| Message ID | 1353559527-31818-1-git-send-email-herton.krzesinski@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index f765465..db6dff1 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1567,6 +1567,10 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, put_online_cpus(); } else { + /* Make sure this CPU has been intitialized */ + if (!cpumask_test_cpu(cpu_id, buffer->cpumask)) + goto out; + cpu_buffer = buffer->buffers[cpu_id]; if (nr_pages == cpu_buffer->nr_pages)
This is a note to let you know that I have just added a patch titled ring-buffer: Check for uninitialized cpu buffer before to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.yuz tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ From 6e3a3172e7808e9a0f43ef0d0f2383a085022546 Mon Sep 17 00:00:00 2001 From: Vaibhav Nagarnaik <vnagarnaik@google.com> Date: Wed, 10 Oct 2012 16:40:27 -0700 Subject: [PATCH] ring-buffer: Check for uninitialized cpu buffer before resizing commit 8e49f418c9632790bf456634742d34d97120a784 upstream. With a system where, num_present_cpus < num_possible_cpus, even if all CPUs are online, non-present CPUs don't have per_cpu buffers allocated. If per_cpu/<cpu>/buffer_size_kb is modified for such a CPU, it can cause a panic due to NULL dereference in ring_buffer_resize(). To fix this, resize operation is allowed only if the per-cpu buffer has been initialized. Link: http://lkml.kernel.org/r/1349912427-6486-1-git-send-email-vnagarnaik@google.com Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- kernel/trace/ring_buffer.c | 4 ++++ 1 file changed, 4 insertions(+) -- 1.7.9.5