Peter Collingbourne 23174ac899 serial: Lock console when calling into driver before registration ... [ Upstream commit 801410b26a ] During the handoff from earlycon to the real console driver, we have two separate drivers operating on the same device concurrently. In the case of the 8250 driver these concurrent accesses cause problems due to the driver's use of banked registers, controlled by LCR.DLAB. It is possible for the setup(), config_port(), pm() and set_mctrl() callbacks to set DLAB, which can cause the earlycon code that intends to access TX to instead access DLL, leading to missed output and corruption on the serial line due to unintended modifications to the baud rate. In particular, for setup() we have: univ8250_console_setup() -> serial8250_console_setup() -> uart_set_options() -> serial8250_set_termios() -> serial8250_do_set_termios() -> serial8250_do_set_divisor() For config_port() we have: serial8250_config_port() -> autoconfig() For pm() we have: serial8250_pm() -> serial8250_do_pm() -> serial8250_set_sleep() For set_mctrl() we have (for some devices): serial8250_set_mctrl() -> omap8250_set_mctrl() -> __omap8250_set_mctrl() To avoid such problems, let's make it so that the console is locked during pre-registration calls to these callbacks, which will prevent the earlycon driver from running concurrently. Remove the partial solution to this problem in the 8250 driver that locked the console only during autoconfig_irq(), as this would result in a deadlock with the new approach. The console continues to be locked during autoconfig_irq() because it can only be called through uart_configure_port(). Although this patch introduces more locking than strictly necessary (and in particular it also locks during the call to rs485_config() which is not affected by this issue as far as I can tell), it follows the principle that it is the responsibility of the generic console code to manage the earlycon handoff by ensuring that earlycon and real console driver code cannot run concurrently, and not the individual drivers. Signed-off-by: Peter Collingbourne <pcc@google.com> Reviewed-by: John Ogness <john.ogness@linutronix.de> Link: https://linux-review.googlesource.com/id/I7cf8124dcebf8618e6b2ee543fa5b25532de55d8 Fixes: 1da177e4c3 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240304214350.501253-1-pcc@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2024-04-03 15:11:17 +02:00
..
bpf	bpf: report RCU QS in cpumap kthread	2024-03-26 18:18:59 -04:00
cgroup	cgroup: Fixes for v6.7-rc4	2023-12-07 12:42:40 -08:00
configs	hardening: Provide Kconfig fragments for basic options	2023-09-22 09:50:55 -07:00
debug	kdb: Fix a potential buffer overflow in kdb_local()	2024-01-25 15:45:30 -08:00
dma	dma-mapping: clear dev->dma_mem to NULL after freeing it	2024-01-25 15:44:53 -08:00
entry	entry: Remove empty addr_limit_user_check()	2023-08-23 10:32:39 +02:00
events	perf: Fix the nr_addr_filters fix	2024-02-05 20:17:06 +00:00
futex	futex: Prevent the reuse of stale pi_state	2024-01-31 16:21:18 -08:00
gcov	gcov: annotate struct gcov_iterator with __counted_by	2023-10-18 14:43:22 -07:00
irq	genirq: Initialize resend_node hlist for all interrupt descriptors	2024-01-31 16:21:21 -08:00
kcsan	mm: delete checks for xor_unlock_is_negative_byte()	2023-10-18 14:34:17 -07:00
livepatch	livepatch: Fix missing newline character in klp_resolve_symbols()	2023-09-20 11:24:18 +02:00
locking	locking/osq_lock: Clarify osq_wait_next()	2023-12-30 10:25:51 -08:00
module	modules: wait do_free_init correctly	2024-03-26 18:18:42 -04:00
power	PM: suspend: Set mem_sleep_current during kernel command line setup	2024-04-03 15:11:13 +02:00
printk	serial: Lock console when calling into driver before registration	2024-04-03 15:11:17 +02:00
rcu	rcu/exp: Handle RCU expedited grace period kworker allocation failure	2024-03-26 18:17:59 -04:00
sched	sched/fair: Take the scheduling domain into account in select_idle_core()	2024-03-26 18:18:02 -04:00
time	timekeeping: Fix cross-timestamp interpolation for non-x86	2024-03-26 18:18:02 -04:00
trace	fprobe: Fix to allocate entry_data_size buffer with rethook instances	2024-03-06 14:53:57 +00:00
