On 2/25/22 3:43 PM, Hao Luo wrote:
Add a new type of bpf tracepoints: sleepable tracepoints, which allows
the handler to make calls that may sleep. With sleepable tracepoints, a
set of syscall helpers (which may sleep) may also be called from
sleepable tracepoints.
There are some old discussions on sleepable tracepoints, maybe
worthwhile to take a look.
https://lore.kernel.org/bpf/20210218222125.46565-5-mjeanson@xxxxxxxxxxxx/T/
In the following patches, we will whitelist some tracepoints to be
sleepable.
Signed-off-by: Hao Luo <haoluo@xxxxxxxxxx>
---
include/linux/bpf.h | 10 +++++++-
include/linux/tracepoint-defs.h | 1 +
include/trace/bpf_probe.h | 22 ++++++++++++++----
kernel/bpf/syscall.c | 41 +++++++++++++++++++++++----------
kernel/trace/bpf_trace.c | 5 ++++
5 files changed, 61 insertions(+), 18 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index c36eeced3838..759ade7b24b3 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1810,6 +1810,9 @@ struct bpf_prog *bpf_prog_by_id(u32 id);
struct bpf_link *bpf_link_by_id(u32 id);
const struct bpf_func_proto *bpf_base_func_proto(enum bpf_func_id func_id);
+const struct bpf_func_proto *
+tracing_prog_syscall_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog);
+
void bpf_task_storage_free(struct task_struct *task);
bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog);
const struct btf_func_model *
@@ -1822,7 +1825,6 @@ struct bpf_core_ctx {
int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
int relo_idx, void *insn);
-
#else /* !CONFIG_BPF_SYSCALL */
static inline struct bpf_prog *bpf_prog_get(u32 ufd)
{
@@ -2011,6 +2013,12 @@ bpf_base_func_proto(enum bpf_func_id func_id)
return NULL;
}
+static inline struct bpf_func_proto *
+tracing_prog_syscall_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+ return NULL;
+}
+
static inline void bpf_task_storage_free(struct task_struct *task)
{
}
diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h
index e7c2276be33e..c73c7ab3680e 100644
--- a/include/linux/tracepoint-defs.h
+++ b/include/linux/tracepoint-defs.h
@@ -51,6 +51,7 @@ struct bpf_raw_event_map {
void *bpf_func;
u32 num_args;
u32 writable_size;
+ u32 sleepable;
} __aligned(32);
/*
[...]
