Vitaly Kuznetsov
08d78658f3
panic: release stale console lock to always get the logbuf printed out
...
In some cases we may end up killing the CPU holding the console lock
while still having valuable data in logbuf. E.g. I'm observing the
following:
- A crash is happening on one CPU and console_unlock() is being called on
some other.
- console_unlock() tries to print out the buffer before releasing the lock
and on slow console it takes time.
- in the meanwhile crashing CPU does lots of printk()-s with valuable data
(which go to the logbuf) and sends IPIs to all other CPUs.
- console_unlock() finishes printing previous chunk and enables interrupts
before trying to print out the rest, the CPU catches the IPI and never
releases console lock.
This is not the only possible case: in VT/fb subsystems we have many other
console_lock()/console_unlock() users. Non-masked interrupts (or
receiving NMI in case of extreme slowness) will have the same result.
Getting the whole console buffer printed out on crash should be top
priority.
[akpm@linux-foundation.org: tweak comment text]
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Baoquan He <bhe@redhat.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
..
bpf
bpf, verifier: annotate verbose printer with __printf
2015-11-03 11:29:56 -05:00
configs
kconfig: add xenconfig defconfig helper
2015-06-16 11:04:29 +01:00
debug
events
Merge branch 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2015-11-05 14:51:32 -08:00
gcov
gcov: add support for GCC 5.1
2015-06-30 19:44:57 -07:00
irq
Power management and ACPI updates for v4.4-rc1
2015-11-04 18:10:13 -08:00
livepatch
livepatch: Improve error handling in klp_disable_func()
2015-07-14 22:48:06 +02:00
locking
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
2015-11-06 17:50:42 -08:00
power
mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM
2015-11-06 17:50:42 -08:00
printk
printk: prevent userland from spoofing kernel messages
2015-11-06 17:50:42 -08:00
rcu
Merge branches 'doc.2015.10.06a', 'percpu-rwsem.2015.10.06a' and 'torture.2015.10.06a' into HEAD
2015-10-07 16:06:25 -07:00
sched
s390: A bunch of fixes and optimizations for interrupt and time
2015-11-05 16:26:26 -08:00
time
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-11-03 14:13:41 -08:00
trace
Merge branch 'for-4.4/core' of git://git.kernel.dk/linux-block
2015-11-04 20:28:10 -08:00
.gitignore
certs: add .gitignore to stop git nagging about x509_certificate_list
2015-10-21 15:18:35 +01:00
acct.c
acct: check FMODE_CAN_WRITE
2015-04-11 22:27:55 -04:00
async.c
audit.c
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
2015-11-06 17:50:42 -08:00
audit.h
audit: audit_tree_match can be boolean
2015-11-04 08:23:51 -05:00
audit_fsnotify.c
audit: clean simple fsnotify implementation
2015-08-06 16:14:53 -04:00
audit_tree.c
audit: audit_tree_match can be boolean
2015-11-04 08:23:51 -05:00
audit_watch.c
Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit
2015-09-08 13:34:59 -07:00
auditfilter.c
audit: fix comment block whitespace
2015-11-04 08:23:51 -05:00
auditsc.c
Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit
2015-09-08 13:34:59 -07:00
backtracetest.c
bounds.c
capability.c
kernel: conditionally support non-root users, groups and capabilities
2015-04-15 16:35:22 -07:00
cgroup.c
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
2015-11-06 17:50:42 -08:00
cgroup_freezer.c
cgroup: allow a cgroup subsystem to reject a fork
2015-07-14 17:29:23 -04:00
cgroup_pids.c
cgroup: add cgroup_subsys->free() method and use it to fix pids controller
2015-10-15 16:41:53 -04:00
compat.c
compat: cleanup coding in compat_get_bitmap() and compat_put_bitmap()
2015-06-04 23:57:18 +02:00
configs.c
context_tracking.c
context_tracking: Inherit TIF_NOHZ through forks instead of context switches
2015-05-07 12:02:51 +02:00
cpu.c
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-11-03 18:03:50 -08:00
cpu_pm.c
kernel/cpu_pm: fix cpu_cluster_pm_exit comment
2015-09-03 02:42:20 +02:00
cpuset.c
Merge branch 'akpm' (patches from Andrew)
2015-11-05 23:10:54 -08:00
crash_dump.c
cred.c
kernel/cred.c: remove unnecessary kdebug atomic reads
2015-09-10 13:29:01 -07:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
Remove rest of exec domains.
