diff options
| author | David Carlier <devnexen@gmail.com> | 2026-06-16 18:55:38 +0100 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2026-07-07 10:38:03 -0400 |
| commit | af05b4e06279bbe34f8044b1e82f0725b5da91b7 (patch) | |
| tree | d504f21b779c3a67111ed0026319a1a79cec1fa1 /kernel/trace | |
| parent | a20b08de862c2983eac183b7560ad678acb58608 (diff) | |
ring-buffer: Fix ring_buffer_read_page() copying only one event per page
Commit 8928e4a3be34 ("ring-buffer: Show persistent buffer dropped events
in trace_pipe file") split the "commit" variable in
ring_buffer_read_page() into "commit" (raw) and "size" (masked page
size), but the inner copy loop's terminator was changed to compare rpos
against "event_size" instead of "size".
rpos is the cumulative read offset within the page; event_size is the
length of the single event just copied. The loop thus breaks after the
first event, so only one event is copied per call. This regresses the
per-event memcpy path (partial reads, the active commit page, and
mapped/remote buffers) used by splice/trace_pipe_raw and mmap consumers
into a one-event-at-a-time read.
Compare rpos against the page size as the original code did.
Link: https://patch.msgid.link/20260616175538.111628-1-devnexen@gmail.com
Fixes: 8928e4a3be34 ("ring-buffer: Show persistent buffer dropped events in trace_pipe file")
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index d9af2bbaf9c0..12a83d9ffd0a 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7175,7 +7175,7 @@ int ring_buffer_read_page(struct trace_buffer *buffer, rpos = reader->read; pos += event_size; - if (rpos >= event_size) + if (rpos >= size) break; event = rb_reader_event(cpu_buffer); |