.gitignore
acct.c	fs: rename __mnt_{want,drop}_write*() helpers	2023-09-11 15:05:50 +02:00
async.c	async: Introduce async_schedule_dev_nocall()	2024-01-31 16:20:53 -08:00
audit_fsnotify.c
audit_tree.c	As usual, lots of singleton and doubleton patches all over the tree and	2023-11-02 20:53:31 -10:00
audit_watch.c	audit: don't WARN_ON_ONCE(!current->mm) in audit_exe_compare()	2023-11-14 17:34:27 -05:00
audit.c	audit: Send netlink ACK before setting connection in auditd_set	2024-02-05 20:16:45 +00:00
audit.h	audit: correct audit_filter_inodes() definition	2023-07-21 12:17:25 -04:00
auditfilter.c	audit: move trailing statements to next line	2023-08-15 18:16:14 -04:00
auditsc.c	audit,io_uring: io_uring openat triggers audit reference count underflow	2023-10-13 18:34:46 +02:00
backtracetest.c
bounds.c	bounds: support non-power-of-two CONFIG_NR_CPUS	2024-04-03 15:11:11 +02:00
capability.c	lsm: constify the 'target' parameter in security_capget()	2023-08-08 16:48:47 -04:00
cfi.c
compat.c	sched_getaffinity: don't assume 'cpumask_size()' is fully initialized	2023-03-14 19:32:38 -07:00
configs.c
context_tracking.c	locking/atomic: treewide: use raw_atomic*_<op>()	2023-06-05 09:57:20 +02:00
cpu_pm.c	cpuidle, cpu_pm: Remove RCU fiddling from cpu_pm_{enter,exit}()	2023-01-13 11:48:15 +01:00
cpu.c	- Do the push of pending hrtimers away from a CPU which is being	2023-11-19 13:35:07 -08:00
crash_core.c	kdump: defer the insertion of crashkernel resources	2024-01-31 16:21:02 -08:00
crash_dump.c
cred.c	cred: get rid of CONFIG_DEBUG_CREDENTIALS	2023-12-15 14:19:48 -08:00
delayacct.c	delayacct: track delays from IRQ/SOFTIRQ	2023-04-18 16:39:34 -07:00
dma.c
exec_domain.c
exit.c	cred: get rid of CONFIG_DEBUG_CREDENTIALS	2023-12-15 14:19:48 -08:00
exit.h	exit: add internal include file with helpers	2023-09-21 12:03:50 -06:00
extable.c
fail_function.c	kernel/fail_function: fix memory leak with using debugfs_lookup()	2023-02-08 13:36:22 +01:00
fork.c	As usual, lots of singleton and doubleton patches all over the tree and	2023-11-02 20:53:31 -10:00
freezer.c	freezer,sched: Do not restore saved_state of a thawed task	2023-11-29 15:43:48 +01:00
gen_kheaders.sh	Revert "kheaders: substituting --sort in archive creation"	2023-05-28 16:20:21 +09:00
groups.c	groups: Convert group_info.usage to refcount_t	2023-09-29 11:28:39 -07:00
hung_task.c	kernel/hung_task.c: set some hung_task.c variables storage-class-specifier to static	2023-04-08 13:45:37 -07:00
iomem.c	kernel/iomem.c: remove __weak ioremap_cache helper	2023-08-21 13:37:28 -07:00
irq_work.c	trace: Add trace_ipi_send_cpu()	2023-03-24 11:01:29 +01:00
jump_label.c	jump_label: Prevent key->enabled int overflow	2022-12-01 15:53:05 -08:00
kallsyms_internal.h	kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[]	2022-11-12 18:47:36 -08:00
kallsyms_selftest.c	Modules changes for v6.6-rc1	2023-08-29 17:32:32 -07:00
kallsyms_selftest.h	kallsyms: Add self-test facility	2022-11-15 00:42:02 -08:00
kallsyms.c	kallsyms: Change func signature for cleanup_symbol_name()	2023-08-25 15:00:36 -07:00
kcmp.c	file: convert to SLAB_TYPESAFE_BY_RCU	2023-10-19 11:02:48 +02:00
Kconfig.freezer
Kconfig.hz
Kconfig.kexec	kexec: select CRYPTO from KEXEC_FILE instead of depending on it	2023-12-20 13:46:19 -08:00
Kconfig.locks
Kconfig.preempt
kcov.c	kcov: add prototypes for helper functions	2023-06-09 17:44:17 -07:00
kexec_core.c	kexec: do syscore_shutdown() in kernel_kexec	2024-01-31 16:21:02 -08:00
kexec_elf.c
kexec_file.c	integrity-v6.6	2023-08-30 09:16:56 -07:00
kexec_internal.h
kexec.c	kernel: kexec: copy user-array safely	2023-10-09 16:59:47 +10:00
kheaders.c	kheaders: Use array declaration instead of char	2023-03-24 20:10:59 -07:00
kprobes.c	kprobes: consistent rcu api usage for kretprobe holder	2023-12-01 14:53:55 +09:00
ksyms_common.c	kallsyms: make kallsyms_show_value() as generic function	2023-06-08 12:27:20 -07:00
ksysfs.c	crash: hotplug support for kexec_load()	2023-08-24 16:25:14 -07:00
kthread.c	As usual, lots of singleton and doubleton patches all over the tree and	2023-11-02 20:53:31 -10:00
