Ben Hutchings c591fcb123 futex: Futex_unlock_pi() determinism ...

From: Peter Zijlstra <peterz@infradead.org>

commit bebe5b5143 upstream.

The problem with returning -EAGAIN when the waiter state mismatches is that
it becomes very hard to proof a bounded execution time on the
operation. And seeing that this is a RT operation, this is somewhat
important.

While in practise; given the previous patch; it will be very unlikely to
ever really take more than one or two rounds, proving so becomes rather
hard.

However, now that modifying wait_list is done while holding both hb->lock
and wait_lock, the scenario can be avoided entirely by acquiring wait_lock
while still holding hb-lock. Doing a hand-over, without leaving a hole.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: juri.lelli@arm.com
Cc: bigeasy@linutronix.de
Cc: xlpang@redhat.com
Cc: rostedt@goodmis.org
Cc: mathieu.desnoyers@efficios.com
Cc: jdesfossez@efficios.com
Cc: dvhart@infradead.org
Cc: bristot@redhat.com
Link: http://lkml.kernel.org/r/20170322104152.112378812@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2023-05-16 10:39:23 +09:00

..

bpf

bpf: Check for integer overflow when using roundup_pow_of_two()

2023-05-16 10:35:58 +09:00

configs

ANDROID: add script to fetch android kernel config fragments

2017-10-03 17:19:26 +00:00

debug

kdb: Make memory allocations more robust

2023-05-16 10:36:43 +09:00

events

perf/core: Fix race in the perf_mmap_close() function

2023-05-16 09:48:10 +09:00

gcov

gcov: add support for GCC 10.1

2023-05-16 09:13:10 +09:00

irq

genirq: Let GENERIC_IRQ_IPI select IRQ_DOMAIN_HIERARCHY

2023-05-16 09:46:54 +09:00

livepatch

livepatch/module: make TAINT_LIVEPATCH module-specific

2016-08-26 14:42:08 +02:00

locking

rtmutex: Remove unused argument from rt_mutex_proxy_unlock()

2023-05-16 10:33:53 +09:00

power

PM: hibernate: remove the bogus call to get_gendisk() in software_resume()

2023-05-16 09:39:46 +09:00

printk

printk: handle blank console arguments passed in.

2023-05-16 09:16:27 +09:00

rcu

rcuperf: Fix cleanup path for invalid perf_type strings

2023-05-15 13:36:07 +09:00

sched

sched/fair: handle case of task_h_load() returning 0

2023-05-16 08:31:08 +09:00

time

random32: make prandom_u32() output unpredictable

2023-05-16 09:47:50 +09:00

trace

tracing: Check length before giving out the filter buffer

2023-05-16 10:35:52 +09:00

.gitignore

certs: add .gitignore to stop git nagging about x509_certificate_list

2015-10-21 15:18:35 +01:00

acct.c

kernel/acct.c: fix the acct->needcheck check in check_free_space()

2018-01-10 09:29:51 +01:00

async.c

kernel/async.c: revert "async: simplify lowest_in_progress()"

2018-02-17 13:21:18 +01:00

audit_fsnotify.c

wrappers for ->i_mutex access

2016-01-22 18:04:28 -05:00

audit_tree.c

audit: cleanup prune_tree_thread

2016-04-04 09:46:47 -04:00

audit_watch.c

audit: CONFIG_CHANGE don't log internal bookkeeping as an event

2023-05-16 09:15:30 +09:00

audit.c

audit: check the length of userspace generated audit records

2023-05-15 17:23:39 +09:00

audit.h

Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit

2016-07-29 17:54:17 -07:00

auditfilter.c

audit: fix error handling in audit_data_to_entry()

2023-05-15 17:01:41 +09:00

auditsc.c

audit: print empty EXECVE args

2023-05-15 15:18:40 +09:00

backtracetest.c

…

bounds.c

kbuild: fix kernel/bounds.c 'W=1' warning

2023-05-15 09:22:43 +09:00

capability.c

ptrace: Capture the ptracer's creds not PT_PTRACE_CAP

2017-01-06 10:40:13 +01:00

cfi.c

cfi: print target address on failure

2018-05-01 16:49:34 +00:00

cgroup_freezer.c

cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends

2015-12-03 10:24:08 -05:00

cgroup_pids.c

cgroup: pids: use atomic64_t for pids->limit

2023-05-15 16:16:25 +09:00

cgroup.c

cgroup: add missing skcd->no_refcnt check in cgroup_sk_clone()

