Petr Mladek
adc56dbfc4
printk/console: Allow to disable console output by using console="" or console=null ...
commit 3cffa06aeef7ece30f6b5ac0ea51f264e8fea4d0 upstream.
The commit 48021f98130880dd74 ("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 14:43:03 +01:00
bpf: Fix integer overflow in prealloc_elems_and_freelist()
2021-10-13 10:08:18 +02:00
cgroup/cpuset: Fix a partition bug with hotplug
2021-09-15 09:47:32 +02:00
kdb: Make memory allocations more robust
2021-03-04 10:26:10 +01:00
dma-debug: fix sg checks in debug_dma_map_sg()
2021-10-27 09:54:25 +02:00
events: Reuse value read using READ_ONCE instead of re-reading it
2021-09-22 12:26:41 +02:00
gcov: re-fix clang-11+ support
2021-04-14 08:24:10 +02:00
genirq/timings: Fix error return code in irq_timings_test_irqs()
2021-09-15 09:47:29 +02:00
locking/mutex: Fix HANDOFF condition
2021-09-15 09:47:25 +02:00
PM: EM: Increase energy calculation precision
2021-09-15 09:47:33 +02:00
printk/console: Allow to disable console output by using console="" or console=null
2021-11-12 14:43:03 +01:00
rcu/tree: Handle VM stoppage in stall detection
2021-09-15 09:47:26 +02:00
cpufreq: schedutil: Use kobject release() method to free sugov_tunables
2021-10-06 15:42:29 +02:00
Revert "posix-cpu-timers: Force next expiration recalc after itimer reset"
2021-09-16 12:56:13 +02:00
tracing: Have all levels of checks prevent recursion
2021-10-27 09:54:29 +02:00
kbuild: update config_data.gz only when the content of .config is changed
2021-05-11 14:04:16 +02:00
audit: fix a net reference leak in audit_list_rules_send()
2020-06-22 09:30:59 +02:00
audit: fix a net reference leak in audit_list_rules_send()
2020-06-22 09:30:59 +02:00
audit: move put_tree() to avoid trim_trees refcount underflow and UAF
2021-09-03 10:08:16 +02:00
audit: CONFIG_CHANGE don't log internal bookkeeping as an event
2020-10-01 13:17:32 +02:00
audit: fix a net reference leak in audit_list_rules_send()
2020-06-22 09:30:59 +02:00
audit: fix possible null-pointer dereference in audit_filter_rules
2021-10-27 09:54:27 +02:00
cpu/hotplug: Cure the cpusets trainwreck
2021-07-19 08:53:15 +02:00
kernel/cpu_pm: Fix uninitted local in cpu_pm
2020-06-22 09:31:22 +02:00
keys: Fix request_key() cache
2020-01-17 19:48:42 +01:00
don't dump the threads that had been already exiting when zapped.
2020-11-18 19:20:31 +01:00
fail_function: Remove a redundant mutex unlock
2020-11-24 13:29:18 +01:00
mm/hugetlb: initialize hugetlb_usage in mm_init
2021-09-22 12:26:37 +02:00
Revert "libata, freezer: avoid block device removal while system is frozen"
2019-10-06 09:11:37 -06:00
mm, futex: fix shared futex pgoff on shmem huge page
2021-06-30 08:47:55 -04:00
kbuild: add variables for compression tools
2020-09-03 11:27:10 +02:00
kallsyms: Refactor kallsyms_show_value() to take cred
2020-07-16 08:16:44 +02:00
exec: Transform exec_update_mutex into a rw_semaphore
2021-01-09 13:44:55 +01:00
kernel: kexec: remove the lock operation of system_transition_mutex
2021-02-03 23:25:56 +01:00
kexec_elf: support 32 bit ELF files
2019-09-06 23:58:44 +02:00
kernel: kexec_file: fix error return code of kexec_calculate_store_digests()
2021-05-19 10:08:28 +02:00
kmod: make request_module() return an error when autoloading is disabled
2020-04-17 10:50:22 +02:00
tracing/kprobe: Fix to support kretprobe events on unloaded modules
2021-02-13 13:52:54 +01:00
kthread: Fix PF_KTHREAD vs to_kthread() race
2021-09-12 08:56:39 +02:00
kbuild: update config_data.gz only when the content of .config is changed
2021-05-11 14:04:16 +02:00
module: limit enabling module.sig_enforce
2021-06-30 08:47:42 -04:00
module: harden ELF info handling
2021-04-07 14:47:38 +02:00
module: harden ELF info handling
2021-04-07 14:47:38 +02:00
kernel/notifier.c: intercept duplicate registrations to avoid infinite loops
2020-10-01 13:17:23 +02:00
padata: add separate cpuhp node for CPUHP_PADATA_DEAD
2020-06-17 16:40:22 +02:00
panic: ensure preemption is disabled during panic()
2019-10-07 15:47:19 -07:00
memcg: enable accounting for pids in nested pid namespaces
2021-09-22 12:26:37 +02:00
profiling: fix shift-out-of-bounds bugs
2021-09-26 14:07:09 +02:00
ptrace: make ptrace() fail if the tracee changed its pid unexpectedly
2021-05-26 12:05:15 +02:00
reboot: fix overflow parsing reboot cpu number
2020-11-18 19:20:30 +01:00
kernel/relay.c: fix memleak on destroy relay channel
2020-08-26 10:40:51 +02:00
/dev/mem: Revoke mappings when a driver claims the region
2020-06-24 17:50:35 +02:00
seccomp: Add missing return in non-void function
2021-03-04 10:26:45 +01:00
ptrace: fix task_join_group_stop() for the case when current is traced
2020-11-10 12:37:24 +01:00
smp: Fix smp_call_function_single_async prototype
2021-05-14 09:44:33 +02:00
kthread: Extract KTHREAD_IS_PER_CPU
2021-02-07 15:35:49 +01:00
stacktrace: Don't skip first entry on noncurrent tasks
2019-11-04 21:19:25 +01:00
stop_machine: Avoid potential race behaviour
2019-10-17 12:47:12 +02:00
prctl: allow to setup brk for et_dyn executables
2021-09-26 14:07:08 +02:00
kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec()
2020-10-01 13:17:10 +02:00
sysctl.c: fix underflow value setting risk in vm_table
2021-03-17 17:03:45 +01:00
taskstats: fix data-race
2020-01-09 10:19:54 +01:00
tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing
2021-07-14 16:53:08 +02:00
usermodehelper: reset umask to default before executing user process
2020-10-14 10:32:58 +02:00
smp: Fix smp_call_function_single_async prototype
2021-05-14 09:44:33 +02:00
watchdog/softlockup: Enforce that timestamp is valid on boot
2020-02-24 08:36:52 +01:00
workqueue: Fix possible memory leaks in wq_numa_init()
2021-09-22 12:26:30 +02:00
adc56dbfc4