diff options
| author | Vincent Donnefort <vdonnefort@google.com> | 2024-01-31 17:09:55 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-02-23 11:25:08 +0300 |
| commit | f5f6332f1870ea204a2cf42ec355705b56ada5ec (patch) | |
| tree | 231e0f10cdef3c34ed0cef7cf04ecde527d55101 | |
| parent | 22a77c0f5b8233237731df3288d067af51a2fd7b (diff) | |
| download | linux-f5f6332f1870ea204a2cf42ec355705b56ada5ec.tar.xz | |
ring-buffer: Clean ring_buffer_poll_wait() error return
commit 66bbea9ed6446b8471d365a22734dc00556c4785 upstream.
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 <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/trace/ring_buffer.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index f232cf56fa05..1ac6637895a4 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1091,7 +1091,7 @@ __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; |