Petr Mladek ab4af56ae2 printk/console: Allow to disable console output by using console="" or console=null ... commit 3cffa06aeef7ece30f6b5ac0ea51f264e8fea4d0 upstream. The commit 48021f9813 ("printk: handle blank console arguments passed in.") prevented crash caused by empty console= parameter value. Unfortunately, this value is widely used on Chromebooks to disable the console output. The above commit caused performance regression because the messages were pushed on slow console even though nobody was watching it. Use ttynull driver explicitly for console="" and console=null parameters. It has been created for exactly this purpose. It causes that preferred_console is set. As a result, ttySX and ttyX are not used as a fallback. And only ttynull console gets registered by default. It still allows to register other consoles either by additional console= parameters or SPCR. It prevents regression because it worked this way even before. Also it is a sane semantic. Preventing output on all consoles should be done another way, for example, by introducing mute_console parameter. Link: https://lore.kernel.org/r/20201006025935.GA597@jagdpanzerIV.localdomain Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20201111135450.11214-3-pmladek@suse.com Cc: Yi Fan <yfa@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-11-12 14:58:33 +01:00
..
bpf	bpf: Fix error usage of map_fd and fdget() in generic_map_update_batch()	2021-11-02 19:48:21 +01:00
cgroup	cgroup: Fix memory leak caused by missing cgroup_bpf_offline	2021-11-02 19:48:21 +01:00
configs
debug	kgdb: fix to kill breakpoints on initmem after boot	2021-03-04 11:38:46 +01:00
dma	dma-debug: fix sg checks in debug_dma_map_sg()	2021-10-27 09:56:47 +02:00
entry	KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest	2021-10-06 15:55:49 +02:00
events	perf/core: fix userpage->time_enabled of inactive events	2021-10-17 10:43:33 +02:00
gcov	gcov: re-fix clang-11+ support	2021-04-14 08:41:58 +02:00
irq	genirq/timings: Fix error return code in irq_timings_test_irqs()	2021-09-15 09:50:29 +02:00
kcsan	kcsan: Fix debugfs initcall return type	2021-05-26 12:06:54 +02:00
livepatch	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
locking	locking/lockdep: Mark local_lock_t	2021-09-15 09:50:41 +02:00
power	PM: EM: Increase energy calculation precision	2021-09-15 09:50:37 +02:00
printk	printk/console: Allow to disable console output by using console="" or console=null	2021-11-12 14:58:33 +01:00
rcu	rcu: Fix macro name CONFIG_TASKS_RCU_TRACE	2021-09-18 13:40:19 +02:00
sched	sched/scs: Reset the shadow stack when idle_task_exit	2021-10-27 09:56:55 +02:00
time	Revert "posix-cpu-timers: Force next expiration recalc after itimer reset"	2021-09-16 12:51:23 +02:00
trace	tracing: Have all levels of checks prevent recursion	2021-10-27 09:56:56 +02:00
.gitignore	kbuild: update config_data.gz only when the content of .config is changed	2021-05-11 14:47:37 +02:00
acct.c	kernel: acct.c: fix some kernel-doc nits	2020-10-16 11:11:19 -07:00
async.c
audit_fsnotify.c	fsnotify: generalize handle_inode_event()	2020-12-30 11:54:18 +01:00
audit_tree.c	audit: move put_tree() to avoid trim_trees refcount underflow and UAF	2021-09-03 10:09:31 +02:00
audit_watch.c	fsnotify: generalize handle_inode_event()	2020-12-30 11:54:18 +01:00
audit.c
audit.h
auditfilter.c
auditsc.c	audit: fix possible null-pointer dereference in audit_filter_rules	2021-10-27 09:56:52 +02:00
backtracetest.c
bounds.c
capability.c
compat.c
configs.c
context_tracking.c
cpu_pm.c	PM: cpu: Make notifier chain use a raw_spinlock_t	2021-09-15 09:50:40 +02:00
cpu.c	cpu/hotplug: Cure the cpusets trainwreck	2021-07-19 09:44:59 +02:00
crash_core.c	crash_core, vmcoreinfo: append 'SECTION_SIZE_BITS' to vmcoreinfo	2021-06-23 14:42:52 +02:00
crash_dump.c
cred.c	Revert "Add a reference to ucounts for each cred"	2021-09-08 08:49:00 +02:00
delayacct.c
dma.c
exec_domain.c
exit.c	kernel/io_uring: cancel io_uring before task works	2021-01-30 13:55:18 +01:00
extable.c
fail_function.c	fail_function: Remove a redundant mutex unlock	2020-11-19 11:58:16 -08:00
fork.c	mm/hugetlb: initialize hugetlb_usage in mm_init	2021-09-18 13:40:36 +02:00
freezer.c	Revert "kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing"	2021-04-07 15:00:14 +02:00
