ring-buffer: Fix ring_buffer_read_page() copying only one event per page

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Commit 8928e4a3be ("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: 8928e4a3be ("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>

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David Carlier 2026-06-16 18:55:38 +01:00 • committed by Steven Rostedt

parent a20b08de86

commit af05b4e062

1 changed files with 1 additions and 1 deletions

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kernel/trace/ring_buffer.c

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