kernel/samples/bpf/xdp_rxq_info_user.c, branch linux-5.10.y

samples/bpf: Set rlimit for memlock to infinity in all samples

2020-10-27T21:46:17Z

The memlock rlimit is a notorious source of failure for BPF programs. Most of the samples just set it to infinity, but a few used a lower limit. The problem with unconditionally setting a lower limit is that this will also override the limit if the system-wide setting is *higher* than the limit being set, which can lead to failures on systems that lock a lot of memory, but set 'ulimit -l' to unlimited before running a sample. One fix for this is to only conditionally set the limit if the current limit is lower, but it is simpler to just unify all the samples and have them all set the limit to infinity. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Acked-by: Jesper Dangaard Brouer Link: https://lore.kernel.org/bpf/20201026233623.91728-1-toke@redhat.com

bpf, xdp, samples: Fix null pointer dereference in *_user code

2020-06-16T12:55:35Z

Memset on the pointer right after malloc can cause a NULL pointer deference if it failed to allocate memory. A simple fix is to replace malloc()/memset() pair with a simple call to calloc(). Fixes: 0fca931a6f21 ("samples/bpf: program demonstrating access to xdp_rxq_info") Signed-off-by: Gaurav Singh Signed-off-by: Daniel Borkmann Acked-by: Jesper Dangaard Brouer Acked-by: John Fastabend

samples/bpf: Use consistent include paths for libbpf

2020-01-21T00:37:45Z

Fix all files in samples/bpf to include libbpf header files with the bpf/ prefix, to be consistent with external users of the library. Also ensure that all includes of exported libbpf header files (those that are exported on 'make install' of the library) use bracketed includes instead of quoted. To make sure no new files are introduced that doesn't include the bpf/ prefix in its include, remove tools/lib/bpf from the include path entirely, and use tools/lib instead. Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir") Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Acked-by: Jesper Dangaard Brouer Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/157952560911.1683545.8795966751309534150.stgit@toke.dk

samples/bpf: Attach XDP programs in driver mode by default

2019-12-16T15:05:38Z

When attaching XDP programs, userspace can set flags to request the attach mode (generic/SKB mode, driver mode or hw offloaded mode). If no such flags are requested, the kernel will attempt to attach in driver mode, and then silently fall back to SKB mode if this fails. The silent fallback is a major source of user confusion, as users will try to load a program on a device without XDP support, and instead of an error they will get the silent fallback behaviour, not notice, and then wonder why performance is not what they were expecting. In an attempt to combat this, let's switch all the samples to default to explicitly requesting driver-mode attach. As part of this, ensure that all the userspace utilities have a switch to enable SKB mode. For those that have a switch to request driver mode, keep it but turn it into a no-op. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Acked-by: Jesper Dangaard Brouer Acked-by: David Ahern Link: https://lore.kernel.org/bpf/20191216110742.364456-1-toke@redhat.com

samples/bpf: Fix broken xdp_rxq_info due to map order assumptions

2019-12-05T01:54:15Z

In the days of using bpf_load.c the order in which the 'maps' sections were defines in BPF side (*_kern.c) file, were used by userspace side to identify the map via using the map order as an index. In effect the order-index is created based on the order the maps sections are stored in the ELF-object file, by the LLVM compiler. This have also carried over in libbpf via API bpf_map__next(NULL, obj) to extract maps in the order libbpf parsed the ELF-object file. When BTF based maps were introduced a new section type ".maps" were created. I found that the LLVM compiler doesn't create the ".maps" sections in the order they are defined in the C-file. The order in the ELF file is based on the order the map pointer is referenced in the code. This combination of changes lead to xdp_rxq_info mixing up the map file-descriptors in userspace, resulting in very broken behaviour, but without warning the user. This patch fix issue by instead using bpf_object__find_map_by_name() to find maps via their names. (Note, this is the ELF name, which can be longer than the name the kernel retains). Fixes: be5bca44aa6b ("samples: bpf: convert some XDP samples from bpf_load to libbpf") Fixes: 451d1dc886b5 ("samples: bpf: update map definition to new syntax BTF-defined map") Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Alexei Starovoitov Acked-by: Toke Høiland-Jørgensen Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/157529025128.29832.5953245340679936909.stgit@firesoul

samples: bpf: Update outdated error message

2019-11-09T03:19:43Z

Currently, under samples, several methods are being used to load bpf program. Since using libbpf is preferred solution, lots of previously used 'load_bpf_file' from bpf_load are replaced with 'bpf_prog_load_xattr' from libbpf. But some of the error messages still show up as 'load_bpf_file' instead of 'bpf_prog_load_xattr'. This commit fixes outdated errror messages under samples and fixes some code style issues. Signed-off-by: Daniel T. Lee Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20191107005153.31541-2-danieltimlee@gmail.com

samples: bpf: refactor header include path

2019-06-17T22:28:36Z

Currently, header inclusion in each file is inconsistent. For example, "libbpf.h" header is included as multiple ways. #include "bpf/libbpf.h" #include "libbpf.h" Due to commit b552d33c80a9 ("samples/bpf: fix include path in Makefile"), $(srctree)/tools/lib/bpf/ path had been included during build, path "bpf/" in header isn't necessary anymore. This commit removes path "bpf/" in header inclusion. Signed-off-by: Daniel T. Lee Signed-off-by: Daniel Borkmann

samples/bpf: Check the prog id before exiting

2019-02-01T22:37:51Z

Check the program id within the signal handler on polling xdp samples that were previously converted to libbpf usage. Avoid the situation of unloading the program that was not attached by sample that is exiting. Handle also the case where bpf_get_link_xdp_id didn't exit with an error but the xdp program was not found on an interface. Reported-by: Michal Papaj Reported-by: Jakub Spizewski Signed-off-by: Maciej Fijalkowski Reviewed-by: Jakub Kicinski Signed-off-by: Daniel Borkmann

samples/bpf: Add a "force" flag to XDP samples

2019-02-01T22:37:51Z

Make xdp samples consistent with iproute2 behavior and set the XDP_FLAGS_UPDATE_IF_NOEXIST by default when setting the xdp program on interface. Provide an option for user to force the program loading, which as a result will not include the mentioned flag in bpf_set_link_xdp_fd call. Signed-off-by: Maciej Fijalkowski Reviewed-by: Jakub Kicinski Acked-by: John Fastabend Signed-off-by: Daniel Borkmann

samples/bpf: all XDP samples should unload xdp/bpf prog on SIGTERM

2018-08-16T19:55:32Z

It is common XDP practice to unload/deattach the XDP bpf program, when the XDP sample program is Ctrl-C interrupted (SIGINT) or killed (SIGTERM). The samples/bpf programs xdp_redirect_cpu and xdp_rxq_info, forgot to trap signal SIGTERM (which is the default signal used by the kill command). This was discovered by Red Hat QA, which automated scripts depend on killing the XDP sample program after a timeout period. Fixes: fad3917e361b ("samples/bpf: add cpumap sample program xdp_redirect_cpu") Fixes: 0fca931a6f21 ("samples/bpf: program demonstrating access to xdp_rxq_info") Reported-by: Jean-Tsung Hsiao Signed-off-by: Jesper Dangaard Brouer Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann