[v2] ring-buffer: use READ_ONCE() to read cpu_buffer->commit_page in concurrent environment
Message ID | tencent_DFF7D3561A0686B5E8FC079150A02505180A@qq.com |
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State | New |
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Series |
[v2] ring-buffer: use READ_ONCE() to read cpu_buffer->commit_page in concurrent environment
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Commit Message
linke li
March 2, 2024, 4:42 a.m. UTC
In function ring_buffer_iter_empty(), cpu_buffer->commit_page is read
while other threads may change it. It may cause the time_stamp that read
in the next line come from a different page. Use READ_ONCE() to avoid
having to reason about compiler optimizations now and in future.
Signed-off-by: linke li <lilinke99@qq.com>
---
v1 -> v2: only add READ_ONCE() to read cpu_buffer->commit_page, make change log clear
kernel/trace/ring_buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 0699027b4f4c..c7203a436d3c 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -4337,7 +4337,7 @@ int ring_buffer_iter_empty(struct ring_buffer_iter *iter) cpu_buffer = iter->cpu_buffer; reader = cpu_buffer->reader_page; head_page = cpu_buffer->head_page; - commit_page = cpu_buffer->commit_page; + commit_page = READ_ONCE(cpu_buffer->commit_page); commit_ts = commit_page->page->time_stamp; /*