Shakeel Butt f689054aac percpu_counter: add percpu_counter_sum_all interface ... The percpu_counter is used for scenarios where performance is more important than the accuracy. For percpu_counter users, who want more accurate information in their slowpath, percpu_counter_sum is provided which traverses all the online CPUs to accumulate the data. The reason it only needs to traverse online CPUs is because percpu_counter does implement CPU offline callback which syncs the local data of the offlined CPU. However there is a small race window between the online CPUs traversal of percpu_counter_sum and the CPU offline callback. The offline callback has to traverse all the percpu_counters on the system to flush the CPU local data which can be a lot. During that time, the CPU which is going offline has already been published as offline to all the readers. So, as the offline callback is running, percpu_counter_sum can be called for one counter which has some state on the CPU going offline. Since percpu_counter_sum only traverses online CPUs, it will skip that specific CPU and the offline callback might not have flushed the state for that specific percpu_counter on that offlined CPU. Normally this is not an issue because percpu_counter users can deal with some inaccuracy for small time window. However a new user i.e. mm_struct on the cleanup path wants to check the exact state of the percpu_counter through check_mm(). For such users, this patch introduces percpu_counter_sum_all() which traverses all possible CPUs and it is used in fork.c:check_mm() to avoid the potential race. This issue is exposed by the later patch "mm: convert mm's rss stats into percpu_counter". Link: https://lkml.kernel.org/r/20221109012011.881058-1-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>		2022-11-30 15:58:40 -08:00
..
bpf	bpf-for-netdev	2022-10-24 10:32:01 -07:00
cgroup	memory: move hotplug memory notifier priority to same file for easy sorting	2022-11-08 17:37:17 -08:00
configs	Kbuild: add Rust support	2022-09-28 09:02:20 +02:00
debug	mm: remove vmacache	2022-09-26 19:46:18 -07:00
dma	- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in	2022-10-10 17:53:04 -07:00
entry	entry: kmsan: introduce kmsan_unpoison_entry_regs()	2022-10-03 14:03:25 -07:00
events	perf/hw_breakpoint: test: Skip the test if dependencies unmet	2022-11-02 12:22:05 +01:00
futex	freezer,sched: Rewrite core freezer logic	2022-09-07 21:53:50 +02:00
gcov	gcov: clang: fix the buffer overflow issue	2022-11-22 18:50:41 -08:00
irq	genirq: Provide generic_handle_domain_irq_safe().	2022-09-19 15:08:38 +02:00
kcsan	treewide: use get_random_bytes() when possible	2022-10-11 17:42:58 -06:00
livepatch	Livepatching changes for 6.1	2022-10-10 11:36:19 -07:00
locking	treewide: use prandom_u32_max() when possible, part 1	2022-10-11 17:42:55 -06:00
module	module: tracking: Keep a record of tainted unloaded modules only	2022-10-10 12:16:19 -07:00
power	PM: hibernate: Allow hybrid sleep to work with s2idle	2022-10-25 14:53:19 +02:00
printk	printk: Mark __printk percpu data ready __ro_after_init	2022-09-29 15:20:52 +02:00
rcu	rcu: Keep synchronize_rcu() from enabling irqs in early boot	2022-10-20 15:34:49 -07:00
sched	sched: Introduce struct balance_callback to avoid CFI mismatches	2022-10-17 16:41:25 +02:00
time	treewide: use prandom_u32_max() when possible, part 1	2022-10-11 17:42:55 -06:00
trace	tracing: kprobe: Fix memory leak in test_gen_kprobe/kretprobe_cmd()	2022-11-04 09:10:03 +09:00
.gitignore	…
Kconfig.freezer	…
Kconfig.hz	…
Kconfig.locks	…