2015-04-12 21:03:31 +02:00
exit.c
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-11-03 18:03:50 -08:00
extable.c
kernel/extable.c: remove duplicated include
2015-09-10 13:29:01 -07:00
fork.c
Merge branch 'akpm' (patches from Andrew)
2015-11-05 23:10:54 -08:00
freezer.c
futex.c
driver core update for 4.4-rc1
2015-11-04 21:50:37 -08:00
futex_compat.c
groups.c
kernel: conditionally support non-root users, groups and capabilities
2015-04-15 16:35:22 -07:00
hung_task.c
kernel/hung_task.c: change hung_task.c to use for_each_process_thread()
2015-04-15 16:35:22 -07:00
irq_work.c
jump_label.c
locking/static_keys: Add selftest
2015-08-03 11:34:16 +02:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS
2015-05-12 09:46:00 +02:00
Kconfig.preempt
kexec.c
kexec: use file name as the output message prefix
2015-11-06 17:50:42 -08:00
kexec_core.c
kexec: use file name as the output message prefix
2015-11-06 17:50:42 -08:00
kexec_file.c
kexec: use file name as the output message prefix
2015-11-06 17:50:42 -08:00
kexec_internal.h
kexec: split kexec_file syscall code to kexec_file.c
2015-09-10 13:29:01 -07:00
kmod.c
kmod: don't run async usermode helper as a child of kworker thread
2015-10-23 17:55:10 +09:00
kprobes.c
perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safe
2015-08-04 10:16:54 +02:00
ksysfs.c
kexec: split kexec_load syscall from kexec core code
2015-09-10 13:29:01 -07:00
kthread.c
kernel/kthread.c:kthread_create_on_node(): clarify documentation
2015-09-04 16:54:41 -07:00
latencytop.c
Makefile
sys_membarrier(): system-wide memory barrier (generic, x86)
2015-09-11 15:21:34 -07:00
membarrier.c
sys_membarrier(): system-wide memory barrier (generic, x86)
2015-09-11 15:21:34 -07:00
memremap.c
memremap: fix highmem support
2015-10-26 16:55:56 -04:00
module-internal.h
module.c
module: Fix locking in symbol_put_addr()
2015-08-24 10:37:01 +09:30
module_signing.c
KEYS: Merge the type-specific data with the payload data
2015-10-21 15:18:36 +01:00
notifier.c
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-09-01 08:40:25 -07:00
nsproxy.c
padata.c
panic.c
panic: release stale console lock to always get the logbuf printed out
2015-11-06 17:50:42 -08:00
params.c
module: export param_free_charp()
2015-11-06 17:50:42 -08:00
pid.c
rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN()
2015-07-22 15:27:32 -07:00
pid_namespace.c
profile.c
mm: rename alloc_pages_exact_node() to __alloc_pages_node()
2015-09-08 15:35:28 -07:00
ptrace.c
seccomp, ptrace: add support for dumping seccomp filters
2015-10-27 19:55:13 -07:00
range.c
reboot.c
kexec: split kexec_load syscall from kexec core code
2015-09-10 13:29:01 -07:00
relay.c
kernel/relay.c: use kvfree() in relay_free_page_array()
2015-06-30 19:44:59 -07:00
resource.c
mm: enhance region_is_ram() to region_intersects()
2015-08-10 23:07:05 -04:00
seccomp.c
seccomp, ptrace: add support for dumping seccomp filters
2015-10-27 19:55:13 -07:00
signal.c
coredump: ensure all coredumping tasks have SIGNAL_GROUP_COREDUMP
2015-11-06 17:50:42 -08:00
smp.c
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
2015-11-06 17:50:42 -08:00
smpboot.c
stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()
2015-10-20 10:23:55 +02:00
smpboot.h
softirq.c
stacktrace.c
stop_machine.c
sched: Move cpu_active() tests from stop_two_cpus() into migrate_swap_stop()
2015-10-20 10:25:56 +02:00
sys.c
pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
2015-11-06 17:50:42 -08:00
sys_ni.c
mm: mlock: add new mlock system call
2015-11-05 19:34:48 -08:00
sysctl.c
kernel/watchdog.c: add sysctl knob hardlockup_panic
2015-11-05 19:34:48 -08:00
sysctl_binary.c
task_work.c
task_work: remove fifo ordering guarantee
2015-09-05 13:46:58 -07:00
taskstats.c
test_kprobes.c
torture.c
torture: Consolidate cond_resched_rcu_qs() into stutter_wait()
2015-10-06 11:25:01 -07:00
tracepoint.c
tsacct.c
uid16.c
up.c
user-return-notifier.c
user.c
user_namespace.c
capabilities: ambient capabilities
2015-09-04 16:54:41 -07:00
utsname.c
utsname_sysctl.c
watchdog.c
kernel/watchdog.c: fix race between proc_watchdog_thresh() and watchdog_timer_fn()
2015-11-05 19:34:48 -08:00
workqueue.c
Merge branch 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2015-11-05 14:16:27 -08:00
workqueue_internal.h