linux/kernel
Aaron Tomlin ed235875e2 kernel/watchdog.c: print traces for all cpus on lockup detection
A 'softlockup' is defined as a bug that causes the kernel to loop in
kernel mode for more than a predefined period to time, without giving
other tasks a chance to run.

Currently, upon detection of this condition by the per-cpu watchdog
task, debug information (including a stack trace) is sent to the system
log.

On some occasions, we have observed that the "victim" rather than the
actual "culprit" (i.e.  the owner/holder of the contended resource) is
reported to the user.  Often this information has proven to be
insufficient to assist debugging efforts.

To avoid loss of useful debug information, for architectures which
support NMI, this patch makes it possible to improve soft lockup
reporting.  This is accomplished by issuing an NMI to each cpu to obtain
a stack trace.

If NMI is not supported we just revert back to the old method.  A sysctl
and boot-time parameter is available to toggle this feature.

[dzickus@redhat.com: add CONFIG_SMP in certain areas]
[akpm@linux-foundation.org: additional CONFIG_SMP=n optimisations]
[mq@suse.cz: fix warning]
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jan Moskyto Matejka <mq@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-23 16:47:44 -07:00
..
debug kernel/printk: use symbolic defines for console loglevels 2014-06-04 16:54:17 -07:00
events Merge branch 'perf/core' into perf/urgent, to pick up the latest fixes 2014-06-14 14:10:08 +02:00
gcov gcov: add support for GCC 4.9 2014-06-10 15:34:46 -07:00
irq genirq: Improve documentation to match current implementation 2014-05-27 10:16:44 +02:00
locking Merge branch 'locking-urgent-for-linus.patch' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-06-21 07:06:02 -10:00
power x86, kaslr: boot-time selectable with hibernation 2014-06-16 23:30:44 +02:00
printk kernel/printk: use symbolic defines for console loglevels 2014-06-04 16:54:17 -07:00
rcu Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next 2014-06-03 12:57:53 -07:00
sched Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-06-12 19:42:15 -07:00
time Merge branch 'akpm' (patchbomb from Andrew) into next 2014-06-04 16:55:13 -07:00
trace One bug fix that goes back to 3.10. Accessing a non existent buffer 2014-06-12 21:07:25 -07:00
.gitignore Ignore generated file kernel/x509_certificate_list 2013-12-10 18:21:34 +00:00
Kconfig.freezer
Kconfig.hz kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS 2013-11-15 09:32:22 +09:00
Kconfig.locks locking/rwlocks: Introduce 'qrwlocks' - fair, queued rwlocks 2014-06-06 07:58:28 +02:00
Kconfig.preempt
Makefile Merge branch 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-03-31 14:13:25 -07:00
acct.c ipc, kernel: clear whitespace 2014-06-06 16:08:14 -07:00
async.c
audit.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-06-12 14:27:40 -07:00
audit.h audit: Use struct net not pid_t to remember the network namespce to reply in 2014-03-20 10:10:53 -04:00
audit_tree.c inotify: Fix reporting of cookies for inotify events 2014-02-18 11:17:17 +01:00
audit_watch.c inotify: Fix reporting of cookies for inotify events 2014-02-18 11:17:17 +01:00
auditfilter.c Merge git://git.infradead.org/users/eparis/audit 2014-04-12 12:38:53 -07:00
auditsc.c auditsc: audit_krule mask accesses need bounds checking 2014-06-10 08:44:40 -07:00
backtracetest.c kernel/backtracetest.c: replace no level printk by pr_info() 2014-06-04 16:54:14 -07:00
