Re: [PATCH] ring-buffer: Fix reader page read offset for remote buffers
From: Keir Fraser <hidden>
Date: 2026-07-29 13:43:09
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On Wed, Jul 29, 2026 at 02:36:09PM +0100, Vincent Donnefort wrote:
A page swapped in by __rb_get_reader_page_from_remote() retains its
stale read offset, causing subsequent reads to skip events or read
past valid data. Fix it.
Fixes: fbd1743ecba1 ("ring-buffer: Add non-consuming read for ring-buffer remotes")
Signed-off-by: Vincent Donnefort <redacted>Reviewed-by: Keir Fraser <redacted> Tested-by: Keir Fraser <redacted>
quoted hunk ↗ jump to hunk
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 804ccae694d2..78d3875a47a5 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c@@ -5783,6 +5783,7 @@ __rb_get_reader_page_from_remote(struct ring_buffer_per_cpu *cpu_buffer) cpu_buffer->head_page = new_head; cpu_buffer->reader_page = new_reader; + cpu_buffer->reader_page->read = 0; cpu_buffer->pages = &new_head->list; cpu_buffer->read_stamp = new_reader->page->time_stamp; cpu_buffer->lost_events = cpu_buffer->meta_page->reader.lost_events;base-commit: f5098b6bae761e346ebcd9da7f95622c04733cff -- 2.55.0.487.gaf234c4eb3-goog