From aeb709c767aeca996e6011133e4f7bdb2a4af652 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 30 Sep 2026 09:59:20 +0000 Subject: selftests/bpf: Add a test for objects stuck in free_by_rcu_ttrace Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first free_bulk() starts RCU tasks trace GP and the rest of the elements are freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and waiting_for_gp_ttrace lists are empty. Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- samples/user_events/example.c | 73 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 samples/user_events/example.c (limited to 'samples/user_events/example.c') diff --git a/samples/user_events/example.c b/samples/user_events/example.c new file mode 100644 index 000000000..28165a096 --- /dev/null +++ b/samples/user_events/example.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2021, Microsoft Corporation. + * + * Authors: + * Beau Belgrave + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +const char *data_file = "/sys/kernel/tracing/user_events_data"; +int enabled = 0; + +static int event_reg(int fd, const char *command, int *write, int *enabled) +{ + struct user_reg reg = {0}; + + reg.size = sizeof(reg); + reg.enable_bit = 31; + reg.enable_size = sizeof(*enabled); + reg.enable_addr = (__u64)enabled; + reg.name_args = (__u64)command; + + if (ioctl(fd, DIAG_IOCSREG, ®) == -1) + return -1; + + *write = reg.write_index; + + return 0; +} + +int main(int argc, char **argv) +{ + int data_fd, write; + struct iovec io[2]; + __u32 count = 0; + + data_fd = open(data_file, O_RDWR); + + if (event_reg(data_fd, "test u32 count", &write, &enabled) == -1) + return errno; + + /* Setup iovec */ + io[0].iov_base = &write; + io[0].iov_len = sizeof(write); + io[1].iov_base = &count; + io[1].iov_len = sizeof(count); +ask: + printf("Press enter to check status...\n"); + getchar(); + + /* Check if anyone is listening */ + if (enabled) { + /* Yep, trace out our data */ + writev(data_fd, (const struct iovec *)io, 2); + + /* Increase the count */ + count++; + + printf("Something was attached, wrote data\n"); + } + + goto ask; + + return 0; +} -- cgit v1.3.1