Re: [PATCH] mac80211: debugfs: bound queue state formatting to PAGE_SIZE

[Johannes Berg]

On Fri, 2026-04-17 at 15:46 +0800, Pengpeng Hou wrote:
> queues_read() formats all queue state lines into a fixed stack buffer
> that budgets only 20 bytes per queue and appends each line with
> sprintf().
> 
> The queue-stop reason bitmap is printed with %#.8lx, whose width is not
> capped on 64-bit builds, and the pending queue length field can add more
> digits still. The cumulative output can therefore run past the end of
> the fixed stack buffer.

I'd agree the code isn't optimal, but this simply isn't true.

> Format the output into a PAGE_SIZE heap buffer with scnprintf() and stop
> once the debugfs read buffer is full.

And the fix is just strange.

> Fixes: db2e6bd4e966 ("mac80211: add queue debugfs file")
> 
> Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>

There also should be no blank line there.

johannes