linux/kernel
Quentin Perret f4dddf90d5 sched: Skip priority checks with SCHED_FLAG_KEEP_PARAMS
SCHED_FLAG_KEEP_PARAMS can be passed to sched_setattr to specify that
the call must not touch scheduling parameters (nice or priority). This
is particularly handy for uclamp when used in conjunction with
SCHED_FLAG_KEEP_POLICY as that allows to issue a syscall that only
impacts uclamp values.

However, sched_setattr always checks whether the priorities and nice
values passed in sched_attr are valid first, even if those never get
used down the line. This is useless at best since userspace can
trivially bypass this check to set the uclamp values by specifying low
priorities. However, it is cumbersome to do so as there is no single
expression of this that skips both RT and CFS checks at once. As such,
userspace needs to query the task policy first with e.g. sched_getattr
and then set sched_attr.sched_priority accordingly. This is racy and
slower than a single call.

As the priority and nice checks are useless when SCHED_FLAG_KEEP_PARAMS
is specified, simply inherit them in this case to match the policy
inheritance of SCHED_FLAG_KEEP_POLICY.

Reported-by: Wei Wang <wvw@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Qais Yousef <qais.yousef@arm.com>
Link: https://lore.kernel.org/r/20210805102154.590709-3-qperret@google.com
2021-08-06 14:25:25 +02:00
..
bpf bpf, lockdown, audit: Fix buggy SELinux lockdown permission checks 2021-06-02 21:59:22 +02:00
cgroup sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
configs drivers/char: remove /dev/kmem for good 2021-05-07 00:26:34 -07:00
debug sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
dma Merge branch 'stable/for-linus-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb 2021-05-04 10:58:49 -07:00
entry tick/nohz: Only check for RCU deferred wakeup on user/guest entry when needed 2021-05-31 10:14:49 +02:00
events sched,perf,kvm: Fix preemption condition 2021-06-18 11:43:07 +02:00
gcov gcov: clang: drop support for clang-10 and older 2021-05-07 00:26:32 -07:00
irq gpio updates for v5.13 2021-05-05 12:39:29 -07:00
kcsan sched: Introduce task_is_running() 2021-06-18 11:43:07 +02:00
livepatch Livepatching changes for 5.13 2021-04-27 18:14:38 -07:00
locking sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
power PM: sleep: fix typos in comments 2021-04-08 19:37:21 +02:00
printk kernel/printk.c: Fixed mundane typos 2021-03-30 15:34:17 +02:00
rcu sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
sched sched: Skip priority checks with SCHED_FLAG_KEEP_PARAMS 2021-08-06 14:25:25 +02:00
time sched,timer: Use __set_current_state() 2021-06-18 11:43:08 +02:00
trace tracing: Correct the length check which causes memory corruption 2021-06-08 16:44:00 -04:00
.gitignore .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
acct.c kernel/acct.c: use #elif instead of #end and #elif 2020-12-15 22:46:15 -08:00
async.c kernel/async.c: remove async_unregister_domain() 2021-05-07 00:26:33 -07:00
audit_fsnotify.c audit_alloc_mark(): don't open-code ERR_CAST() 2021-02-23 10:25:27 -05:00
audit_tree.c fsnotify: generalize handle_inode_event() 2020-12-03 14:58:35 +01:00
audit_watch.c fsnotify: generalize handle_inode_event() 2020-12-03 14:58:35 +01:00
audit.c lsm: separate security_task_getsecid() into subjective and objective variants 2021-03-22 15:23:32 -04:00
audit.h audit: avoid -Wempty-body warning 2021-03-24 12:11:48 -04:00
auditfilter.c lsm: separate security_task_getsecid() into subjective and objective variants 2021-03-22 15:23:32 -04:00
auditsc.c audit/stable-5.13 PR 20210426 2021-04-27 13:50:58 -07:00
backtracetest.c
bounds.c
capability.c capability: handle idmapped mounts 2021-01-24 14:27:16 +01:00
cfi.c add support for Clang CFI 2021-04-08 16:04:20 -07:00
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c cpumask/hotplug: Fix cpu_dying() state tracking 2021-04-21 13:55:43 +02:00
crash_core.c kdump: append uts_namespace.name offset to VMCOREINFO 2020-12-15 22:46:18 -08:00
crash_dump.c
cred.c kernel/cred.c: make init_groups static 2021-05-06 19:24:11 -07:00
delayacct.c delayacct: Add sysctl to enable at runtime 2021-05-12 11:43:25 +02:00
dma.c
exec_domain.c
exit.c do_wait: make PIDTYPE_PID case O(1) instead of O(n) 2021-05-06 19:24:13 -07:00
extable.c
fail_function.c fault-injection: handle EI_ETYPE_TRUE 2020-12-15 22:46:19 -08:00
fork.c sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
freezer.c sched: Add get_current_state() 2021-06-18 11:43:08 +02:00
futex.c futex: Make syscall entry points less convoluted 2021-05-06 20:19:04 +02:00
gen_kheaders.sh kbuild: redo fake deps at include/config/*.h 2021-04-25 05:26:10 +09:00
groups.c groups: simplify struct group_info allocation 2021-02-26 09:41:03 -08:00
hung_task.c sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
iomem.c
