On Tue, 24 Feb 2026 15:52:57 +0900 "Masami Hiramatsu (Google)" <[email protected]> wrote:
> From: Masami Hiramatsu (Google) <[email protected]> > > Skip invalid sub-buffers when validating the persistent ring buffer > instead of discarding the entire ring buffer. Also, mark there are > missed events on the discarded buffer. > > If the cache data in memory fails to be synchronized during a reboot, > the persistent ring buffer may become partially corrupted, but other > sub-buffers may still contain readable event data. Only discard the > subbuffersa that ar found to be corrupted. > > Signed-off-by: Masami Hiramatsu (Google) <[email protected]> > --- > Changes in v3: > - Record missed data event on commit. > --- > kernel/trace/ring_buffer.c | 21 +++++++++++---------- > 1 file changed, 11 insertions(+), 10 deletions(-) > > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c > index 67bc652ba02a..72f82e2e6740 100644 > --- a/kernel/trace/ring_buffer.c > +++ b/kernel/trace/ring_buffer.c > @@ -2058,17 +2058,18 @@ static void rb_meta_validate_events(struct > ring_buffer_per_cpu *cpu_buffer) > if (ret < 0) { > pr_info("Ring buffer meta [%d] invalid buffer page\n", > cpu_buffer->cpu); This pr_info() should be removed too, because multiple pages can be discarded. Thanks, > - goto invalid; > - } > - > - /* If the buffer has content, update pages_touched */ > - if (ret) > - local_inc(&cpu_buffer->pages_touched); > - > - entries += ret; > - entry_bytes += rb_page_size(head_page); > - local_set(&cpu_buffer->head_page->entries, ret); > + /* Instead of discard whole ring buffer, discard only > this sub-buffer. */ > + local_set(&head_page->entries, 0); > + local_set(&head_page->page->commit, RB_MISSED_EVENTS); > + } else { > + /* If the buffer has content, update pages_touched */ > + if (ret) > + local_inc(&cpu_buffer->pages_touched); > > + entries += ret; > + entry_bytes += rb_page_size(head_page); > + local_set(&cpu_buffer->head_page->entries, ret); > + } > if (head_page == cpu_buffer->commit_page) > break; > } > -- Masami Hiramatsu (Google) <[email protected]>
