Davidlohr Bueso 7f8ca0edfe kernel/sys.c: only take tasklist_lock for get/setpriority(PRIO_PGRP) ... PRIO_PGRP needs the tasklist_lock mainly to serialize vs setpgid(2), to protect against any concurrent change_pid(PIDTYPE_PGID) that can move the task from one hlist to another while iterating. However, the remaining can only rely only on RCU: PRIO_PROCESS only does the task lookup and never iterates over tasklist and we already have an rcu-aware stable pointer. PRIO_USER is already racy vs setuid(2) so with creds being rcu protected, we can end up seeing stale data. When removing the tasklist_lock there can be a race with (i) fork but this is benign as the child's nice is inherited and the new task is not observable by the user yet either, hence the return semantics do not differ. And (ii) a race with exit, which is a small window and can cause us to miss a task which was removed from the list and it had the highest nice. Similarly change the buggy do_each_thread/while_each_thread combo in PRIO_USER for the rcu-safe for_each_process_thread flavor, which doesn't make use of next_thread/p->thread_group. [akpm@linux-foundation.org: coding style fixes] Link: https://lkml.kernel.org/r/20211210182250.43734-1-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2022-01-20 08:52:53 +02:00
..
bpf	bpf: Make 32->64 bounds propagation slightly more robust	2021-12-16 19:45:56 +01:00
cgroup	cgroup: Use open-time cgroup namespace for process migration perm checks	2022-01-06 11:02:29 -10:00
configs	drivers/char: remove /dev/kmem for good	2021-05-07 00:26:34 -07:00
debug	kdb: Adopt scheduler's task classification	2021-11-03 17:21:37 +00:00
dma	dma-mapping updates for Linux 5.16	2021-11-09 10:56:41 -08:00
entry	signal: Replace force_fatal_sig with force_exit_sig when in doubt	2021-11-19 09:15:58 -06:00
events	perf: Ignore sigtrap for tracepoints destined for other tasks	2021-11-23 09:45:37 +01:00
futex	futex: Fix PREEMPT_RT build	2021-10-19 17:27:05 +02:00
gcov	Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR	2021-06-22 11:07:18 -07:00
irq	PCI/MSI: Move non-mask check back into low level accessors	2021-11-11 09:50:30 +01:00
kcsan	kcsan: selftest: Cleanup and add missing __init	2021-09-13 16:41:20 -07:00
livepatch	Tracing updates for 5.16:	2021-11-01 20:05:19 -07:00
locking	locking/rtmutex: Fix incorrect condition in rtmutex_spin_on_owner()	2021-12-18 10:55:51 +01:00
power	PM: hibernate: Fix snapshot partial write lengths	2021-11-24 13:50:18 +01:00
printk	printk fixup for 5.16	2021-11-18 10:50:45 -08:00
rcu	RCU pull request for v5.16	2021-11-01 20:25:38 -07:00
sched	wait: add wake_up_pollfree()	2021-12-09 10:49:56 -08:00
time	timekeeping: Really make sure wall_to_monotonic isn't positive	2021-12-17 23:06:22 +01:00
trace	tracing: Tag trace_percpu_buffer as a percpu pointer	2022-01-05 18:53:49 -05:00
.gitignore	.gitignore: prefix local generated files with a slash	2021-05-02 00:43:35 +09:00
acct.c	kernel: remove spurious blkdev.h includes	2021-10-18 06:17:01 -06:00
async.c	kernel/async.c: remove async_unregister_domain()	2021-05-07 00:26:33 -07:00
audit_fsnotify.c	fsnotify: clarify contract for create event hooks	2021-10-27 12:32:34 +02:00
audit_tree.c	audit/stable-5.16 PR 20211101	2021-11-01 21:17:39 -07:00
audit_watch.c	\n	2021-11-06 16:43:20 -07:00