2023-05-16 08:45:33 +09:00

compat.c

19af5c5 dtv_demod: add AGC control for board t309 [1/1]

2019-05-06 21:14:10 +08:00

configs.c

…

context_tracking.c

context_tracking: Switch to new static_branch API

2015-11-24 09:56:43 +01:00

cpu_pm.c

kernel/cpu_pm: Fix uninitted local in cpu_pm

2023-05-15 17:34:36 +09:00

cpu.c

kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling

2023-05-16 09:56:17 +09:00

cpuset.c

Merge 4.9.55 into android-4.9

2017-10-12 22:31:24 +02:00

crash_dump.c

…

cred.c

memcg: account security cred as well to kmemcg

2023-05-15 16:30:24 +09:00

delayacct.c

kmemcg: account certain kmem allocations to memcg

2016-01-14 16:00:49 -08:00

dma.c

…

exec_domain.c

Remove rest of exec domains.

2015-04-12 21:03:31 +02:00

exit.c

futex: Mark the begin of futex exit explicitly

2023-05-16 10:33:14 +09:00

extable.c

kernel/extable.c: mark core_kernel_text notrace

2017-07-21 07:42:21 +02:00

fork.c

futex: Split futex_mm_release() for exit/exec

2023-05-16 10:33:12 +09:00

freezer.c

freezer, oom: check TIF_MEMDIE on the correct task

2016-07-28 16:07:41 -07:00

futex.c

futex: Futex_unlock_pi() determinism

2023-05-16 10:39:23 +09:00

groups.c

kernel: make groups_sort calling a responsibility group_info allocators

2018-01-10 09:29:52 +01:00

hung_task.c

kernel: hung_task.c: disable on suspend

2023-05-15 12:23:14 +09:00

irq_work.c

treewide: Remove old email address

2015-11-23 09:44:58 +01:00

jump_label.c

jump_label: Invoke jump_label_test() via early_initcall()

2017-12-14 09:28:24 +01:00

kallsyms.c

rodata: optimize memory usage of rodata section [4/5]

2023-04-21 13:52:34 +09:00

kcmp.c

ptrace: use fsuid, fsgid, effective creds for fs access checks

2016-01-20 17:09:18 -08:00

Kconfig.freezer

…

Kconfig.hz

…

Kconfig.locks

locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS

2015-05-12 09:46:00 +02:00

Kconfig.preempt

…

kcov.c

kcov: ensure irq code sees a valid area

2023-05-12 16:39:07 +09:00

kexec_core.c

objtool, x86: Add several functions and files to the objtool whitelist

2018-06-05 10:28:57 +02:00

kexec_file.c

kexec: fix double-free when failing to relocate the purgatory

2016-09-01 17:52:01 -07:00

kexec_internal.h

kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILE

2016-01-20 17:09:18 -08:00

kexec.c

kexec: allow architectures to override boot mapping

2016-08-02 19:35:27 -04:00

kmod.c

usermodehelper: reset umask to default before executing user process

2023-05-16 09:24:03 +09:00

kprobes.c

kretprobe: Avoid re-registration of the same kretprobe earlier

2023-05-16 10:34:15 +09:00

ksysfs.c

kexec: add a kexec_crash_loaded() function

2016-08-02 19:35:30 -04:00

kthread.c

kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled

2023-05-16 09:46:04 +09:00

latencytop.c

sched/debug: Make schedstats a runtime tunable that is disabled by default

2016-02-09 11:54:23 +01:00

Makefile

elfcore: fix building with clang

2023-05-16 10:34:10 +09:00

membarrier.c

Fix: Disable sys_membarrier when nohz_full is enabled

2017-03-12 06:41:45 +01:00

memremap.c

mm, devm_memremap_pages: kill mapping "System RAM" support

2023-05-15 10:54:41 +09:00

module_signing.c

KEYS: Move the point of trust determination to __key_link()

2016-04-11 22:43:43 +01:00

module-internal.h

…

module.c

module: Ignore _GLOBAL_OFFSET_TABLE_ when warning for undefined symbols

2023-05-16 10:38:49 +09:00

notifier.c

x86/mm: split vmalloc_sync_all()

2023-05-15 17:11:06 +09:00

nsproxy.c

cgroup: introduce cgroup namespaces

2016-02-16 13:04:58 -05:00

padata.c

padata: purge get_cpu and reorder_via_wq from padata_do_serial

2023-05-15 17:28:50 +09:00

panic.c

panic: ensure preemption is disabled during panic()

