diff options
| -rw-r--r-- | kernel/printk/printk.c | 90 | ||||
| -rw-r--r-- | kernel/printk/printk_ringbuffer.c | 17 | ||||
| -rw-r--r-- | lib/vsprintf.c | 11 |
3 files changed, 60 insertions, 58 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 6d3d18a50da7..6c8bacb173b7 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1085,9 +1085,9 @@ static void __init log_buf_add_cpu(void) if (num_possible_cpus() == 1) return; - cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN; + cpu_extra = num_possible_cpus() * __LOG_CPU_MAX_BUF_LEN; - /* by default this will only continue through for large > 64 CPUs */ + /* by default this will only continue through for more than 16 CPUs */ if (cpu_extra <= __LOG_BUF_LEN / 2) return; @@ -4424,36 +4424,51 @@ void __init console_init(void) * be a brief interval in which no messages are logged to the console, which * makes it difficult to diagnose problems that occur during this time. * - * To mitigate this problem somewhat, only unregister consoles whose memory - * intersects with the init section. Note that all other boot consoles will - * get unregistered when the real preferred console is registered. + * If a real console has already registered, remove all remaining boot consoles. + * Otherwise, mitigate the no-console interval by removing only boot consoles + * whose memory intersects with the init section. */ static int __init printk_late_init(void) { + bool have_real_console = false; struct hlist_node *tmp; struct console *con; int ret; console_list_lock(); + for_each_console(con) { + if (!(con->flags & CON_BOOT)) { + have_real_console = true; + break; + } + } + hlist_for_each_entry_safe(con, tmp, &console_list, node) { if (!(con->flags & CON_BOOT)) continue; - /* Check addresses that might be used for enabled consoles. */ - if (init_section_intersects(con, sizeof(*con)) || - init_section_contains(con->write, 0) || - init_section_contains(con->read, 0) || - init_section_contains(con->device, 0) || - init_section_contains(con->unblank, 0) || - init_section_contains(con->data, 0)) { + /* + * Keep the boot console when requested or as a fallback + * unless it is using an init section. + */ + if (keep_bootcon || !have_real_console) { + if (!init_section_intersects(con, sizeof(*con)) && + !init_section_contains(con->write, 0) && + !init_section_contains(con->read, 0) && + !init_section_contains(con->device, 0) && + !init_section_contains(con->unblank, 0) && + !init_section_contains(con->data, 0)) + continue; + /* * Please, consider moving the reported consoles out * of the init section. */ pr_warn("bootconsole [%s%d] uses init memory and must be disabled even before the real one is ready\n", con->name, con->index); - unregister_console_locked(con); } + + unregister_console_locked(con); } console_list_unlock(); @@ -4593,31 +4608,26 @@ bool pr_flush(int timeout_ms, bool reset_on_progress) /* * Delayed printk version, for scheduler-internal messages: */ -#define PRINTK_PENDING_WAKEUP 0x01 -#define PRINTK_PENDING_OUTPUT 0x02 - -static DEFINE_PER_CPU(int, printk_pending); +#define PRINTK_PENDING_OUTPUT 0x01 -static void wake_up_klogd_work_func(struct irq_work *irq_work) +static void pending_wake_fn(struct irq_work *irq_work) { - int pending = this_cpu_xchg(printk_pending, 0); + wake_up_interruptible(&log_wait); +} - if (pending & PRINTK_PENDING_OUTPUT) { - if (force_legacy_kthread()) { - if (printk_legacy_kthread) - wake_up_interruptible(&legacy_wait); - } else { - if (console_trylock()) - console_unlock(); - } +static void pending_output_fn(struct irq_work *irq_work) +{ + if (force_legacy_kthread()) { + if (printk_legacy_kthread) + wake_up_interruptible(&legacy_wait); + } else { + if (console_trylock()) + console_unlock(); } - - if (pending & PRINTK_PENDING_WAKEUP) - wake_up_interruptible(&log_wait); } -static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = - IRQ_WORK_INIT_LAZY(wake_up_klogd_work_func); +static struct irq_work pending_wakeup_work = IRQ_WORK_INIT_LAZY(pending_wake_fn); +static struct irq_work pending_output_work = IRQ_WORK_INIT_LAZY(pending_output_fn); static void __wake_up_klogd(int val) { @@ -4631,7 +4641,6 @@ static void __wake_up_klogd(int val) if (WARN_ON_ONCE(console_irqwork_blocked)) return; - preempt_disable(); /* * Guarantee