latencytop.c
Makefile	v6.5-rc1-modules-next	2023-06-28 15:51:08 -07:00
module_signature.c
notifier.c	notifiers: add tracepoints to the notifiers infrastructure	2023-04-08 13:45:38 -07:00
nsproxy.c	nsproxy: Convert nsproxy.count to refcount_t	2023-08-21 11:29:12 -07:00
padata.c	padata: Fix refcnt handling in padata_free_shell()	2023-10-27 18:04:24 +08:00
panic.c	panic: use atomic_try_cmpxchg in panic() and nmi_panic()	2023-10-04 10:41:56 -07:00
params.c	kernel: params: Remove unnecessary ‘0’ values from err	2023-07-10 12:47:01 -07:00
pid_namespace.c	pid: pid_ns_ctl_handler: remove useless comment	2023-10-04 10:41:57 -07:00
pid_sysctl.h	memfd: replace ratcheting feature from vm.memfd_noexec with hierarchy	2023-08-21 13:37:59 -07:00
pid.c	pidfd: prevent a kernel-doc warning	2023-09-19 13:21:33 -07:00
profile.c
ptrace.c	mm: make __access_remote_vm() static	2023-10-18 14:34:15 -07:00
range.c
reboot.c	kernel/reboot: Add device to sys_off_handler	2023-07-28 11:33:09 +01:00
regset.c
relay.c	kernel: relay: remove unnecessary NULL values from relay_open_buf	2023-08-18 10:18:55 -07:00
resource_kunit.c
resource.c	kernel/resource: Increment by align value in get_free_mem_region()	2023-12-04 17:19:03 -08:00
rseq.c	rseq: Extend struct rseq with per-memory-map concurrency ID	2022-12-27 12:52:12 +01:00
scftorture.c	scftorture: Pause testing after memory-allocation failure	2023-07-14 15:02:57 -07:00
scs.c	scs: add support for dynamic shadow call stacks	2022-11-09 18:06:35 +00:00
seccomp.c	seccomp: Add missing kerndoc notations	2023-08-17 12:32:15 -07:00
signal.c	As usual, lots of singleton and doubleton patches all over the tree and	2023-11-02 20:53:31 -10:00
smp.c	CSD lock commits for v6.7	2023-10-30 17:56:53 -10:00
smpboot.c	kthread: add kthread_stop_put	2023-10-04 10:41:57 -07:00
smpboot.h
softirq.c	sched/core: introduce sched_core_idle_cpu()	2023-07-13 15:21:50 +02:00
stackleak.c	stackleak: allow to specify arch specific stackleak poison function	2023-04-20 11:36:35 +02:00
stacktrace.c	stacktrace: Export stack_trace_save_tsk	2023-09-11 23:59:47 -04:00
static_call_inline.c
static_call.c
stop_machine.c
sys_ni.c	posix-timers: Get rid of [COMPAT_]SYS_NI() uses	2023-12-20 21:30:27 -08:00
sys.c	getrusage: use sig->stats_lock rather than lock_task_sighand()	2024-02-23 09:51:45 +01:00
sysctl-test.c
sysctl.c	asm-generic updates for v6.7	2023-11-01 15:28:33 -10:00
task_work.c	task_work: add kerneldoc annotation for 'data' argument	2023-09-19 13:21:32 -07:00
taskstats.c	taskstats: fill_stats_for_tgid: use for_each_thread()	2023-10-04 10:41:57 -07:00
torture.c	torture: Print out torture module parameters	2023-09-24 17:24:01 +02:00
tracepoint.c	tracepoint: Allow livepatch module add trace event	2023-02-18 14:34:36 -05:00
tsacct.c
ucount.c	sysctl: Add size to register_sysctl	2023-08-15 15:26:17 -07:00
uid16.c
uid16.h
umh.c	sysctl: fix unused proc_cap_handler() function warning	2023-06-29 15:19:43 -07:00
up.c	smp: Change function signatures to use call_single_data_t	2023-09-13 14:59:24 +02:00
user_namespace.c	As usual, lots of singleton and doubleton patches all over the tree and	2023-11-02 20:53:31 -10:00
user-return-notifier.c
user.c	binfmt_misc: enable sandboxed mounts	2023-10-11 08:46:01 -07:00
usermode_driver.c
utsname_sysctl.c	utsname: simplify one-level sysctl registration for uts_kern_table	2023-04-13 11:49:35 -07:00
utsname.c
vhost_task.c	vhost: Fix worker hangs due to missed wake up calls	2023-06-08 15:43:09 -04:00
watch_queue.c	kernel: watch_queue: copy user-array safely	2023-10-09 16:59:48 +10:00
watchdog_buddy.c	watchdog/hardlockup: move SMP barriers from common code to buddy code	2023-06-19 16:25:28 -07:00
watchdog_perf.c	watchdog/perf: add a weak function for an arch to detect if perf can use NMIs	2023-06-09 17:44:21 -07:00
watchdog.c	watchdog: move softlockup_panic back to early_param	2023-11-01 12:10:02 -07:00
workqueue_internal.h	workqueue: Drop the special locking rule for worker->flags and worker_pool->flags	2023-08-07 15:57:22 -10:00
workqueue.c	workqueue: Don't call cpumask_test_cpu() with -1 CPU in wq_update_node_max_active()	2024-03-26 18:17:58 -04:00