2023-05-15 14:48:19 +09:00

params.c

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2015-11-09 15:53:39 -08:00

pid_namespace.c

signal/pid_namespace: Fix reboot_pid_ns to use send_sig not force_sig

2023-05-15 13:59:49 +09:00

pid.c

UPSTREAM: locking/atomic, kref: Add KREF_INIT()

2023-05-16 10:25:44 +09:00

profile.c

profile: Convert to hotplug state machine

2016-07-15 10:41:42 +02:00

ptrace.c

ptrace: Fix ->ptracer_cred handling for PTRACE_TRACEME

2023-05-15 13:57:11 +09:00

range.c

…

reboot.c

reboot: fix overflow parsing reboot cpu number

2023-05-16 09:48:13 +09:00

relay.c

kernel/relay.c: fix memleak on destroy relay channel

2023-05-16 08:54:40 +09:00

resource.c

resource: fix integer overflow at reallocation

2018-04-24 09:34:09 +02:00

seccomp.c

seccomp: Add missing return in non-void function

2023-05-16 10:38:38 +09:00

signal.c

signal: Extend exec_id to 64bits

2023-05-15 17:14:27 +09:00

smp.c

cpu/hotplug: Fix SMT supported evaluation

2023-05-12 16:55:46 +09:00

smpboot.c

kthread/smpboot: do not park in kthread_create_on_cpu()

2016-10-11 15:06:33 -07:00

smpboot.h

cpu/hotplug: Create hotplug threads

2016-03-01 20:36:56 +01:00

softirq.c

Mark HI and TASKLET softirq synchronous

2023-05-12 16:46:40 +09:00

stacktrace.c

stacktrace, lockdep: Fix address, newline ugliness

2017-02-14 15:25:42 -08:00

stop_machine.c

stop_machine: Use raw spinlocks

2023-05-12 16:43:35 +09:00

sys_ni.c

x86/pkeys: Fix pkeys build breakage for some non-x86 arches

2016-09-13 14:41:36 +02:00

sys.c

kernel/sys.c: avoid copying possible padding bytes in copy_to_user

2023-05-16 09:15:12 +09:00

sysctl_binary.c

kernel/sysctl_binary.c: use generic UUID library

2016-05-20 17:58:30 -07:00

sysctl.c

sched/rt: Show the 'sched_rr_timeslice' SCHED_RR timeslice tuning knob in milliseconds

2023-05-16 08:29:07 +09:00

task_work.c

task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works

2016-08-02 19:35:02 -04:00

taskstats.c

taskstats: fix data-race

2023-05-15 16:30:15 +09:00

test_kprobes.c

…

torture.c

torture: Convert torture_shutdown() to hrtimer

2016-08-22 10:01:49 -07:00

tracepoint.c

tracepoint: Do not fail unregistering a probe due to memory failure

2023-05-16 10:37:50 +09:00

tsacct.c

time, acct: Drop irq save & restore from __acct_update_integrals()

2016-02-29 09:53:09 +01:00

ucount.c

kernel/ucount.c: mark user_header with kmemleak_ignore()

2017-06-17 06:41:51 +02:00

uid16.c

kernel: make groups_sort calling a responsibility group_info allocators

2018-01-10 09:29:52 +01:00

up.c

smp: Add function to execute a function synchronously on a CPU

2016-09-05 13:52:39 +02:00

user_namespace.c

userns: move user access out of the mutex

2023-05-12 17:24:22 +09:00

user-return-notifier.c

…

user.c

ANDROID: proc: Add /proc/uid directory

2018-04-03 11:15:30 -07:00

utsname_sysctl.c

sys: don't hold uts_sem while accessing userspace memory

2023-05-12 17:24:20 +09:00

utsname.c

Merge branch 'nsfs-ioctls' into HEAD

2016-09-22 20:00:36 -05:00

watchdog_hld.c

debug: hard lockup detect

2018-05-09 19:39:28 -07:00

watchdog.c

debug: hard lockup detect

2018-05-09 19:39:28 -07:00

workqueue_internal.h

workqueue: Fix NULL pointer dereference

2017-11-15 15:53:17 +01:00

workqueue.c

workqueue: Kick a worker based on the actual activation of delayed works

2023-05-16 10:24:49 +09:00