Kconfig.preempt	Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels"	2022-03-31 10:36:55 +02:00
Makefile	kmsan: disable instrumentation of unsupported common kernel code	2022-10-03 14:03:20 -07:00
acct.c	acct: use VMA iterator instead of linked list	2022-09-26 19:46:22 -07:00
async.c	…
audit.c	audit: use time_after to compare time	2022-08-29 19:47:03 -04:00
audit.h	audit: remove selinux_audit_rule_update() declaration	2022-09-07 11:30:15 -04:00
audit_fsnotify.c	audit: fix potential double free on error path from fsnotify_add_inode_mark	2022-08-22 18:50:06 -04:00
audit_tree.c	audit: use fsnotify group lock helpers	2022-04-25 14:37:28 +02:00
audit_watch.c	audit_init_parent(): constify path	2022-09-01 17:39:30 -04:00
auditfilter.c	…
auditsc.c	audit/stable-6.1 PR 20221003	2022-10-04 11:05:43 -07:00
backtracetest.c	…
bounds.c	mm: multi-gen LRU: minimal implementation	2022-09-26 19:46:09 -07:00
capability.c	…
cfi.c	cfi: Switch to -fsanitize=kcfi	2022-09-26 10:13:13 -07:00
compat.c	…
configs.c	…
context_tracking.c	MAINTAINERS: Add Paul as context tracking maintainer	2022-07-05 13:33:00 -07:00
cpu.c	Intel Trust Domain Extensions	2022-05-23 17:51:12 -07:00
cpu_pm.c	context_tracking: Take IRQ eqs entrypoints over RCU	2022-07-05 13:32:59 -07:00
crash_core.c	vmcoreinfo: add kallsyms_num_syms symbol	2022-08-28 14:02:44 -07:00
crash_dump.c	…
cred.c	…
delayacct.c	delayacct: support re-entrance detection of thrashing accounting	2022-09-26 19:46:07 -07:00
dma.c	…
exec_domain.c	…
exit.c	- hfs and hfsplus kmap API modernization from Fabio Francesco	2022-10-12 11:00:22 -07:00
extable.c	context_tracking: Take NMI eqs entrypoints over RCU	2022-07-05 13:32:59 -07:00
fail_function.c	fail_function: fix wrong use of fei_attr_remove()	2022-09-11 21:55:11 -07:00
fork.c	percpu_counter: add percpu_counter_sum_all interface	2022-11-30 15:58:40 -08:00
freezer.c	freezer,sched: Rewrite core freezer logic	2022-09-07 21:53:50 +02:00
gen_kheaders.sh	kbuild: build init/built-in.a just once	2022-09-29 04:40:15 +09:00
groups.c	security: Add LSM hook to setgroups() syscall	2022-07-15 18:21:49 +00:00
hung_task.c	sched: Fix more TASK_state comparisons	2022-09-30 16:50:39 +02:00
iomem.c	…
irq_work.c	irq_work: use kasan_record_aux_stack_noalloc() record callstack	2022-04-15 14:49:55 -07:00
jump_label.c	jump_label: make initial NOP patching the special case	2022-06-24 09:48:55 +02:00
kallsyms.c	kcfi updates for v6.1-rc1	2022-10-03 17:11:07 -07:00
kallsyms_internal.h	kallsyms: move declarations to internal header	2022-07-17 17:31:39 -07:00
kcmp.c	…
kcov.c	kcov: kmsan: unpoison area->list in kcov_remote_area_put()	2022-10-03 14:03:23 -07:00
kexec.c	panic, kexec: make __crash_kexec() NMI safe	2022-09-11 21:55:06 -07:00
kexec_core.c	kexec: replace kmap() with kmap_local_page()	2022-09-11 21:55:08 -07:00
kexec_elf.c	…
kexec_file.c	panic, kexec: make __crash_kexec() NMI safe	2022-09-11 21:55:06 -07:00
kexec_internal.h	panic, kexec: make __crash_kexec() NMI safe	2022-09-11 21:55:06 -07:00
kheaders.c	…
kmod.c	…
kprobes.c	kprobe: reverse kp->flags when arm_kprobe failed	2022-11-04 08:49:31 +09:00
ksysfs.c	kexec: turn all kexec_mutex acquisitions into trylocks	2022-09-11 21:55:06 -07:00
kthread.c	signal: break out of wait loops on kthread_stop()	2022-10-09 16:01:59 -07:00
latencytop.c	latencytop: use the last element of latency_record of system	2022-09-11 21:55:12 -07:00
module_signature.c	…
notifier.c	notifier: Add blocking/atomic_notifier_chain_register_unique_prio()	2022-05-19 19:30:30 +02:00
nsproxy.c	Revert "fs/exec: allow to unshare a time namespace on vfork+exec"	2022-09-13 10:38:43 -07:00