audit.c	audit: improve robustness of the audit queue handling	2021-12-15 13:16:39 -05:00
audit.h	audit/stable-5.16 PR 20211101	2021-11-01 21:17:39 -07:00
auditfilter.c	audit: add filtering for io_uring records	2021-09-19 22:34:38 -04:00
auditsc.c	audit/stable-5.16 PR 20211101	2021-11-01 21:17:39 -07:00
backtracetest.c
bounds.c
capability.c	capability: handle idmapped mounts	2021-01-24 14:27:16 +01:00
cfi.c	cfi: Use rcu_read_{un}lock_sched_notrace	2021-08-11 13:11:12 -07:00
compat.c	arch: remove compat_alloc_user_space	2021-09-08 15:32:35 -07:00
configs.c
context_tracking.c
cpu_pm.c	PM: cpu: Make notifier chain use a raw_spinlock_t	2021-08-16 18:55:32 +02:00
cpu.c	sched/scs: Reset task stack state in bringup_cpu()	2021-11-24 12:20:27 +01:00
crash_core.c	kernel/crash_core: suppress unknown crashkernel parameter warning	2021-12-25 12:20:55 -08:00
crash_dump.c
cred.c	ucounts: In set_cred_ucounts assume new->ucounts is non-NULL	2021-10-20 10:45:34 -05:00
delayacct.c	delayacct: Add sysctl to enable at runtime	2021-05-12 11:43:25 +02:00
dma.c
exec_domain.c
exit.c	Merge branch 'per_signal_struct_coredumps-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2021-11-03 12:15:29 -07:00
extable.c	extable: use is_kernel_text() helper	2021-11-09 10:02:51 -08:00
fail_function.c
fork.c	A single fix for POSIX CPU timers to address a problem where POSIX CPU	2021-11-14 10:43:38 -08:00
freezer.c	sched: Add get_current_state()	2021-06-18 11:43:08 +02:00
gen_kheaders.sh	kbuild: clean up ${quiet} checks in shell scripts	2021-05-27 04:01:50 +09:00
groups.c	groups: simplify struct group_info allocation	2021-02-26 09:41:03 -08:00
hung_task.c	Merge branch 'akpm' (patches from Andrew)	2021-07-02 12:08:10 -07:00
iomem.c
irq_work.c	irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT	2021-10-15 11:25:18 +02:00
jump_label.c	jump_label: Fix jump_label_text_reserved() vs __init	2021-07-05 10:46:20 +02:00
kallsyms.c	kallsyms: strip LTO suffixes from static functions	2021-10-04 10:58:25 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks	locking/rwlock: Provide RT variant	2021-08-17 17:50:51 +02:00
Kconfig.preempt	preempt: Restore preemption model selection configs	2021-11-11 13:09:33 +01:00
kcov.c	kcov: replace local_irq_save() with a local_lock_t	2021-11-09 10:02:52 -08:00
kexec_core.c	Merge branch 'rework/printk_safe-removal' into for-linus	2021-08-30 16:36:10 +02:00
kexec_elf.c
kexec_file.c	memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED	2021-11-06 13:30:42 -07:00
kexec_internal.h	kexec: move machine_kexec_post_load() to public interface	2021-02-22 12:33:26 +00:00
kexec.c	kexec: avoid compat_alloc_user_space	2021-09-08 15:32:34 -07:00
kheaders.c
kmod.c	modules: add CONFIG_MODPROBE_PATH	2021-05-07 00:26:33 -07:00
kprobes.c	kprobes: Limit max data_size of the kretprobe instances	2021-12-01 21:04:34 -05:00
ksysfs.c
kthread.c	kthread: dynamically allocate memory to store kthread's full name	2022-01-20 08:52:53 +02:00
latencytop.c
Makefile	Tracing updates for 5.16:	2021-11-01 20:05:19 -07:00
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: change to print useful messages from elf_validity_check()	2021-11-05 15:13:10 -07:00
notifier.c	notifier: Remove atomic_notifier_call_chain_robust()	2021-08-16 18:55:32 +02:00
nsproxy.c	memcg: enable accounting for new namesapces and struct nsproxy	2021-09-03 09:58:12 -07:00