irq_work.c irq_work: Make irq_work_queue() NMI-safe again 2021-06-10 10:00:08 +02:00
jump_label.c static_call: Fix static_call_update() sanity check 2021-03-19 13:16:44 +01:00
kallsyms.c kallsyms: strip ThinLTO hashes from static functions 2021-04-08 16:04:21 -07:00
kcmp.c Merge branch 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2020-12-15 19:36:48 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt sched: Add CONFIG_SCHED_CORE help text 2021-06-01 16:00:10 +02:00
kcov.c kernel: make kcov_common_handle consider the current context 2020-11-02 18:00:20 -08:00
kexec_core.c kexec: dump kmessage before machine_kexec 2021-05-07 00:26:32 -07:00
kexec_elf.c
kexec_file.c kernel: kexec_file: fix error return code of kexec_calculate_store_digests() 2021-05-07 00:26:32 -07:00
kexec_internal.h kexec: move machine_kexec_post_load() to public interface 2021-02-22 12:33:26 +00:00
kexec.c
kheaders.c
kmod.c modules: add CONFIG_MODPROBE_PATH 2021-05-07 00:26:33 -07:00
kprobes.c kprobes: Fix to delay the kprobes jump optimization 2021-02-19 14:57:12 -05:00
ksysfs.c
kthread.c sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
latencytop.c
Makefile kbuild: update config_data.gz only when the content of .config is changed 2021-05-02 00:43:35 +09:00
module_signature.c module: harden ELF info handling 2021-01-19 10:24:45 +01:00
module_signing.c module: harden ELF info handling 2021-01-19 10:24:45 +01:00
module-internal.h
module.c module: check for exit sections in layout_sections() instead of module_init_section() 2021-05-17 09:48:24 +02:00
notifier.c
nsproxy.c fixes-v5.11 2020-12-14 16:40:27 -08:00
padata.c
panic.c panic: don't dump stack twice on warn 2020-11-14 11:26:04 -08:00
params.c Modules updates for v5.11 2020-12-17 13:01:31 -08:00
pid_namespace.c fixes-v5.11 2020-12-14 16:40:27 -08:00
pid.c Merge branch 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2020-12-15 19:36:48 -08:00
profile.c kernel: Initialize cpumask before parsing 2021-04-10 13:35:54 +02:00
ptrace.c sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
range.c kernel.h: split out min()/max() et al. helpers 2020-10-16 11:11:19 -07:00
reboot.c Revert "PM: ACPI: reboot: Use S5 for reboot" 2021-03-18 16:58:02 +01:00
regset.c
relay.c relay: allow the use of const callback structs 2020-12-15 22:46:18 -08:00
resource_kunit.c resource: provide meaningful MODULE_LICENSE() in test suite 2020-11-25 18:52:35 +01:00
resource.c kernel/resource: fix return code check in __request_free_mem_region 2021-05-14 19:41:32 -07:00
rseq.c rseq: Optimise rseq_get_rseq_cs() and clear_rseq_cs() 2021-04-14 18:04:09 +02:00
scftorture.c scftorture: Add debug output for wrong-CPU warning 2021-01-04 13:53:41 -08:00
scs.c scs: switch to vmapped shadow stacks 2020-12-01 10:30:28 +00:00
seccomp.c seccomp: Refactor notification handler to prepare for new semantics 2021-05-29 11:13:27 -07:00
signal.c sched: Introduce task_is_running() 2021-06-18 11:43:07 +02:00
smp.c smp: Fix smp_call_function_single_async prototype 2021-05-06 15:33:49 +02:00
smpboot.c sched/core: Initialize the idle task with preemption disabled 2021-05-12 13:01:45 +02:00
smpboot.h
softirq.c sched: Introduce task_is_running() 2021-06-18 11:43:07 +02:00
stackleak.c
stacktrace.c
static_call.c static_call: Fix unused variable warn w/o MODULE 2021-04-09 13:22:12 +02:00
stop_machine.c stop_machine: Add caller debug info to queue_stop_cpus_work 2021-03-23 16:01:58 +01:00
sys_ni.c Add Landlock, a new LSM from Mickaël Salaün <mic@linux.microsoft.com> 2021-05-01 18:50:44 -07:00
sys.c sched: prctl() core-scheduling interface 2021-05-12 11:43:31 +02:00
sysctl-test.c
sysctl.c Merge branch 'sched/urgent' into sched/core, to pick up fixes 2021-06-03 19:00:49 +02:00
task_work.c kasan: record task_work_add() call stack 2021-04-30 11:20:42 -07:00
taskstats.c treewide: rename nla_strlcpy to nla_strscpy. 2020-11-16 08:08:54 -08:00
test_kprobes.c
torture.c torture: Replace torture_init_begin string with %s 2021-03-08 14:22:28 -08:00
tracepoint.c tracepoints: Code clean up 2021-02-09 12:27:29 -05:00
tsacct.c
ucount.c fanotify: configurable limits via sysfs 2021-03-16 16:49:31 +01:00
uid16.c
uid16.h
umh.c kernel/umh.c: fix some spelling mistakes 2021-05-07 00:26:34 -07:00
up.c A set of locking related fixes and updates: 2021-05-09 13:07:03 -07:00
user_namespace.c kernel/user_namespace.c: fix typos 2021-05-07 00:26:34 -07:00
user-return-notifier.c
user.c
usermode_driver.c bpf: Fix umd memory leak in copy_process() 2021-03-19 22:23:19 +01:00
utsname_sysctl.c
utsname.c
watch_queue.c watch_queue: rectify kernel-doc for init_watch() 2021-01-26 11:16:34 +00:00
watchdog_hld.c
watchdog.c watchdog: reliable handling of timestamps 2021-05-22 15:09:07 -10:00
workqueue_internal.h
workqueue.c wq: handle VM suspension in stall detection 2021-05-20 12:58:30 -04:00