diff options
| author | James Morris <james.l.morris@oracle.com> | 2017-11-29 12:47:41 +1100 |
|---|---|---|
| committer | James Morris <james.l.morris@oracle.com> | 2017-11-29 12:47:41 +1100 |
| commit | cf40a76e7d5874bb25f4404eecc58a2e033af885 (patch) | |
| tree | 8fd81cbea03c87b3d41d7ae5b1d11eadd35d6ef5 /kernel/printk/printk_safe.c | |
| parent | ab5348c9c23cd253f5902980d2d8fe067dc24c82 (diff) | |
| parent | 4fbd8d194f06c8a3fd2af1ce560ddb31f7ec8323 (diff) | |
Merge tag 'v4.15-rc1' into next-seccomp
Linux 4.15-rc1
Diffstat (limited to 'kernel/printk/printk_safe.c')
| -rw-r--r-- | kernel/printk/printk_safe.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index 3cdaeaef9ce1..3e3c2004bb23 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -39,7 +39,7 @@ * 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; +static int printk_safe_irq_ready __read_mostly; #define SAFE_LOG_BUF_LEN ((1 << CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT) - \ sizeof(atomic_t) - \ @@ -63,11 +63,8 @@ static DEFINE_PER_CPU(struct printk_safe_seq_buf, nmi_print_seq); /* Get flushed in a more safe context. */ static void queue_flush_work(struct printk_safe_seq_buf *s) { - if (printk_safe_irq_ready) { - /* Make sure that IRQ work is really initialized. */ - smp_rmb(); + if (printk_safe_irq_ready) irq_work_queue(&s->work); - } } /* @@ -75,7 +72,7 @@ static void queue_flush_work(struct printk_safe_seq_buf *s) * have dedicated buffers, because otherwise printk-safe preempted by * NMI-printk would have overwritten the NMI messages. * - * The messages are fushed from irq work (or from panic()), possibly, + * The messages are flushed from irq work (or from panic()), possibly, * from other CPU, concurrently with printk_safe_log_store(). Should this * happen, printk_safe_log_store() will notice the buffer->len mismatch * and repeat the write. @@ -398,8 +395,12 @@ void __init printk_safe_init(void) #endif } - /* Make sure that IRQ works are initialized before enabling. */ - smp_wmb(); + /* + * 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. */ |