--- /dev/null
+From e2bcb65782f91390952e849e21b82ed7cb05697f Mon Sep 17 00:00:00 2001
+From: Olivier Moysan <olivier.moysan@st.com>
+Date: Fri, 17 Apr 2020 16:21:22 +0200
+Subject: ASoC: stm32: sai: fix sai probe
+
+From: Olivier Moysan <olivier.moysan@st.com>
+
+commit e2bcb65782f91390952e849e21b82ed7cb05697f upstream.
+
+pcm config must be set before snd_dmaengine_pcm_register() call.
+
+Fixes: 0d6defc7e0e4 ("ASoC: stm32: sai: manage rebind issue")
+
+Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
+Link: https://lore.kernel.org/r/20200417142122.10212-1-olivier.moysan@st.com
+Signed-off-by: Mark Brown <broonie@kernel.org>
+Cc: Guenter Roeck <linux@roeck-us.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ sound/soc/stm/stm32_sai_sub.c | 12 +++++-------
+ 1 file changed, 5 insertions(+), 7 deletions(-)
+
+--- a/sound/soc/stm/stm32_sai_sub.c
++++ b/sound/soc/stm/stm32_sai_sub.c
+@@ -1543,6 +1543,9 @@ static int stm32_sai_sub_probe(struct pl
+ return ret;
+ }
+
++ if (STM_SAI_PROTOCOL_IS_SPDIF(sai))
++ conf = &stm32_sai_pcm_config_spdif;
++
+ ret = snd_dmaengine_pcm_register(&pdev->dev, conf, 0);
+ if (ret) {
+ dev_err(&pdev->dev, "Could not register pcm dma\n");
+@@ -1551,15 +1554,10 @@ static int stm32_sai_sub_probe(struct pl
+
+ ret = snd_soc_register_component(&pdev->dev, &stm32_component,
+ &sai->cpu_dai_drv, 1);
+- if (ret) {
++ if (ret)
+ snd_dmaengine_pcm_unregister(&pdev->dev);
+- return ret;
+- }
+-
+- if (STM_SAI_PROTOCOL_IS_SPDIF(sai))
+- conf = &stm32_sai_pcm_config_spdif;
+
+- return 0;
++ return ret;
+ }
+
+ static int stm32_sai_sub_remove(struct platform_device *pdev)
--- /dev/null
+From ab6f762f0f53162d41497708b33c9a3236d3609e Mon Sep 17 00:00:00 2001
+From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Date: Tue, 3 Mar 2020 20:30:02 +0900
+Subject: printk: queue wake_up_klogd irq_work only if per-CPU areas are ready
+
+From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+
+commit ab6f762f0f53162d41497708b33c9a3236d3609e upstream.
+
+printk_deferred(), similarly to printk_safe/printk_nmi, does not
+immediately attempt to print a new message on the consoles, avoiding
+calls into non-reentrant kernel paths, e.g. scheduler or timekeeping,
+which potentially can deadlock the system.
+
+Those printk() flavors, instead, rely on per-CPU flush irq_work to print
+messages from safer contexts. For same reasons (recursive scheduler or
+timekeeping calls) printk() uses per-CPU irq_work in order to wake up
+user space syslog/kmsg readers.
+
+However, only printk_safe/printk_nmi do make sure that per-CPU areas
+have been initialised and that it's safe to modify per-CPU irq_work.
+This means that, for instance, should printk_deferred() be invoked "too
+early", that is before per-CPU areas are initialised, printk_deferred()
+will perform illegal per-CPU access.
+
+Lech Perczak [0] reports that after commit 1b710b1b10ef ("char/random:
+silence a lockdep splat with printk()") user-space syslog/kmsg readers
+are not able to read new kernel messages.
+
+The reason is printk_deferred() being called too early (as was pointed
+out by Petr and John).
+
+Fix printk_deferred() and do not queue per-CPU irq_work before per-CPU
+areas are initialized.
