Daniel Bristot de Oliveira 088e9d253d rcu: sysctl: Panic on RCU Stall ... It is not always easy to determine the cause of an RCU stall just by analysing the RCU stall messages, mainly when the problem is caused by the indirect starvation of rcu threads. For example, when preempt_rcu is not awakened due to the starvation of a timer softirq. We have been hard coding panic() in the RCU stall functions for some time while testing the kernel-rt. But this is not possible in some scenarios, like when supporting customers. This patch implements the sysctl kernel.panic_on_rcu_stall. If set to 1, the system will panic() when an RCU stall takes place, enabling the capture of a vmcore. The vmcore provides a way to analyze all kernel/tasks states, helping out to point to the culprit and the solution for the stall. The kernel.panic_on_rcu_stall sysctl is disabled by default. Changes from v1: - Fixed a typo in the git log - The if(sysctl_panic_on_rcu_stall) panic() is in a static function - Fixed the CONFIG_TINY_RCU compilation issue - The var sysctl_panic_on_rcu_stall is now __read_mostly Cc: Jonathan Corbet <corbet@lwn.net> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Reviewed-by: Arnaldo Carvalho de Melo <acme@kernel.org> Tested-by: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>		2016-06-15 16:00:05 -07:00
..
bpf	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2016-05-31 22:28:28 -07:00
configs	…
debug	mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings	2016-02-22 08:51:37 +01:00
events	Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-05-25 17:05:40 -07:00
gcov	gcov: disable for COMPILE_TEST	2016-05-10 17:12:49 +02:00
irq	irqchip updates for 4.7-rc1:	2016-06-03 15:05:51 +02:00
livepatch	Merge branches 'for-4.7/core', 'for-4.7/livepatching-doc' and 'for-4.7/livepatching-ppc64' into for-linus	2016-05-17 12:06:35 +02:00
locking	add down_write_killable_nested()	2016-05-26 00:04:58 -04:00
power	PM / Hibernate: Call flush_icache_range() on pages restored in-place	2016-04-28 13:35:48 +01:00
printk	printk/nmi: flush NMI messages on the system panic	2016-05-20 17:58:30 -07:00
rcu	rcu: sysctl: Panic on RCU Stall	2016-06-15 16:00:05 -07:00
sched	Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-05-25 17:11:43 -07:00
time	timer: Export destroy_hrtimer_on_stack()	2016-05-31 11:44:08 -07:00
trace	Three more changes.	2016-05-22 19:40:39 -07:00
.gitignore	…
Kconfig.freezer	…
Kconfig.hz	…
Kconfig.locks	…
Kconfig.preempt	…
Makefile	ELF/MIPS build fix	2016-05-23 17:04:14 -07:00
acct.c	…
async.c	…
audit.c	Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit	2016-05-18 18:46:55 -07:00
audit.h	…
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	don't bother with ->d_inode->i_sb - it's always equal to ->d_sb	2016-04-10 17:11:51 -04:00
auditfilter.c	audit: Fix typo in comment	2016-02-08 11:25:39 -05:00
auditsc.c	Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit	2016-05-18 18:46:55 -07:00
backtracetest.c	…
bounds.c	…
capability.c	…
cgroup.c	cgroup: fix compile warning	2016-05-12 11:05:27 -04:00
cgroup_freezer.c	…
cgroup_pids.c	…
compat.c	…
configs.c	…
context_tracking.c	…
cpu.c	sched/hotplug: Make activate() the last hotplug step	2016-05-06 14:58:25 +02:00
cpu_pm.c	…
cpuset.c	cpuset: use static key better and convert to new API	2016-05-19 19:12:14 -07:00
crash_dump.c	…
cred.c	…
delayacct.c	…
dma.c	…
elfcore.c	…
exec_domain.c	…
exit.c	wait: allow sys_waitid() to accept __WNOTHREAD/__WCLONE/__WALL	2016-05-23 17:04:14 -07:00
extable.c	…
fork.c	mm: oom_reaper: remove some bloat	2016-05-26 15:35:44 -07:00
freezer.c	…
futex.c	x86: remove more uaccess_32.h complexity	2016-05-22 17:21:27 -07:00
futex_compat.c	ptrace: use fsuid, fsgid, effective creds for fs access checks	2016-01-20 17:09:18 -08:00
