Repository files (latest commit first)

Filename	Latest commit message	Latest commit date
Zhang, Jun 1d1f898df6 rcu: Do RCU GP kthread self-wakeup from softirq and interrupt ... The rcu_gp_kthread_wake() function is invoked when it might be necessary to wake the RCU grace-period kthread. Because self-wakeups are normally a useless waste of CPU cycles, if rcu_gp_kthread_wake() is invoked from this kthread, it naturally refuses to do the wakeup. Unfortunately, natural though it might be, this heuristic fails when rcu_gp_kthread_wake() is invoked from an interrupt or softirq handler that interrupted the grace-period kthread just after the final check of the wait-event condition but just before the schedule() call. In this case, a wakeup is required, even though the call to rcu_gp_kthread_wake() is within the RCU grace-period kthread's context. Failing to provide this wakeup can result in grace periods failing to start, which in turn results in out-of-memory conditions. This race window is quite narrow, but it actually did happen during real testing. It would of course need to be fixed even if it was strictly theoretical in nature. This patch does not Cc stable because it does not apply cleanly to earlier kernel versions. Fixes: 48a7639ce8 ("rcu: Make callers awaken grace-period kthread") Reported-by: "He, Bo" <bo.he@intel.com> Co-developed-by: "Zhang, Jun" <jun.zhang@intel.com> Co-developed-by: "He, Bo" <bo.he@intel.com> Co-developed-by: "xiao, jin" <jin.xiao@intel.com> Co-developed-by: Bai, Jie A <jie.a.bai@intel.com> Signed-off: "Zhang, Jun" <jun.zhang@intel.com> Signed-off: "He, Bo" <bo.he@intel.com> Signed-off: "xiao, jin" <jin.xiao@intel.com> Signed-off: Bai, Jie A <jie.a.bai@intel.com> Signed-off-by: "Zhang, Jun" <jun.zhang@intel.com> [ paulmck: Switch from !in_softirq() to "!in_interrupt() && !in_serving_softirq() to avoid redundant wakeups and to also handle the interrupt-handler scenario as well as the softirq-handler scenario that actually occurred in testing. ] Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Link: https://lkml.kernel.org/r/CD6925E8781EFD4D8E11882D20FC406D52A11F61@SHSMSX104.ccr.corp.intel.com		2019-01-25 15:29:59 -08:00
..
bpf	bpf: fix bpffs bitfield pretty print	2019-01-11 10:40:54 +01:00
cgroup	Merge branch 'for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2018-12-29 10:57:20 -08:00
configs	kvm_config: add CONFIG_VIRTIO_MENU	2018-10-24 20:55:56 -04:00
debug	kdb: use bool for binary state indicators	2018-12-30 08:31:52 +00:00
dma	swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit	2019-01-16 09:59:17 -05:00
events	Remove 'type' argument from access_ok() function	2019-01-03 18:57:57 -08:00
gcov
irq	genirq/affinity: Add is_managed to struct irq_affinity_desc	2018-12-19 11:32:08 +01:00
livepatch	livepatch: Replace synchronize_sched() with synchronize_rcu()	2018-12-01 12:38:50 -08:00
locking	kernel/locking/mutex.c: remove caller signal_pending branch predictions	2019-01-04 13:13:48 -08:00
power	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
printk	Remove 'type' argument from access_ok() function	2019-01-03 18:57:57 -08:00
rcu	rcu: Do RCU GP kthread self-wakeup from softirq and interrupt	2019-01-25 15:29:59 -08:00
sched	jump_label: move 'asm goto' support test to Kconfig	2019-01-06 09:46:51 +09:00
time	y2038: more syscalls and cleanups	2018-12-28 12:45:04 -08:00
trace	tracing/kprobes: Fix NULL pointer dereference in trace_kprobe_create()	2019-01-15 11:33:45 -05:00
.gitignore
acct.c
async.c
audit.c	audit: remove duplicated include from audit.c	2018-12-14 12:09:30 -05:00
audit.h	audit: use current whenever possible	2018-11-26 18:41:21 -05:00
audit_fsnotify.c	audit: minimize our use of audit_log_format()	2018-11-26 18:40:00 -05:00
audit_tree.c	audit: minimize our use of audit_log_format()	2018-11-26 18:40:00 -05:00
audit_watch.c	audit: minimize our use of audit_log_format()	2018-11-26 18:40:00 -05:00
auditfilter.c
auditsc.c	audit: use current whenever possible	2018-11-26 18:41:21 -05:00
backtracetest.c
bounds.c	kbuild: fix kernel/bounds.c 'W=1' warning	2018-10-31 08:54:14 -07:00
capability.c
compat.c	make 'user_access_begin()' do 'access_ok()'	2019-01-04 12:56:09 -08:00
configs.c
context_tracking.c
cpu.c	x86/speculation: Rework SMT state change	2018-11-28 11:57:07 +01:00
cpu_pm.c
crash_core.c	kernel/crash_core.c: print timestamp using time64_t	2018-08-22 10:52:47 -07:00
crash_dump.c
cred.c	cred: export get_task_cred().	2018-12-19 13:52:44 -05:00
delayacct.c	delayacct: track delays from thrashing cache pages	2018-10-26 16:26:32 -07:00
dma.c
elfcore.c
exec_domain.c
