On Wed, 18 Feb 2026 19:14:35 +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 invalidate all ring buffers. instead of discarding the entire ring 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, allowing usersto > recover data from the corrupted ring buffer. ... contain readable event data. Only discard the subbuffers that are found to be corrupted. > > Signed-off-by: Masami Hiramatsu (Google) <[email protected]> > --- > kernel/trace/ring_buffer.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c > index d2b69221a94c..0ae2a5ad8c3e 100644 > --- a/kernel/trace/ring_buffer.c > +++ b/kernel/trace/ring_buffer.c > @@ -2045,17 +2045,19 @@ 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); > - goto invalid; > - } > - > - /* If the buffer has content, update pages_touched */ > - if (ret) > - local_inc(&cpu_buffer->pages_touched); > - > - entries += ret; > - entry_bytes += local_read(&head_page->page->commit); > - local_set(&cpu_buffer->head_page->entries, ret); > + /* Instead of invalidate whole ring buffer, just clear > this subbuffer. */ > + local_set(&head_page->entries, 0); > + local_set(&head_page->page->commit, 0); > + /* TODO: commit an event to mark this is broken. */ Here's how to fix the TODO: local_set(&head_page->page->commit, RB_MISSED_EVENTS); -- Steve > + } else { > + /* If the buffer has content, update pages_touched */ > + if (ret) > + local_inc(&cpu_buffer->pages_touched); > > + entries += ret; > + entry_bytes += local_read(&head_page->page->commit); > + local_set(&cpu_buffer->head_page->entries, ret); > + } > if (head_page == cpu_buffer->commit_page) > break; > }
