed-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Kun Jiang <jiang.kun2@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Peilin He <he.peilin@zte.com.cn>
Cc: tuqiang <tu.qiang35@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: ye xingchen <ye.xingchen@zte.com.cn>
Cc: Yunkai Zhang <zhang.yunkai@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Before commit:
f5d39b020809 ("freezer,sched: Rewrite core freezer logic")
the frozen task stat was reported as 'D' in cgroup v1.
However, after rewriting the core freezer logic, the frozen task stat is
reported as 'R'. This is confusing, especially when a task with stat of
'S' is frozen.
This bug can be reproduced with these steps:
$ cd /sys/fs/cgroup/freezer/
$ mkdir test
$ sleep 1000 &
[1] 739 // task whose stat is 'S'
$ echo 739 > test/cgroup.procs
$ echo FROZEN > test/freezer.state
$ ps -aux | grep 739
root 739 0.1 0.0 8376 1812 pts/0 R 10:56 0:00 sleep 1000
As shown above, a task whose stat is 'S' was changed to 'R' when it was
frozen.
To solve this regression, simply maintain the same reported state as
before the rewrite.
[ mingo: Enhanced the changelog and comments ]
Fixes: f5d39b020809 ("freezer,sched: Rewrite core freezer logic")
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Koutný <mkoutny@suse.com>
Link: https://lore.kernel.org/r/20241217004818.3200515-1-chenridong@huaweicloud.com
In /proc/schedstat, lb_hot_gained reports the number hot tasks pulled
during load balance. This value is incremented in can_migrate_task()
if the task is migratable and hot. After incrementing the value,
load balancer can still decide not to migrate this task leading to wrong
accounting. Fix this by incrementing stats when hot tasks are detached.
This issue only exists in detach_tasks() where we can decide to not
migrate hot task even if it is migratable. However, in detach_one_task(),
we migrate it unconditionally.
[Swapnil: Handled the case where nr_failed_migrations_hot was not accounted properly and wrote commit log]
Fixes: d31980846f96 ("sched: Move up affinity check to mitigate useless redoing overhead")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reported-by: "Gautham R. Shenoy" <gautham.shenoy@amd.com>
Not-yet-signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241220063224.17767-2-swapnil.sapkal@amd.com
Using strscpy() meant that the final character in task->comm may be non-NUL for a moment before the "string too long" truncation happens. Instead of adding a new use of the ambiguous strncpy(), we'd want to use memtostr_pad() which enforces being able to check at compile time that sizes are sensible, but this requires being able to see string buffer lengths. Instead of trying to inline __set_task_comm() (which needs to call trace and perf functions), just open-code it. But to make sure we're always safe, add compile-time checking like we already do for get_task_comm(). Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Kees Cook <kees@kernel.org>
dlserver can get dequeued during a dlserver pick_task due to the delayed
deueue feature and this can lead to issues with dlserver logic as it
still thinks that dlserver is on the runqueue. The dlserver throttling
and replenish logic gets confused and can lead to double enqueue of
dlserver.
Double enqueue of dlserver could happend due to couple of reasons:
Case 1
------
Delayed dequeue feature[1] can cause dlserver being stopped during a
pick initiated by dlserver:
__pick_next_task
pick_task_dl -> server_pick_task
pick_task_fair
pick_next_entity (if (sched_delayed))
dequeue_entities
dl_server_stop
server_pick_task goes ahead with update_curr_dl_se without knowing that
dlserver is dequeued and this confuses the logic and may lead to
unintended enqueue while the server is stopped.
Case 2
------
A race condition between a task dequeue on one cpu and same task's enqueue
on this cpu by a remote cpu while the lock is released causing dlserver
double enqueue.
One cpu would be in the schedule() and releasing RQ-lock:
current->state = TASK_INTERRUPTIBLE();
schedule();
deactivate_task()
dl_stop_server();
pick_next_task()
pick_next_task_fair()
sched_balance_newidle()
rq_unlock(this_rq)
at which point another CPU can take our RQ-lock and do:
try_to_wake_up()
ttwu_queue()
rq_lock()
...
activate_task()
dl_server_start() --> first enqueue
wakeup_preempt() := check_preempt_wakeup_fair()
update_curr()
update_curr_task()
if (current->dl_server)
dl_server_update()
enqueue_dl_entity() --> second enqueue
This bug was not apparent as the enqueue in dl_server_start doesn't
usually happen because of the defer logic. But as a side effect of the
first case(dequeue during dlserver pick), dl_throttled and dl_yield will
be set and this causes the time accounting of dlserver to messup and
then leading to a enqueue in dl_server_start.
Have an explicit flag representing the status of dlserver to avoid the
confusion. This is set in dl_server_start and reset in dlserver_stop.
Fixes: 63ba8422f876 ("sched/deadline: Introduce deadline servers")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: "Vineeth Pillai (Google)" <vineeth@bitbyteword.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Marcel Ziswiler <marcel.ziswiler@codethink.co.uk> # ROCK 5B
Link: https://lkml.kernel.org/r/20241213032244.877029-1-vineeth@bitbyteword.org
The rseq uapi requires cooperation between users of the rseq fields to ensure that all libraries and applications using rseq within a process do not interfere with each other. This is especially important for fields which are meant to be read-only from user-space, as documented in uapi/linux/rseq.h: - cpu_id_start, - cpu_id, - node_id, - mm_cid. Storing to those fields from a user-space library prevents any sharing of the rseq ABI with other libraries and applications, as other users are not aware that the content of those fields has been altered by a third-party library. This is unfortunately the current behavior of tcmalloc: it purposefully overlaps part of a cached value with the cpu_id_start upper bits to get notified about preemption, because the kernel clears those upper bits before returning to user-space. This behavior does not conform to the rseq uapi header ABI. This prevents tcmalloc from using rseq when rseq is registered by the GNU C library 2.35+. It requires tcmalloc users to disable glibc rseq registration with a glibc tunable, which is a sad state of affairs. Considering that tcmalloc and the GNU C library are the two first upstream projects using rseq, and that they are already incompatible due to use of this hack, adding kernel-level validation of all read-only fields content is necessary to ensure future users of rseq abide by the rseq ABI requirements. Validate that user-space does not corrupt the read-only fields and conform to the rseq uapi header ABI when the kernel is built with CONFIG_DEBUG_RSEQ=y. This is done by storing a copy of the read-only fields in the task_struct, and validating the prior values present in user-space before updating them. If the values do not match, print a warning on the console (printk_ratelimited()). This is a first step to identify misuses of the rseq ABI by printing a warning on the console. After a giving some time to userspace to correct its use of rseq, the plan is to eventually terminate offending processes with SIGSEGV. This change is expected to produce warnings for the upstream tcmalloc implementation, but tcmalloc developers mentioned they were open to adapt their implementation to kernel-level change. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://github.com/google/tcmalloc/issues/144