any new records can be seen by tasks preparing to wait * before this context checks if the wait queue is empty. @@ -4643,12 +4652,11 @@ static void __wake_up_klogd(int val) * * This pairs with devkmsg_read:A and syslog_print:A. */ - if (wq_has_sleeper(&log_wait) || /* LMM(__wake_up_klogd:A) */ - (val & PRINTK_PENDING_OUTPUT)) { - this_cpu_or(printk_pending, val); - irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); - } - preempt_enable(); + if (wq_has_sleeper(&log_wait)) /* LMM(__wake_up_klogd:A) */ + irq_work_queue(&pending_wakeup_work); + + if (val & PRINTK_PENDING_OUTPUT) + irq_work_queue(&pending_output_work); } /** @@ -4663,7 +4671,7 @@ static void __wake_up_klogd(int val) */ void wake_up_klogd(void) { - __wake_up_klogd(PRINTK_PENDING_WAKEUP); + __wake_up_klogd(0); } /** @@ -4684,7 +4692,7 @@ void defer_console_output(void) * New messages may have been added directly to the ringbuffer * using vprintk_store(), so wake any waiters as well. */ - __wake_up_klogd(PRINTK_PENDING_WAKEUP | PRINTK_PENDING_OUTPUT); + __wake_up_klogd(PRINTK_PENDING_OUTPUT); } /** diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c index 85c0c854b3ce..d38e7c2f6887 100644 --- a/kernel/printk/printk_ringbuffer.c +++ b/kernel/printk/printk_ringbuffer.c @@ -439,13 +439,12 @@ static enum desc_state get_desc_state(unsigned long id, } /* - * Get a copy of a specified descriptor and return its queried state. If the - * descriptor is in an inconsistent state (miss or reserved), the caller can - * only expect the descriptor's @state_var field to be valid. + * Get the state of a specified descriptor. * - * The sequence number and caller_id can be optionally retrieved. Like all - * non-state_var data, they are only valid if the descriptor is in a - * consistent state. + * Optionally, a copy of the descriptor, sequence number and/or caller ID can + * be retrieved. However, (with the exception of @desc_out->state_var) all + * retrieved values are invalid if the descriptor is in an inconsistent state + * (miss or reserved). */ static enum desc_state desc_read(struct prb_desc_ring *desc_ring, unsigned long id, struct prb_desc *desc_out, @@ -1335,7 +1334,6 @@ static struct prb_desc *desc_reopen_last(struct prb_desc_ring *desc_ring, { unsigned long prev_state_val; enum desc_state d_state; - struct prb_desc desc; struct prb_desc *d; unsigned long id; u32 cid; @@ -1346,7 +1344,7 @@ static struct prb_desc *desc_reopen_last(struct prb_desc_ring *desc_ring, * To reduce unnecessarily reopening, first check if the descriptor * state and caller ID are correct. */ - d_state = desc_read(desc_ring, id, &desc, NULL, &cid); + d_state = desc_read(desc_ring, id, NULL, NULL, &cid); if (d_state != desc_committed || cid != caller_id) return NULL; @@ -2007,14 +2005,13 @@ u64 prb_first_seq(struct printk_ringbuffer *rb) { struct prb_desc_ring *desc_ring = &rb->desc_ring; enum desc_state d_state; - struct prb_desc desc; unsigned long id; u64 seq; for (;;) { id = atomic_long_read(&rb->desc_ring.tail_id); /* LMM(prb_first_seq:A) */ - d_state = desc_read(desc_ring, id, &desc, &seq, NULL); /* LMM(prb_first_seq:B) */ + d_state = desc_read(desc_ring, id, NULL, &seq, NULL); /* LMM(prb_first_seq:B) */ /* * This loop will not be infinite because the tail is diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 1d95ab9314bf..90d0a724eadd 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -762,9 +762,8 @@ static int fill_ptr_key(struct notifier_block *nb, unsigned long action, void *d { get_random_bytes(&ptr_key, sizeof(ptr_key)); - /* Pairs with smp_rmb() before reading ptr_key. */ - smp_wmb(); - WRITE_ONCE(filled_random_ptr_key, true); + /* Pairs with smp_load_acquire() before reading ptr_key. */ + smp_store_release(&filled_random_ptr_key, true); return NOTIFY_DONE; } @@ -781,12 +780,10 @@ static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out) { unsigned long hashval; - if (!READ_ONCE(filled_random_ptr_key)) + /* Pairs with smp_store_release() after writing ptr_key. */ + if (!smp_load_acquire(&filled_random_ptr_key)) return -EBUSY; - /* Pairs with smp_wmb() after writing ptr_key. */ - smp_rmb(); - #ifdef CONFIG_64BIT hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key); /* |