bounds.c mm: do not allocate page->ptl dynamically, if spinlock_t fits to long 2013-12-20 12:25:45 -08:00
capability.c fs,userns: Change inode_capable to capable_wrt_inode_uidgid 2014-06-10 13:57:22 -07:00
cgroup.c Merge branch 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-06-09 15:03:33 -07:00
cgroup_freezer.c cgroup: remove css_parent() 2014-05-16 13:22:48 -04:00
compat.c kernel/compat.c: use sizeof() instead of sizeof 2014-06-04 16:54:19 -07:00
configs.c
context_tracking.c x86/kprobes: Fix build errors and blacklist context_track_user 2014-06-14 09:07:44 +02:00
cpu.c More ACPI and power management updates for 3.16-rc1 2014-06-12 13:14:19 -07:00
cpu_pm.c
cpuset.c Merge branch 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-06-09 15:03:33 -07:00
crash_dump.c
cred.c
delayacct.c kernel/delayacct.c: remove redundant checking in __delayacct_add_tsk() 2013-11-13 12:09:12 +09:00
dma.c
elfcore.c switch elf_core_write_extra_phdrs() to dump_emit() 2013-11-09 00:16:23 -05:00
exec_domain.c kernel/exec_domain.c: code clean-up 2014-06-04 16:54:15 -07:00
exit.c signals: mv {dis,}allow_signal() from sched.h/exit.c to signal.[ch] 2014-06-06 16:08:11 -07:00
extable.c asmlinkage: Make main_extable_sort_needed visible 2014-02-13 18:13:22 -08:00
fork.c ptrace: fix fork event messages across pid namespaces 2014-06-06 16:08:11 -07:00
freezer.c libata, freezer: avoid block device removal while system is frozen 2013-12-19 13:50:32 -05:00
futex.c Merge branch 'next' (accumulated 3.16 merge window patches) into master 2014-06-08 11:31:16 -07:00
futex_compat.c compat: Get rid of (get|put)_compat_time(val|spec) 2014-02-02 14:09:12 -08:00
groups.c kernel/groups.c: remove return value of set_groups 2014-04-03 16:21:05 -07:00
hrtimer.c Merge branch 'perf/urgent' into perf/core, to resolve conflict and to prepare for new patches 2014-06-06 07:55:06 +02:00
hung_task.c kernel/hung_task.c: convert simple_strtoul to kstrtouint 2014-06-04 16:54:15 -07:00
irq_work.c perf/x86: Warn to early_printk() in case irq_work is too slow 2014-02-21 21:49:07 +01:00
itimer.c
jump_label.c static_key: WARN on usage before jump_label_init was called 2013-10-19 19:45:35 -04:00
kallsyms.c kernel: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:36:11 -07:00
kcmp.c
kexec.c kexec: save PG_head_mask in VMCOREINFO 2014-06-23 16:47:43 -07:00
kmod.c signals: change wait_for_helper() to use kernel_sigaction() 2014-06-06 16:08:12 -07:00
kprobes.c kprobes: Show blacklist entries via debugfs 2014-04-24 10:26:41 +02:00
ksysfs.c kobject: Make support for uevent_helper optional. 2014-04-25 12:00:49 -07:00
kthread.c kthread: fix return value of kthread_create() upon SIGKILL. 2014-06-04 16:53:51 -07:00
latencytop.c kernel/latencytop.c: convert seq_printf to seq_puts 2014-06-04 16:54:15 -07:00
module-internal.h KEYS: Separate the kernel signature checking keyring from module signing 2013-09-25 17:17:01 +01:00
module.c Most of this is cleaning up various driver sysfs permissions so we can 2014-06-11 16:09:14 -07:00
module_signing.c keys: change asymmetric keys to use common hash definitions 2013-10-25 17:15:18 -04:00
notifier.c kprobes, notifier: Use NOKPROBE_SYMBOL macro in notifier 2014-04-24 10:26:39 +02:00
nsproxy.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-09-07 14:35:32 -07:00
padata.c padata: Fix wrong usage of rcu_dereference() 2013-12-05 21:28:42 +08:00
panic.c kernel/panic.c: add "crash_kexec_post_notifiers" option for kdump after panic_notifers 2014-06-06 16:08:12 -07:00