padata.c	padata: Remove repeated verbose license text	2021-08-27 16:30:18 +08:00
panic.c	Merge branch 'rework/printk_safe-removal' into for-linus	2021-08-30 16:36:10 +02:00
params.c	params: lift param_set_uint_minmax to common code	2021-08-16 14:42:22 +02:00
pid_namespace.c	memcg: enable accounting for new namesapces and struct nsproxy	2021-09-03 09:58:12 -07:00
pid.c	pid: add pidfd_get_task() helper	2021-10-14 13:29:18 +02:00
profile.c	profiling: fix shift-out-of-bounds bugs	2021-09-08 11:50:26 -07:00
ptrace.c	sched: Change task_struct::state	2021-06-18 11:43:09 +02:00
range.c
reboot.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2021-11-12 11:53:16 -08:00
regset.c
relay.c
resource_kunit.c
resource.c	kernel/resource: disallow access to exclusive system RAM regions	2021-11-09 10:02:52 -08:00
rseq.c	KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest	2021-09-22 10:24:01 -04:00
scftorture.c	scftorture: Warn on individual scf_torture_init() error conditions	2021-09-16 10:27:48 -07:00
scs.c	scs: Release kasan vmalloc poison in scs_free process	2021-09-30 09:37:27 +01:00
seccomp.c	Merge branch 'exit-cleanups-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2021-09-01 14:52:05 -07:00
signal.c	signal: Skip the altstack update when not needed	2021-12-14 13:08:36 -08:00
smp.c	sched: Improve wake_up_all_idle_cpus() take #2	2021-10-22 15:32:46 +02:00
smpboot.c	smpboot: Replace deprecated CPU-hotplug functions.	2021-08-10 14:57:42 +02:00
smpboot.h
softirq.c	timers/nohz: Last resort update jiffies on nohz_full IRQ entry	2021-12-02 15:07:22 +01:00
stackleak.c
stacktrace.c	stacktrace: move filter_irq_stacks() to kernel/stacktrace.c	2021-11-06 13:30:43 -07:00
static_call.c	static_call: Fix static_call_text_reserved() vs __init	2021-07-05 10:46:33 +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	futex: Implement sys_futex_waitv()	2021-10-07 13:51:11 +02:00
sys.c	kernel/sys.c: only take tasklist_lock for get/setpriority(PRIO_PGRP)	2022-01-20 08:52:53 +02:00
sysctl-test.c	kernel/sysctl-test: Remove some casts which are no-longer required	2021-06-23 16:41:24 -06:00
sysctl.c	Merge branch 'akpm' (patches from Andrew)	2021-09-03 10:08:28 -07:00
task_work.c	kasan: record task_work_add() call stack	2021-04-30 11:20:42 -07:00
taskstats.c
torture.c	torture: Replace deprecated CPU-hotplug functions.	2021-08-10 10:48:07 -07:00
tracepoint.c	tracepoint: Fix kerneldoc comments	2021-08-16 11:39:51 -04:00
tsacct.c	mm/mmap.c: fix a data race of mm->total_vm	2021-11-06 13:30:35 -07:00
ucount.c	ucounts: Fix rlimit max values check	2021-12-09 15:37:18 -06:00
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	memcg: enable accounting for new namesapces and struct nsproxy	2021-09-03 09:58:12 -07:00
user-return-notifier.c
user.c	fs/epoll: use a per-cpu counter for user's watches count	2021-09-08 11:50:27 -07:00
usermode_driver.c	Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2021-07-03 11:41:14 -07:00
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	kernel: watchdog: modify the explanation related to watchdog thread	2021-06-29 10:53:46 -07:00
workqueue_internal.h	workqueue: Assign a color to barrier work items	2021-08-17 07:49:10 -10:00
workqueue.c	Merge branch 'akpm' (patches from Andrew)	2021-11-06 14:08:17 -07:00