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
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
2016-05-31 22:28:28 -07:00
mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings
2016-02-22 08:51:37 +01:00
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: disable for COMPILE_TEST
2016-05-10 17:12:49 +02:00
irqchip updates for 4.7-rc1:
2016-06-03 15:05:51 +02:00
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
add down_write_killable_nested()
2016-05-26 00:04:58 -04:00
PM / Hibernate: Call flush_icache_range() on pages restored in-place
2016-04-28 13:35:48 +01:00
printk/nmi: flush NMI messages on the system panic
2016-05-20 17:58:30 -07:00
rcu: sysctl: Panic on RCU Stall
2016-06-15 16:00:05 -07:00
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
timer: Export destroy_hrtimer_on_stack()
2016-05-31 11:44:08 -07:00
Three more changes.
2016-05-22 19:40:39 -07:00
certs: add .gitignore to stop git nagging about x509_certificate_list
2015-10-21 15:18:35 +01:00
async: export current_is_async()
2015-11-19 17:51:48 +01:00
Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit
2016-05-18 18:46:55 -07:00
security: Make inode argument of inode_getsecid non-const
2015-12-24 11:09:39 -05:00
wrappers for ->i_mutex access
2016-01-22 18:04:28 -05:00
audit: cleanup prune_tree_thread
2016-04-04 09:46:47 -04:00
don't bother with ->d_inode->i_sb - it's always equal to ->d_sb
2016-04-10 17:11:51 -04:00
audit: Fix typo in comment
2016-02-08 11:25:39 -05:00
Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit
2016-05-18 18:46:55 -07:00
cgroup: fix compile warning
2016-05-12 11:05:27 -04:00
cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends
2015-12-03 10:24:08 -05:00
cgroup_pids: fix a typo.
2015-12-14 14:54:37 -05:00
context_tracking: Switch to new static_branch API
2015-11-24 09:56:43 +01:00
sched/hotplug: Make activate() the last hotplug step
2016-05-06 14:58:25 +02:00
cpuset: use static key better and convert to new API
2016-05-19 19:12:14 -07:00
kmemcg: account certain kmem allocations to memcg
2016-01-14 16:00:49 -08:00
kmemcg: account certain kmem allocations to memcg
2016-01-14 16:00:49 -08:00
wait: allow sys_waitid() to accept __WNOTHREAD/__WCLONE/__WALL
2016-05-23 17:04:14 -07:00
mm: oom_reaper: remove some bloat
2016-05-26 15:35:44 -07:00
x86: remove more uaccess_32.h complexity
2016-05-22 17:21:27 -07:00
ptrace: use fsuid, fsgid, effective creds for fs access checks
2016-01-20 17:09:18 -08:00
kernel/hung_task.c: use timeout diff when timeout is updated
2016-03-22 15:36:02 -07:00
treewide: Remove old email address
2015-11-23 09:44:58 +01:00
treewide: Remove old email address
2015-11-23 09:44:58 +01:00
kallsyms: add support for relative offsets in kallsyms address table
2016-03-15 16:55:16 -07:00
ptrace: use fsuid, fsgid, effective creds for fs access checks
2016-01-20 17:09:18 -08:00
kcov: don't profile branches in kcov
2016-04-28 19:34:04 -07:00
s390/kexec: consolidate crash_map/unmap_reserved_pages() and arch_kexec_protect(unprotect)_crashkres()
2016-05-23 17:04:14 -07:00
s390/kexec: consolidate crash_map/unmap_reserved_pages() and arch_kexec_protect(unprotect)_crashkres()
2016-05-23 17:04:14 -07:00
kexec: introduce a protection mechanism for the crashkernel reserved memory
2016-05-23 17:04:14 -07:00
kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILE
2016-01-20 17:09:18 -08:00
kmod: don't run async usermode helper as a child of kworker thread
2015-10-23 17:55:10 +09:00
rcu: Remove TINY_RCU bloat from pointless boot parameters
2015-12-07 16:59:37 -08:00
sched/debug: Make schedstats a runtime tunable that is disabled by default
2016-02-09 11:54:23 +01:00
ELF/MIPS build fix
2016-05-23 17:04:14 -07:00
memremap: add arch specific hook for MEMREMAP_WB mappings
2016-04-04 10:26:41 +02:00
module: preserve Elf information for livepatch modules
2016-04-01 15:00:10 +02:00
KEYS: Move the point of trust determination to __key_link()
2016-04-11 22:43:43 +01:00
cgroup: introduce cgroup namespaces
2016-02-16 13:04:58 -05:00
kernel/padata.c: hide unused functions
2016-05-19 19:12:14 -07:00
printk/nmi: flush NMI messages on the system panic
2016-05-20 17:58:30 -07:00
Nothing exciting, minor tweaks and cleanups.
2015-11-09 15:53:39 -08:00
remove lots of IS_ERR_VALUE abuses
2016-05-27 15:26:11 -07:00
profile: hide unused functions when !CONFIG_PROC_FS
2016-03-22 15:36:02 -07:00
ptrace: change __ptrace_unlink() to clear ->ptrace under ->siglock
2016-03-22 15:36:02 -07:00
wrappers for ->i_mutex access
2016-01-22 18:04:28 -05:00
/proc/iomem: only expose physical resource addresses to privileged users
2016-04-14 12:56:09 -07:00
Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
2016-05-19 10:02:26 -07:00
kernel/signal.c: convert printk(KERN_<LEVEL> ...) to pr_<level>(...)
2016-05-23 17:04:14 -07:00
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
cpu/hotplug: Unpark smpboot threads from the state machine
2016-03-01 20:36:56 +01:00
cpu/hotplug: Create hotplug threads
2016-03-01 20:36:56 +01:00
arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections
2016-03-25 16:37:42 -07:00
kernel/stop_machine.c: remove CONFIG_SMP dependencies
2016-01-16 11:17:24 -08:00
prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable
2016-05-23 17:04:14 -07:00
vfs: add copy_file_range syscall and vfs helper
2015-12-01 14:00:53 -05:00
rcu: sysctl: Panic on RCU Stall
2016-06-15 16:00:05 -07:00
kernel/sysctl_binary.c: use generic UUID library
2016-05-20 17:58:30 -07:00
taskstats: use the libnl API to align nlattr on 64-bit
2016-04-23 20:13:25 -04:00
rcutorture: Dump trace buffer upon shutdown
2016-04-21 13:47:04 -07:00
kernel/...: convert pr_warning to pr_warn
2016-03-22 15:36:02 -07:00
time, acct: Drop irq save & restore from __acct_update_integrals()
2016-02-29 09:53:09 +01:00
kernel/*: switch to memdup_user_nul()
2016-01-04 10:27:55 -05:00
watchdog: don't run proc_watchdog_update if new value is same as old
2016-03-17 15:09:34 -07:00
debugobjects: insulate non-fixup logic related to static obj from fixup callbacks
2016-05-19 19:12:14 -07:00
sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
2016-03-02 10:28:47 -05:00
088e9d253d