Sergey Senozhatsky 884e370ea8 printk: CON_PRINTBUFFER console registration is a bit racy ... CON_PRINTBUFFER console registration requires us to do several preparation steps: - Rollback console_seq to replay logbuf messages which were already seen on other consoles; - Set exclusive_console flag so console_unlock() will ->write() logbuf messages only to the exclusive_console driver. The way we do it, however, is a bit racy logbuf_lock_irqsave(flags); console_seq = syslog_seq; console_idx = syslog_idx; logbuf_unlock_irqrestore(flags); << preemption enabled << irqs enabled exclusive_console = newcon; console_unlock(); We rollback console_seq under logbuf_lock with IRQs disabled, but we set exclusive_console with local IRQs enabled and logbuf unlocked. If the system oops-es or panic-s before we set exclusive_console - and given that we have IRQs and preemption enabled there is such a possibility - we will re-play all logbuf messages to every registered console, which may be a bit annoying and time consuming. Move exclusive_console assignment to the same IRQs-disabled and logbuf_lock-protected section where we rollback console_seq. Link: http://lkml.kernel.org/r/20180928095304.9972-1-sergey.senozhatsky@gmail.com To: Steven Rostedt <rostedt@goodmis.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>		2018-10-02 15:20:50 +02:00
..
bpf	bpf: avoid misuse of psock when TCP_ULP_BPF collides with another ULP	2018-09-02 22:31:10 +02:00
cgroup	Merge branch 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2018-08-24 13:19:27 -07:00
configs
debug
dma	kernel/dma/direct: take DMA offset into account in dma_direct_supported	2018-09-01 15:42:28 +02:00
events	treewide: convert ISO_8859-1 text comments to utf-8	2018-08-23 18:48:43 -07:00
gcov
irq
livepatch
locking
power
printk	printk: CON_PRINTBUFFER console registration is a bit racy	2018-10-02 15:20:50 +02:00
rcu
sched
time	clocksource: Revert "Remove kthread"	2018-09-06 23:38:35 +02:00
trace	Masami found an off by one bug in the code that keeps "notrace" functions	2018-08-23 13:07:00 -07:00
.gitignore
acct.c
async.c
audit_fsnotify.c
audit_tree.c
audit_watch.c
audit.c
audit.h
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c	cpu/hotplug: Prevent state corruption on error rollback	2018-09-06 15:21:38 +02:00
crash_core.c
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c
extable.c
fail_function.c
fork.c	mm: respect arch_dup_mmap() return value	2018-09-04 16:45:02 -07:00
freezer.c
futex_compat.c
futex.c
groups.c
hung_task.c
iomem.c
irq_work.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kexec_core.c
kexec_file.c
kexec_internal.h
kexec.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
Makefile
memremap.c	libnvdimm-for-4.19_dax-memory-failure	2018-08-25 18:43:59 -07:00
module_signing.c
module-internal.h
module.c
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid_namespace.c
pid.c
profile.c
ptrace.c
range.c
reboot.c
relay.c
resource.c
rseq.c
seccomp.c
signal.c
smp.c
smpboot.c
smpboot.h
softirq.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c	Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2018-08-24 09:25:39 -07:00
sysctl_binary.c
sysctl.c	namei: allow restricted O_CREAT of FIFOs and regular files	2018-08-23 18:48:43 -07:00
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c
up.c
user_namespace.c
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog_hld.c	watchdog: Mark watchdog touch functions as notrace	2018-08-30 12:56:40 +02:00
watchdog.c	watchdog: Mark watchdog touch functions as notrace	2018-08-30 12:56:40 +02:00
workqueue_internal.h
workqueue.c	watchdog: Mark watchdog touch functions as notrace	2018-08-30 12:56:40 +02:00