diff options
| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-04-24 15:52:10 +0900 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2026-04-24 15:34:39 -0400 |
| commit | 92d5a606721f759ebebf448b3bd2b7a781d50bd0 (patch) | |
| tree | 009c94ff1d7585306dadcf2e1256129b22d0e510 /kernel | |
| parent | 5335e318ad3cf12d905de27e3be4e7fd7b1c6746 (diff) | |
ring-buffer: Do not double count the reader_page
Since the cpu_buffer->reader_page is updated if there are unwound
pages. After that update, we should skip the page if it is the
original reader_page, because the original reader_page is already
checked.
Cc: stable@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ian Rogers <irogers@google.com>
Link: https://patch.msgid.link/177701353063.2223789.1471163147644103306.stgit@mhiramat.tok.corp.google.com
Fixes: ca296d32ece3 ("tracing: ring_buffer: Rewind persistent ring buffer on reboot")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index cef49f8871d2..5326924615a4 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1884,7 +1884,7 @@ static int rb_validate_buffer(struct buffer_data_page *dpage, int cpu) static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) { struct ring_buffer_cpu_meta *meta = cpu_buffer->ring_meta; - struct buffer_page *head_page, *orig_head; + struct buffer_page *head_page, *orig_head, *orig_reader; unsigned long entry_bytes = 0; unsigned long entries = 0; int ret; @@ -1895,16 +1895,17 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) return; orig_head = head_page = cpu_buffer->head_page; + orig_reader = cpu_buffer->reader_page; /* Do the reader page first */ - ret = rb_validate_buffer(cpu_buffer->reader_page->page, cpu_buffer->cpu); + ret = rb_validate_buffer(orig_reader->page, cpu_buffer->cpu); if (ret < 0) { pr_info("Ring buffer reader page is invalid\n"); goto invalid; } entries += ret; - entry_bytes += local_read(&cpu_buffer->reader_page->page->commit); - local_set(&cpu_buffer->reader_page->entries, ret); + entry_bytes += local_read(&orig_reader->page->commit); + local_set(&orig_reader->entries, ret); ts = head_page->page->time_stamp; @@ -2007,8 +2008,8 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) /* Iterate until finding the commit page */ for (i = 0; i < meta->nr_subbufs + 1; i++, rb_inc_page(&head_page)) { - /* Reader page has already been done */ - if (head_page == cpu_buffer->reader_page) + /* The original reader page has already been checked/counted. */ + if (head_page == orig_reader) continue; ret = rb_validate_buffer(head_page->page, cpu_buffer->cpu); |