Re: [PATCH 6.6.y] bpf: Ensure reg is PTR_TO_STACK in process_iter_arg

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Fri, Aug 28, 2026 at 12:45:59PM +0800, Xu Yunxiang wrote:
> Currently KF_ARG_PTR_TO_ITER handling does not check reg->type.
> process_iter_arg() therefore accepts any register whose constant offset
> resolves to the stack slot of an initialized iterator — a bare SCALAR
> (kernel panic) as well as pointers to real kernel objects (map value,
> ctx).
> 
> This is the 6.6.y equivalent of 12659d28615d ("bpf: Ensure reg is
> PTR_TO_STACK in process_iter_arg"), which is in mainline since 6.13-rc
> and was backported to 6.12.5. The original commit was framed as
> completeness (align with process_dynptr_func) and was never queued for
> 6.6.y. 6.6 still lacks the type check (verified through 6.6.154).
> 
> The verbose argument index uses `regno` to match the surrounding 6.6
> messages in this function (later trees print regno - 1).
> The verifier_bits_iter.c hunk from 12659d28615d is omitted: that file
> does not exist in 6.6.
> 
> commit 12659d28615d upstream
> Fixes: 06accc8779c1 ("bpf: add support for open-coded iterator loops")
> Cc: stable@vger.kernel.org # 6.6.y
> 
> Signed-off-by: Xu Yunxiang <xyx2021@mail.ustc.edu.cn>

You lost all of the original authorship and signed-off-by lines, AND you
changed this from the original in a way and did not document that.

Please fix that up and resend.  See the thousands of examples on the
stable@vger.kernel.org list for examples of how to do this.

thanks,

greg k-h