On Fri, Oct 17, 2025 at 9:04 PM Xu Kuohai <[email protected]> wrote: > > From: Xu Kuohai <[email protected]> > > Add overwrite mode test for BPF ring buffer. The test creates a BPF ring > buffer in overwrite mode, then repeatedly reserves and commits records > to check if the ring buffer works as expected both before and after > overwriting occurs. > > Signed-off-by: Xu Kuohai <[email protected]> > --- > tools/testing/selftests/bpf/Makefile | 3 +- > .../selftests/bpf/prog_tests/ringbuf.c | 64 ++++++++++++ > .../bpf/progs/test_ringbuf_overwrite.c | 98 +++++++++++++++++++ > 3 files changed, 164 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/bpf/progs/test_ringbuf_overwrite.c > > diff --git a/tools/testing/selftests/bpf/Makefile > b/tools/testing/selftests/bpf/Makefile > index f00587d4ede6..43d133bf514d 100644 > --- a/tools/testing/selftests/bpf/Makefile > +++ b/tools/testing/selftests/bpf/Makefile > @@ -498,7 +498,8 @@ LINKED_SKELS := test_static_linked.skel.h > linked_funcs.skel.h \ > > LSKELS := fexit_sleep.c trace_printk.c trace_vprintk.c map_ptr_kern.c \ > core_kern.c core_kern_overflow.c test_ringbuf.c \ > - test_ringbuf_n.c test_ringbuf_map_key.c test_ringbuf_write.c > + test_ringbuf_n.c test_ringbuf_map_key.c test_ringbuf_write.c \ > + test_ringbuf_overwrite.c > > LSKELS_SIGNED := fentry_test.c fexit_test.c atomics.c > > diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c > b/tools/testing/selftests/bpf/prog_tests/ringbuf.c > index d1e4cb28a72c..5264af1dc768 100644 > --- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c > +++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c > @@ -17,6 +17,7 @@ > #include "test_ringbuf_n.lskel.h" > #include "test_ringbuf_map_key.lskel.h" > #include "test_ringbuf_write.lskel.h" > +#include "test_ringbuf_overwrite.lskel.h" > > #define EDONE 7777 > > @@ -497,6 +498,67 @@ static void ringbuf_map_key_subtest(void) > test_ringbuf_map_key_lskel__destroy(skel_map_key); > } > > +static void ringbuf_overwrite_mode_subtest(void) > +{ > + unsigned long size, len1, len2, len3, len4, len5; > + unsigned long expect_avail_data, expect_prod_pos, expect_over_pos; > + struct test_ringbuf_overwrite_lskel *skel; > + int err; > + > + skel = test_ringbuf_overwrite_lskel__open(); > + if (!ASSERT_OK_PTR(skel, "skel_open")) > + return; > + > + size = 0x1000;
this will fail on architecture with page size != 4KB, I adjusted this to use page_size, len1 to page_size / 2 and len2 to page_size / 4 > + len1 = 0x800; > + len2 = 0x400; > + len3 = size - len1 - len2 - BPF_RINGBUF_HDR_SZ * 3; /* 0x3e8 */ > + len4 = len3 - 8; /* 0x3e0 */ > + len5 = len3; /* retry with len3 */ > + [...]
