Messages in this thread Patch in this message | | | Date | Wed, 31 Jan 2024 14:09:55 +0000 | Subject | [PATCH] ring-buffer: Clean ring_buffer_poll_wait() error return | From | Vincent Donnefort <> |
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The return type for ring_buffer_poll_wait() is __poll_t. This is behind the scenes an unsigned where we can set event bits. In case of a non-allocated CPU, we do return instead -EINVAL (0xffffffea). Lucky us, this ends up setting few error bits (EPOLLERR | EPOLLHUP | EPOLLNVAL), so user-space at least is aware something went wrong.
Nonetheless, this is an incorrect code. Replace that -EINVAL with a proper EPOLLERR to clean that output. As this doesn't change the behaviour, there's no need to treat this change as a bug fix.
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 13aaf5e85b81..fd4bfe3ecf01 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -944,7 +944,7 @@ __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, full = 0; } else { if (!cpumask_test_cpu(cpu, buffer->cpumask)) - return -EINVAL; + return EPOLLERR; cpu_buffer = buffer->buffers[cpu]; work = &cpu_buffer->irq_work; base-commit: 29142dc92c37d3259a33aef15b03e6ee25b0d188 -- 2.43.0.429.g432eaa2c6b-goog
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