On Sat, 15 Feb 2025 11:21:53 -0500 Steven Rostedt <[email protected]> wrote:
> On Sun, 16 Feb 2025 00:37:02 +0900 > Masami Hiramatsu (Google) <[email protected]> wrote: > > > My concern is related to the fixes policy. If this is a "fix", we will > > backport the new "disables mmap on persistent ring buffer" limitation > > to the stable kernel (that was not documented previously.) > > > > However, from the user point of view, "mmap() ring buffers" is already > > supported (although it did not work on stable kernel for now). Thus I think > > the "Fix" is expected as "fixing mmap() persistent ring buffer". > > This only disables mmapping of the persistent ring buffer. Other ring > buffers can be mapped. We never supported mmapping the persistent ring > buffer. Even in stable kernels, if you mmap it, it will crash just like > it does now. Thus, this doesn't cause any regressions. It's a fix even > for stable kernels. > > Or did the virt_to_page() change recently where that wasn't the case? > Although the fixes tag is wrong. As the persistent ring buffer didn't even exist then. It should be: Fixes: 9b7bdf6f6ece6 ("tracing: Have trace_printk not use binary prints if boot buffer") As that's what added the BOOT flag and is in the same kernel version that added the persistent ring buffer. -- Steve