padata.c	…
panic.c	kernel/panic: Drop unblank_screen call	2022-09-01 16:55:35 +02:00
params.c	…
pid.c	gfs2: Add glockfd debugfs file	2022-06-29 13:07:16 +02:00
pid_namespace.c	kernel: pid_namespace: use NULL instead of using plain integer as pointer	2022-04-29 14:38:00 -07:00
profile.c	kernel/profile.c: simplify duplicated code in profile_setup()	2022-09-11 21:55:12 -07:00
ptrace.c	freezer,sched: Rewrite core freezer logic	2022-09-07 21:53:50 +02:00
range.c	…
reboot.c	kernel/reboot: Add SYS_OFF_MODE_RESTART_PREPARE mode	2022-10-04 15:59:36 +02:00
regset.c	…
relay.c	relay: use kvcalloc to alloc page array in relay_alloc_page_array	2022-10-03 14:21:43 -07:00
resource.c	resource: Introduce alloc_free_mem_region()	2022-07-21 17:19:25 -07:00
resource_kunit.c	…
rseq.c	rseq: Kill process when unknown flags are encountered in ABI structures	2022-08-01 15:21:42 +02:00
scftorture.c	scftorture: Fix distribution of short handler delays	2022-04-11 17:07:29 -07:00
scs.c	kasan, vmalloc: only tag normal vmalloc allocations	2022-03-24 19:06:48 -07:00
seccomp.c	seccomp: Add wait_killable semantic to seccomp user notifier	2022-05-03 14:11:58 -07:00
signal.c	Scheduler changes for v6.1:	2022-10-10 09:10:28 -07:00
smp.c	bitmap patches for v6.1-rc1	2022-10-10 12:49:34 -07:00
smpboot.c	smpboot: use atomic_try_cmpxchg in cpu_wait_death and cpu_report_death	2022-09-11 21:55:10 -07:00
smpboot.h	…
softirq.c	context_tracking: Take IRQ eqs entrypoints over RCU	2022-07-05 13:32:59 -07:00
stackleak.c	stackleak: add on/off stack variants	2022-05-08 01:33:09 -07:00
stacktrace.c	…
static_call.c	static_call: Don't make __static_call_return0 static	2022-04-05 09:59:38 +02:00
static_call_inline.c	static_call: Don't make __static_call_return0 static	2022-04-05 09:59:38 +02:00
stop_machine.c	Scheduler changes in this cycle were:	2022-05-24 11:11:13 -07:00
sys.c	Random number generator updates for Linux 6.1-rc1.	2022-10-10 10:41:21 -07:00
sys_ni.c	kernel/sys_ni: add compat entry for fadvise64_64	2022-08-20 15:17:45 -07:00
sysctl-test.c	kernel/sysctl-test: use SYSCTL_{ZERO/ONE_HUNDRED} instead of i_{zero/one_hundred}	2022-09-08 16:56:45 -07:00
sysctl.c	swap: add a limit for readahead page-cluster value	2022-11-08 17:37:22 -08:00
task_work.c	task_work: use try_cmpxchg in task_work_add, task_work_cancel_match and task_work_run	2022-09-11 21:55:10 -07:00
taskstats.c	genetlink: start to validate reserved header bytes	2022-08-29 12:47:15 +01:00
torture.c	…
tracepoint.c	tracepoint: Optimize the critical region of mutex_lock in tracepoint_module_coming()	2022-09-26 13:01:18 -04:00
tsacct.c	taskstats: version 12 with thread group and exe info	2022-04-29 14:38:03 -07:00
ucount.c	ucounts: Split rlimit and ucount values and max values	2022-05-18 18:24:57 -05:00
uid16.c	…
uid16.h	…
umh.c	freezer,sched: Rewrite core freezer logic	2022-09-07 21:53:50 +02:00
up.c	…
user-return-notifier.c	…
user.c	…
user_namespace.c	ucounts: Split rlimit and ucount values and max values	2022-10-09 16:24:05 -07:00
usermode_driver.c	blob_to_mnt(): kern_unmount() is needed to undo kern_mount()	2022-05-19 23:25:47 -04:00
utsname.c	…
utsname_sysctl.c	kernel/utsname_sysctl.c: Fix hostname polling	2022-10-23 12:01:01 -07:00
watch_queue.c	This was a moderately busy cycle for documentation, but nothing all that	2022-08-02 19:24:24 -07:00
watchdog.c	powerpc updates for 6.0	2022-08-06 16:38:17 -07:00
watchdog_hld.c	Revert "printk: add functions to prefer direct printing"	2022-06-23 18:41:40 +02:00
workqueue.c	kcfi updates for v6.1-rc1	2022-10-03 17:11:07 -07:00
workqueue_internal.h	…