futex.c	mm, futex: fix shared futex pgoff on shmem huge page	2021-06-30 08:47:29 -04:00
gen_kheaders.sh
groups.c
hung_task.c	kernel/hung_task.c: make type annotations consistent	2020-11-02 12:14:19 -08:00
iomem.c
irq_work.c
jump_label.c	jump_label: Fix jump_label_text_reserved() vs __init	2021-07-20 16:05:58 +02:00
kallsyms.c	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
kcmp.c	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:46:24 +01:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kexec_core.c	kernel: kexec: remove the lock operation of system_transition_mutex	2021-02-03 23:28:37 +01:00
kexec_elf.c
kexec_file.c	kernel: kexec_file: fix error return code of kexec_calculate_store_digests()	2021-05-19 10:13:09 +02:00
kexec_internal.h
kexec.c
kheaders.c
kmod.c
kprobes.c	kprobes: Fix to delay the kprobes jump optimization	2021-03-04 11:38:35 +01:00
ksysfs.c
kthread.c	kthread: Fix PF_KTHREAD vs to_kthread() race	2021-09-03 10:09:31 +02:00
latencytop.c
Makefile	kbuild: update config_data.gz only when the content of .config is changed	2021-05-11 14:47:37 +02:00
module_signature.c	module: harden ELF info handling	2021-03-25 09:04:11 +01:00
module_signing.c	module: harden ELF info handling	2021-03-25 09:04:11 +01:00
module-internal.h
module.c	module: limit enabling module.sig_enforce	2021-06-30 08:47:15 -04:00
notifier.c
nsproxy.c
padata.c
panic.c	panic: don't dump stack twice on warn	2020-11-14 11:26:04 -08:00
params.c	params: Replace zero-length array with flexible-array member	2020-10-29 17:22:59 -05:00
pid_namespace.c	memcg: enable accounting for pids in nested pid namespaces	2021-09-18 13:40:36 +02:00
pid.c	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:46:24 +01:00
profile.c	profiling: fix shift-out-of-bounds bugs	2021-09-26 14:08:58 +02:00
ptrace.c	ptrace: make ptrace() fail if the tracee changed its pid unexpectedly	2021-05-26 12:06:49 +02:00
range.c	kernel.h: split out min()/max() et al. helpers	2020-10-16 11:11:19 -07:00
reboot.c	reboot: fix overflow parsing reboot cpu number	2020-11-14 11:26:03 -08:00
regset.c
relay.c	kernel/relay.c: drop unneeded initialization	2020-10-16 11:11:22 -07:00
resource.c	kernel/resource: make walk_mem_res() find all busy IORESOURCE_MEM resources	2021-05-19 10:13:09 +02:00
rseq.c	KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest	2021-10-06 15:55:49 +02:00
scftorture.c
scs.c
seccomp.c	seccomp: Fix setting loaded filter count during TSYNC	2021-08-18 08:59:06 +02:00
signal.c	ptrace: fix task_join_group_stop() for the case when current is traced	2020-11-02 12:14:19 -08:00
smp.c	smp: Fix smp_call_function_single_async prototype	2021-05-14 09:50:46 +02:00
smpboot.c	sched/core: Initialize the idle task with preemption disabled	2021-07-14 16:55:50 +02:00
smpboot.h
softirq.c
stackleak.c
stacktrace.c
static_call.c	static_call: Fix unused variable warn w/o MODULE	2021-09-08 08:49:00 +02:00
stop_machine.c	stop_machine, rcu: Mark functions as notrace	2020-10-26 12:12:27 +01:00
sys_ni.c	mm/madvise: introduce process_madvise() syscall: an external memory hinting API	2020-10-18 09:27:10 -07:00
sys.c	prctl: allow to setup brk for et_dyn executables	2021-09-26 14:08:57 +02:00
sysctl-test.c
sysctl.c	sysctl.c: fix underflow value setting risk in vm_table	2021-03-17 17:06:25 +01:00
task_work.c	task_work: cleanup notification modes	2020-10-17 15:05:30 -06:00
taskstats.c
test_kprobes.c
torture.c
tracepoint.c	tracepoint: Use rcu get state and cond sync for static call updates	2021-09-03 10:09:30 +02:00
tsacct.c
ucount.c	Revert "Add a reference to ucounts for each cred"	2021-09-08 08:49:00 +02:00
uid16.c
uid16.h
umh.c
up.c	smp: Fix smp_call_function_single_async prototype	2021-05-14 09:50:46 +02:00
user_namespace.c	Revert "Add a reference to ucounts for each cred"	2021-09-08 08:49:00 +02:00
user-return-notifier.c
user.c
usermode_driver.c	bpf: Fix umd memory leak in copy_process()	2021-03-30 14:32:03 +02:00
utsname_sysctl.c
utsname.c
watch_queue.c
watchdog_hld.c
watchdog.c	watchdog: fix barriers when printing backtraces from all CPUs	2021-05-19 10:13:00 +02:00
workqueue_internal.h
workqueue.c	workqueue: Fix possible memory leaks in wq_numa_init()	2021-09-18 13:40:23 +02:00