exit.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2019-01-16 05:13:36 +12:00
extable.c
fail_function.c	kernel/fail_function.c: remove meaningless null pointer check before debugfs_remove_recursive	2018-10-31 08:54:12 -07:00
fork.c	Merge branch 'akpm' (patches from Andrew)	2019-01-08 18:58:29 -08:00
freezer.c	PM / reboot: Eliminate race between reboot and suspend	2018-08-06 12:35:20 +02:00
futex.c	Remove 'type' argument from access_ok() function	2019-01-03 18:57:57 -08:00
groups.c
hung_task.c	kernel/hung_task.c: break RCU locks based on jiffies	2019-01-04 13:13:45 -08:00
iomem.c
irq_work.c
jump_label.c	jump_label: move 'asm goto' support test to Kconfig	2019-01-06 09:46:51 +09:00
kallsyms.c	kallsyms: reduce size a little on 64-bit	2018-09-10 22:54:33 +09:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt	kconfig: warn no new line at end of file	2018-12-15 17:44:35 +09:00
kcov.c	kernel/kcov.c: mark write_comp_data() as notrace	2019-01-04 13:13:47 -08:00
kexec.c	kexec: add call to LSM hook in original kexec_load syscall	2018-07-16 12:31:57 -07:00
kexec_core.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
kexec_file.c	kexec_file: kexec_walk_memblock() only walks a dedicated region at kdump	2018-12-06 14:38:50 +00:00
kexec_internal.h
kmod.c
kprobes.c	Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2018-12-26 14:45:18 -08:00
ksysfs.c
kthread.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2018-08-13 11:25:07 -07:00
latencytop.c
Makefile	kbuild: change filechk to surround the given command with { }	2019-01-06 09:46:51 +09:00
memremap.c	mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm	2018-12-28 12:11:52 -08:00
module-internal.h
module.c	jump_label: move 'asm goto' support test to Kconfig	2019-01-06 09:46:51 +09:00
module_signing.c	modsign: use all trusted keys to verify module signature	2018-11-07 14:41:41 +01:00
notifier.c
nsproxy.c
padata.c	padata: clean an indentation issue, remove extraneous space	2018-11-16 14:11:04 +08:00
panic.c	kernel/sysctl: add panic_print into sysctl	2019-01-04 13:13:47 -08:00
params.c
pid.c	Fix failure path in alloc_pid()	2018-12-28 12:42:30 -08:00
pid_namespace.c	signal: Use group_send_sig_info to kill all processes in a pid namespace	2018-09-16 16:08:25 +02:00
profile.c	mm: remove include/linux/bootmem.h	2018-10-31 08:54:16 -07:00
ptrace.c	Remove 'type' argument from access_ok() function	2019-01-03 18:57:57 -08:00
range.c
reboot.c	kernel/reboot.c: export pm_power_off_prepare	2018-09-11 16:13:24 +01:00
relay.c
resource.c	kernel, resource: check for IORESOURCE_SYSRAM in release_mem_region_adjustable	2018-12-28 12:11:49 -08:00
rseq.c	Remove 'type' argument from access_ok() function	2019-01-03 18:57:57 -08:00
seccomp.c	seccomp: fix UAF in user-trap code	2019-01-15 09:43:12 -08:00
signal.c	Remove 'type' argument from access_ok() function	2019-01-03 18:57:57 -08:00
smp.c	smp,cpumask: introduce on_each_cpu_cond_mask	2018-10-09 16:51:11 +02:00
smpboot.c
smpboot.h
softirq.c	Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2018-10-25 11:43:47 -07:00
stackleak.c	stackleak: Mark stackleak_track_stack() as notrace	2018-12-05 19:31:44 -08:00
stacktrace.c
stop_machine.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2018-08-13 11:25:07 -07:00
sys.c	kernel/sys.c: Clarify that UNAME26 does not generate unique versions anymore	2019-01-14 10:38:03 +12:00
sys_ni.c	y2038: socket: Add compat_sys_recvmmsg_time64	2018-12-18 16:13:04 +01:00
sysctl.c	kernel/sysctl: add panic_print into sysctl	2019-01-04 13:13:47 -08:00
sysctl_binary.c	kernel/sysctl: add panic_print into sysctl	2019-01-04 13:13:47 -08:00
task_work.c
taskstats.c
test_kprobes.c
torture.c	torture: Remove unnecessary "ret" variables	2018-12-01 12:45:35 -08:00
tracepoint.c	tracing: Replace synchronize_sched() and call_rcu_sched()	2018-11-27 09:21:41 -08:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c	umh: add exit routine for UMH process	2019-01-11 18:05:40 -08:00
up.c	smp,cpumask: introduce on_each_cpu_cond_mask	2018-10-09 16:51:11 +02:00
user-return-notifier.c
user.c	userns: use irqsave variant of refcount_dec_and_lock()	2018-08-22 10:52:47 -07:00
user_namespace.c	userns: also map extents in the reverse map to kernel IDs	2018-11-07 23:51:16 -06:00
utsname.c
utsname_sysctl.c	sys: don't hold uts_sem while accessing userspace memory	2018-08-11 02:05:53 -05:00
watchdog.c	watchdog: Mark watchdog touch functions as notrace	2018-08-30 12:56:40 +02:00
watchdog_hld.c	watchdog: Mark watchdog touch functions as notrace	2018-08-30 12:56:40 +02:00
workqueue.c	workqueue: Replace call_rcu_sched() with call_rcu()	2018-11-27 09:21:44 -08:00
workqueue_internal.h