From: Vincent Donnefort Date: Wed, 31 Jan 2024 14:09:55 +0000 (+0000) Subject: ring-buffer: Clean ring_buffer_poll_wait() error return X-Git-Tag: v6.8-rc3~11^2~12 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=66bbea9ed6446b8471d365a22734dc00556c4785;p=thirdparty%2Fkernel%2Flinux.git ring-buffer: Clean ring_buffer_poll_wait() error return 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. Link: https://lore.kernel.org/linux-trace-kernel/20240131140955.3322792-1-vdonnefort@google.com Cc: stable@vger.kernel.org Fixes: 6721cb6002262 ("ring-buffer: Do not poll non allocated cpu buffers") Signed-off-by: Vincent Donnefort Signed-off-by: Steven Rostedt (Google) --- diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 13aaf5e85b811..fd4bfe3ecf014 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;