params.c param: hand arguments after -- straight to init 2014-04-28 11:48:34 +09:30
pid.c pidns: fix free_pid() to handle the first fork failure 2013-09-30 14:31:03 -07:00
pid_namespace.c pid_namespace: pidns_get() should check task_active_pid_ns() != NULL 2014-04-02 16:20:21 -07:00
posix-cpu-timers.c posix-timers: Convert abuses of BUG_ON to WARN_ON 2013-12-09 16:56:29 +01:00
posix-timers.c
profile.c kernel/profile.c: use static const char instead of static char 2014-06-06 16:08:13 -07:00
ptrace.c kernel/compat: convert to COMPAT_SYSCALL_DEFINE 2014-03-06 15:35:10 +01:00
range.c
reboot.c kernel/reboot.c: convert simple_strtoul to kstrtoint 2014-06-04 16:54:15 -07:00
relay.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
res_counter.c kernel/res_counter.c: replace simple_strtoull by kstrtoull 2014-06-04 16:54:15 -07:00
resource.c resources: Clarify sanity check message 2014-05-23 10:47:21 -06:00
seccomp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-06-12 14:27:40 -07:00
signal.c signals: introduce kernel_sigaction() 2014-06-06 16:08:12 -07:00
smp.c CPU hotplug, smp: flush any pending IPI callbacks before CPU offline 2014-06-23 16:47:43 -07:00
smpboot.c
smpboot.h
softirq.c Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu 2014-05-22 11:36:10 +02:00
stacktrace.c
stop_machine.c kernel/stop_machine.c: kernel-doc warning fix 2014-06-04 16:54:15 -07:00
sys.c sched: Consolidate open coded implementations of nice level frobbing into nice_to_rlimit() and rlimit_to_nice() 2014-05-22 11:16:36 +02:00
sys_ni.c sys_sgetmask/sys_ssetmask: add CONFIG_SGETMASK_SYSCALL 2014-06-04 16:54:14 -07:00
sysctl.c kernel/watchdog.c: print traces for all cpus on lockup detection 2014-06-23 16:47:44 -07:00
sysctl_binary.c kernel/sysctl_binary.c: use scnprintf() instead of snprintf() 2013-11-13 12:09:33 +09:00
system_certificates.S KEYS: correct alignment of system_certificate_list content in assembly file 2013-12-10 18:25:28 +00:00
system_keyring.c KEYS: correct alignment of system_certificate_list content in assembly file 2013-12-10 18:25:28 +00:00
task_work.c task_work: documentation 2013-09-11 15:58:27 -07:00
taskstats.c genetlink: only pass array to genl_register_family_with_ops() 2013-11-19 16:39:05 -05:00
test_kprobes.c
time.c
timeconst.bc
timer.c timer: Prevent overflow in apply_slack 2014-04-30 13:46:17 +02:00
torture.c torture: Remove __init from torture_init_begin/end 2014-05-14 09:46:30 -07:00
tracepoint.c kernel/tracepoint.c: kernel-doc fixes 2014-06-04 16:54:15 -07:00
tsacct.c
uid16.c userns: Kill nsown_capable it makes the wrong thing easy 2013-08-30 23:44:11 -07:00
up.c smp: Rename __smp_call_function_single() to smp_call_function_single_async() 2014-02-24 14:47:15 -08:00
user-return-notifier.c
user.c kernel/user.c: drop unused field 'files' from user_struct 2014-06-04 16:54:16 -07:00
user_namespace.c kernel/user_namespace.c: kernel-doc/checkpatch fixes 2014-06-06 16:08:13 -07:00
utsname.c userns: Kill nsown_capable it makes the wrong thing easy 2013-08-30 23:44:11 -07:00
utsname_sysctl.c sysctl: convert use of typedef ctl_table to struct ctl_table 2014-06-06 16:08:16 -07:00
watchdog.c kernel/watchdog.c: print traces for all cpus on lockup detection 2014-06-23 16:47:44 -07:00
workqueue.c Merge branch 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2014-06-09 14:56:49 -07:00
workqueue_internal.h workqueue: rename manager_mutex to attach_mutex 2014-05-20 10:59:32 -04:00