On Thu, Aug 28, 2025 at 6:39 AM Nimrod Oren <noren@xxxxxxxxxx> wrote: > > On 25/08/2025 22:39, Amery Hung wrote: > > This patchset introduces a new kfunc bpf_xdp_pull_data() to allow > > pulling nonlinear xdp data. This may be useful when a driver places > > headers in fragments. When an xdp program would like to keep parsing > > packet headers using direct packet access, it can call > > bpf_xdp_pull_data() to make the header available in the linear data > > area. The kfunc can also be used to decapsulate the header in the > > nonlinear data, as currently there is no easy way to do this. > > I'm currently working on a series that converts the xdp_native program > to use dynptr for accessing header data. If accepted, it should provide > better performance, since dynptr can access without copying the data. > > > This patchset also tries to fix an issue in the mlx5e driver. The driver > > curretly assumes the packet layout to be unchanged after xdp program > > runs and may generate packet with corrupted data or trigger kernel warning > > if xdp programs calls layout-changing kfunc such as bpf_xdp_adjust_tail(), > > bpf_xdp_adjust_head() or bpf_xdp_pull_data() introduced in this set. > > Thanks for working on this! > > > Tested with the added bpf selftest using bpf test_run and also on > > mlx5e with the tools/testing/selftests/drivers/net/xdp.py. mlx5e with > > striding RQ will produce xdp_buff with empty linear data. > > xdp.test_xdp_native_pass_mb would fail to parse the header before this > > patchset. > > I got a crash when testing this series with the xdp_dummy program from > tools/testing/selftests/net/lib/. Need to make sure we're not breaking > compatibility for programs that keep the linear part empty. ping.py test ran successfully for me. Is this what you tried but crashed the kernel?