+
+Link: https://lore.kernel.org/lkml/aa0732c6-5c4e-8a8b-a1c1-75ebe3dca05b@camlintechnologies.com/
+Reported-by: Lech Perczak <l.perczak@camlintechnologies.com>
+Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Tested-by: Jann Horn <jannh@google.com>
+Reviewed-by: Petr Mladek <pmladek@suse.com>
+Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Cc: Theodore Ts'o <tytso@mit.edu>
+Cc: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Cc: Guenter Roeck <linux@roeck-us.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ include/linux/printk.h | 5 -----
+ init/main.c | 1 -
+ kernel/printk/internal.h | 5 +++++
+ kernel/printk/printk.c | 34 ++++++++++++++++++++++++++++++++++
+ kernel/printk/printk_safe.c | 11 +----------
+ 5 files changed, 40 insertions(+), 16 deletions(-)
+
+--- a/include/linux/printk.h
++++ b/include/linux/printk.h
+@@ -202,7 +202,6 @@ __printf(1, 2) void dump_stack_set_arch_
+ void dump_stack_print_info(const char *log_lvl);
+ void show_regs_print_info(const char *log_lvl);
+ extern asmlinkage void dump_stack(void) __cold;
+-extern void printk_safe_init(void);
+ extern void printk_safe_flush(void);
+ extern void printk_safe_flush_on_panic(void);
+ #else
+@@ -269,10 +268,6 @@ static inline void dump_stack(void)
+ {
+ }
+
+-static inline void printk_safe_init(void)
+-{
+-}
+-
+ static inline void printk_safe_flush(void)
+ {
+ }
+--- a/init/main.c
++++ b/init/main.c
+@@ -907,7 +907,6 @@ asmlinkage __visible void __init start_k
+ boot_init_stack_canary();
+
+ time_init();
+- printk_safe_init();
+ perf_event_init();
+ profile_init();
+ call_function_init();
+--- a/kernel/printk/internal.h
++++ b/kernel/printk/internal.h
+@@ -23,6 +23,9 @@ __printf(1, 0) int vprintk_func(const ch
+ void __printk_safe_enter(void);
+ void __printk_safe_exit(void);
+
++void printk_safe_init(void);
++bool printk_percpu_data_ready(void);
++
+ #define printk_safe_enter_irqsave(flags) \
+ do { \
+ local_irq_save(flags); \
+@@ -64,4 +67,6 @@ __printf(1, 0) int vprintk_func(const ch
+ #define printk_safe_enter_irq() local_irq_disable()
+ #define printk_safe_exit_irq() local_irq_enable()
+
++static inline void printk_safe_init(void) { }
++static inline bool printk_percpu_data_ready(void) { return false; }
+ #endif /* CONFIG_PRINTK */
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -460,6 +460,18 @@ static char __log_buf[__LOG_BUF_LEN] __a
+ static char *log_buf = __log_buf;
+ static u32 log_buf_len = __LOG_BUF_LEN;
+
++/*
++ * We cannot access per-CPU data (e.g. per-CPU flush irq_work) before
++ * per_cpu_areas are initialised. This variable is set to true when
++ * it's safe to access per-CPU data.
++ */
++static bool __printk_percpu_data_ready __read_mostly;
++
++bool printk_percpu_data_ready(void)
++{
++ return __printk_percpu_data_ready;
++}
++
+ /* Return log buffer address */
+ char *log_buf_addr_get(void)
+ {
+@@ -1146,12 +1158,28 @@ static void __init log_buf_add_cpu(void)
+ static inline void log_buf_add_cpu(void) {}
+ #endif /* CONFIG_SMP */
+
++static void __init set_percpu_data_ready(void)
++{
++ printk_safe_init();
++ /* Make sure we set this flag only after printk_safe() init is done */
++ barrier();
++ __printk_percpu_data_ready = true;
++}
++
+ void __init setup_log_buf(int early)
+ {
+ unsigned long flags;
+ char *new_log_buf;
+ unsigned int free;
+
++ /*
++ * Some archs call setup_log_buf() multiple times - first is very
++ * early, e.g. from setup_arch(), and second - when percpu_areas
++ * are initialised.
++ */
++ if (!early)
++ set_percpu_data_ready();
++
+ if (log_buf != __log_buf)
+ return;
+
+@@ -2966,6 +2994,9 @@ static DEFINE_PER_CPU(struct irq_work, w
+
+ void wake_up_klogd(void)
+ {
++ if (!printk_percpu_data_ready())
++ return;
++
+ preempt_disable();
+ if (waitqueue_active(&log_wait)) {
+ this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
+@@ -2976,6 +3007,9 @@ void wake_up_klogd(void)
+
+ void defer_console_output(void)
+ {
++ if (!printk_percpu_data_ready())
++ return;
++
+ preempt_disable();
+ __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
+ irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
+--- a/kernel/printk/printk_safe.c
++++ b/kernel/printk/printk_safe.c
+@@ -27,7 +27,6 @@
+ * There are situations when we want to make sure that all buffers
+ * were handled or when IRQs are blocked.
+ */
+-static int printk_safe_irq_ready __read_mostly;
+
+ #define SAFE_LOG_BUF_LEN ((1 << CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT) - \
+ sizeof(atomic_t) - \
+@@ -51,7 +50,7 @@ static DEFINE_PER_CPU(struct printk_safe
+ /* Get flushed in a more safe context. */
+ static void queue_flush_work(struct printk_safe_seq_buf *s)
+ {
+- if (printk_safe_irq_ready)
++ if (printk_percpu_data_ready())
+ irq_work_queue(&s->work);
+ }
+
+@@ -402,14 +401,6 @@ void __init printk_safe_init(void)
+ #endif
+ }
+
+- /*
+- * In the highly unlikely event that a NMI were to trigger at
+- * this moment. Make sure IRQ work is set up before this
+- * variable is set.
+- */
+- barrier();
+- printk_safe_irq_ready = 1;
+-
+ /* Flush pending messages that did not have scheduled IRQ works. */
+ printk_safe_flush();
+ }
projects / thirdparty / kernel / stable-queue.git / commitdiff