groups.c	…
hung_task.c	kernel/hung_task.c: use timeout diff when timeout is updated	2016-03-22 15:36:02 -07:00
irq_work.c	…
jump_label.c	…
kallsyms.c	kallsyms: add support for relative offsets in kallsyms address table	2016-03-15 16:55:16 -07:00
kcmp.c	ptrace: use fsuid, fsgid, effective creds for fs access checks	2016-01-20 17:09:18 -08:00
kcov.c	kcov: don't profile branches in kcov	2016-04-28 19:34:04 -07:00
kexec.c	s390/kexec: consolidate crash_map/unmap_reserved_pages() and arch_kexec_protect(unprotect)_crashkres()	2016-05-23 17:04:14 -07:00
kexec_core.c	s390/kexec: consolidate crash_map/unmap_reserved_pages() and arch_kexec_protect(unprotect)_crashkres()	2016-05-23 17:04:14 -07:00
kexec_file.c	kexec: introduce a protection mechanism for the crashkernel reserved memory	2016-05-23 17:04:14 -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
kmod.c	…
kprobes.c	…
ksysfs.c	…
kthread.c	…
latencytop.c	sched/debug: Make schedstats a runtime tunable that is disabled by default	2016-02-09 11:54:23 +01:00
membarrier.c	…
memremap.c	memremap: add arch specific hook for MEMREMAP_WB mappings	2016-04-04 10:26:41 +02:00
module-internal.h	…
module.c	module: preserve Elf information for livepatch modules	2016-04-01 15:00:10 +02:00
module_signing.c	KEYS: Move the point of trust determination to __key_link()	2016-04-11 22:43:43 +01:00
notifier.c	…
nsproxy.c	cgroup: introduce cgroup namespaces	2016-02-16 13:04:58 -05:00
padata.c	kernel/padata.c: hide unused functions	2016-05-19 19:12:14 -07:00
panic.c	printk/nmi: flush NMI messages on the system panic	2016-05-20 17:58:30 -07:00
params.c	…
pid.c	remove lots of IS_ERR_VALUE abuses	2016-05-27 15:26:11 -07:00
pid_namespace.c	…
profile.c	profile: hide unused functions when !CONFIG_PROC_FS	2016-03-22 15:36:02 -07:00
ptrace.c	ptrace: change __ptrace_unlink() to clear ->ptrace under ->siglock	2016-03-22 15:36:02 -07:00
range.c	…
reboot.c	…
relay.c	wrappers for ->i_mutex access	2016-01-22 18:04:28 -05:00
resource.c	/proc/iomem: only expose physical resource addresses to privileged users	2016-04-14 12:56:09 -07:00
seccomp.c	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2016-05-19 10:02:26 -07:00
signal.c	kernel/signal.c: convert printk(KERN_<LEVEL> ...) to pr_<level>(...)	2016-05-23 17:04:14 -07:00
smp.c	Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-03-15 13:50:29 -07:00
smpboot.c	cpu/hotplug: Unpark smpboot threads from the state machine	2016-03-01 20:36:56 +01:00
smpboot.h	cpu/hotplug: Create hotplug threads	2016-03-01 20:36:56 +01:00
softirq.c	arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections	2016-03-25 16:37:42 -07:00
stacktrace.c	…
stop_machine.c	…
sys.c	prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable	2016-05-23 17:04:14 -07:00
sys_ni.c	…
sysctl.c	rcu: sysctl: Panic on RCU Stall	2016-06-15 16:00:05 -07:00
sysctl_binary.c	kernel/sysctl_binary.c: use generic UUID library	2016-05-20 17:58:30 -07:00
task_work.c	…
taskstats.c	taskstats: use the libnl API to align nlattr on 64-bit	2016-04-23 20:13:25 -04:00
test_kprobes.c	…
torture.c	rcutorture: Dump trace buffer upon shutdown	2016-04-21 13:47:04 -07:00
tracepoint.c	kernel/...: convert pr_warning to pr_warn	2016-03-22 15:36:02 -07:00
tsacct.c	time, acct: Drop irq save & restore from __acct_update_integrals()	2016-02-29 09:53:09 +01:00
uid16.c	…
up.c	…
user-return-notifier.c	…
user.c	…
user_namespace.c	…
utsname.c	…
utsname_sysctl.c	…
watchdog.c	watchdog: don't run proc_watchdog_update if new value is same as old	2016-03-17 15:09:34 -07:00
workqueue.c	debugobjects: insulate non-fixup logic related to static obj from fixup callbacks	2016-05-19 19:12:14 -07:00
workqueue_internal.h	sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()	2016-03-02 10:28:47 -05:00