diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 43 |
1 files changed, 30 insertions, 13 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 5979327254f9..e2de5b448c91 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -441,6 +441,7 @@ enum { struct ring_buffer_per_cpu { int cpu; atomic_t record_disabled; + atomic_t resize_disabled; struct trace_buffer *buffer; raw_spinlock_t reader_lock; /* serialize readers */ arch_spinlock_t lock; @@ -484,7 +485,6 @@ struct trace_buffer { unsigned flags; int cpus; atomic_t record_disabled; - atomic_t resize_disabled; cpumask_var_t cpumask; struct lock_class_key *reader_lock_key; @@ -1740,18 +1740,24 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, size = nr_pages * BUF_PAGE_SIZE; - /* - * Don't succeed if resizing is disabled, as a reader might be - * manipulating the ring buffer and is expecting a sane state while - * this is true. - */ - if (atomic_read(&buffer->resize_disabled)) - return -EBUSY; - /* prevent another thread from changing buffer sizes */ mutex_lock(&buffer->mutex); + if (cpu_id == RING_BUFFER_ALL_CPUS) { + /* + * Don't succeed if resizing is disabled, as a reader might be + * manipulating the ring buffer and is expecting a sane state while + * this is true. + */ + for_each_buffer_cpu(buffer, cpu) { + cpu_buffer = buffer->buffers[cpu]; + if (atomic_read(&cpu_buffer->resize_disabled)) { + err = -EBUSY; + goto out_err_unlock; + } + } + /* calculate the pages to update */ for_each_buffer_cpu(buffer, cpu) { cpu_buffer = buffer->buffers[cpu]; @@ -1819,6 +1825,16 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, if (nr_pages == cpu_buffer->nr_pages) goto out; + /* + * Don't succeed if resizing is disabled, as a reader might be + * manipulating the ring buffer and is expecting a sane state while + * this is true. + */ + if (atomic_read(&cpu_buffer->resize_disabled)) { + err = -EBUSY; + goto out_err_unlock; + } + cpu_buffer->nr_pages_to_update = nr_pages - cpu_buffer->nr_pages; @@ -1888,6 +1904,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, free_buffer_page(bpage); } } + out_err_unlock: mutex_unlock(&buffer->mutex); return err; } @@ -4294,7 +4311,7 @@ ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags) iter->cpu_buffer = cpu_buffer; - atomic_inc(&buffer->resize_disabled); + atomic_inc(&cpu_buffer->resize_disabled); atomic_inc(&cpu_buffer->record_disabled); return iter; @@ -4369,7 +4386,7 @@ ring_buffer_read_finish(struct ring_buffer_iter *iter) raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); atomic_dec(&cpu_buffer->record_disabled); - atomic_dec(&cpu_buffer->buffer->resize_disabled); + atomic_dec(&cpu_buffer->resize_disabled); kfree(iter->event); kfree(iter); } @@ -4474,7 +4491,7 @@ void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu) if (!cpumask_test_cpu(cpu, buffer->cpumask)) return; - atomic_inc(&buffer->resize_disabled); + atomic_inc(&cpu_buffer->resize_disabled); atomic_inc(&cpu_buffer->record_disabled); /* Make sure all commits have finished */ @@ -4495,7 +4512,7 @@ void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu) raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); atomic_dec(&cpu_buffer->record_disabled); - atomic_dec(&buffer->resize_disabled); + atomic_dec(&cpu_buffer->resize_disabled); } EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu); |