diff options
Diffstat (limited to '')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c b/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c index 50e59a2e142e..442f4ca39fd7 100644 --- a/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c @@ -2,7 +2,6 @@ /* Copyright (c) 2020 Facebook */ #include "bpf_iter.h" #include <bpf/bpf_helpers.h> -#include <bpf/bpf_tracing.h> char _license[] SEC("license") = "GPL"; @@ -35,3 +34,35 @@ int dump_task_stack(struct bpf_iter__task *ctx) return 0; } + +int num_user_stacks = 0; + +SEC("iter/task") +int get_task_user_stacks(struct bpf_iter__task *ctx) +{ + struct seq_file *seq = ctx->meta->seq; + struct task_struct *task = ctx->task; + uint64_t buf_sz = 0; + int64_t res; + + if (task == (void *)0) + return 0; + + res = bpf_get_task_stack(task, entries, + MAX_STACK_TRACE_DEPTH * SIZE_OF_ULONG, BPF_F_USER_STACK); + if (res <= 0) + return 0; + + /* Only one task, the current one, should succeed */ + ++num_user_stacks; + + buf_sz += res; + + /* If the verifier doesn't refine bpf_get_task_stack res, and instead + * assumes res is entirely unknown, this program will fail to load as + * the verifier will believe that max buf_sz value allows reading + * past the end of entries in bpf_seq_write call + */ + bpf_seq_write(seq, &entries, buf_sz); + return 0; +} |