On Mon, May 05, 2025 at 03:38:59PM +0900, Sergey Senozhatsky wrote:
> bpf_msleep_interruptible() puts a calling context into an
> interruptible sleep. This function is expected to be used
> for testing only (perhaps in conjunction with fault-injection)
> to simulate various execution delays or timeouts.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> ---
> include/linux/bpf.h | 1 +
> include/uapi/linux/bpf.h | 9 +++++++++
> kernel/bpf/helpers.c | 13 +++++++++++++
> kernel/trace/bpf_trace.c | 2 ++
> tools/include/uapi/linux/bpf.h | 9 +++++++++
> 5 files changed, 34 insertions(+)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 3f0cc89c0622..85bd1daaa7df 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -3392,6 +3392,7 @@ extern const struct bpf_func_proto bpf_get_retval_proto;
> extern const struct bpf_func_proto bpf_user_ringbuf_drain_proto;
> extern const struct bpf_func_proto bpf_cgrp_storage_get_proto;
> extern const struct bpf_func_proto bpf_cgrp_storage_delete_proto;
> +extern const struct bpf_func_proto bpf_msleep_interruptible_proto;
>
> const struct bpf_func_proto *tracing_prog_func_proto(
> enum bpf_func_id func_id, const struct bpf_prog *prog);
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 71d5ac83cf5d..cbbb6d70a7a3 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -5814,6 +5814,14 @@ union bpf_attr {
> * 0 on success.
> *
> * **-ENOENT** if the bpf_local_storage cannot be found.
> + *
> + * long bpf_msleep_interruptible(long timeout)
> + * Description
> + * Make the current task sleep until *timeout* milliseconds have
> + * elapsed or until a signal is received.
> + *
> + * Return
> + * The remaining time of the sleep duration in milliseconds.
> */
> #define ___BPF_FUNC_MAPPER(FN, ctx...) \
> FN(unspec, 0, ##ctx) \
> @@ -6028,6 +6036,7 @@ union bpf_attr {
> FN(user_ringbuf_drain, 209, ##ctx) \
> FN(cgrp_storage_get, 210, ##ctx) \
> FN(cgrp_storage_delete, 211, ##ctx) \
> + FN(msleep_interruptible, 212, ##ctx) \
> /* This helper list is effectively frozen. If you are trying to \
> * add a new helper, you should add a kfunc instead which has \
> * less stability guarantees. See Documentation/bpf/kfuncs.rst \
I noticed that you've written the newly proposed BPF helper in the
legacy BPF helper form, which I believe is now discouraged, as also
stated within the above comment. You probably want to respin this
patch series having written this newly proposed BPF helper in BPF
kfuncs [0] form instead.
Additionally, as part of your patch series I think you'll also want to
include some selftests.
[0] https://docs.kernel.org/bpf/kfuncs.html
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index e3a2662f4e33..0a3449c282f2 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -1905,6 +1905,19 @@ static const struct bpf_func_proto bpf_dynptr_data_proto = {
> .arg3_type = ARG_CONST_ALLOC_SIZE_OR_ZERO,
> };
>
> +BPF_CALL_1(bpf_msleep_interruptible, long, timeout)
> +{
> + return msleep_interruptible(timeout);
> +}
> +
> +const struct bpf_func_proto bpf_msleep_interruptible_proto = {
> + .func = bpf_msleep_interruptible,
> + .gpl_only = false,
> + .might_sleep = true,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_ANYTHING,
> +};
> +
> const struct bpf_func_proto bpf_get_current_task_proto __weak;
> const struct bpf_func_proto bpf_get_current_task_btf_proto __weak;
> const struct bpf_func_proto bpf_probe_read_user_proto __weak;
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 52c432a44aeb..8a0b96aed0c0 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1475,6 +1475,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> return &bpf_get_branch_snapshot_proto;
> case BPF_FUNC_find_vma:
> return &bpf_find_vma_proto;
> + case BPF_FUNC_msleep_interruptible:
> + return &bpf_msleep_interruptible_proto;
> default:
> break;
> }
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 71d5ac83cf5d..cbbb6d70a7a3 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -5814,6 +5814,14 @@ union bpf_attr {
> * 0 on success.
> *
> * **-ENOENT** if the bpf_local_storage cannot be found.
> + *
> + * long bpf_msleep_interruptible(long timeout)
> + * Description
> + * Make the current task sleep until *timeout* milliseconds have
> + * elapsed or until a signal is received.
> + *
> + * Return
> + * The remaining time of the sleep duration in milliseconds.
> */
> #define ___BPF_FUNC_MAPPER(FN, ctx...) \
> FN(unspec, 0, ##ctx) \
> @@ -6028,6 +6036,7 @@ union bpf_attr {
> FN(user_ringbuf_drain, 209, ##ctx) \
> FN(cgrp_storage_get, 210, ##ctx) \
> FN(cgrp_storage_delete, 211, ##ctx) \
> + FN(msleep_interruptible, 212, ##ctx) \
> /* This helper list is effectively frozen. If you are trying to \
> * add a new helper, you should add a kfunc instead which has \
> * less stability guarantees. See Documentation/bpf/kfuncs.rst \
> --
> 2.49.0.906.g1f30a19c02-goog
>
