| Message ID | 20180603225943.2370719-2-yhs@fb.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | bpf: implement bpf_get_current_cgroup_id() helper | expand |
On 06/04/2018 12:59 AM, Yonghong Song wrote: > bpf has been used extensively for tracing. For example, bcc > contains an almost full set of bpf-based tools to trace kernel > and user functions/events. Most tracing tools are currently > either filtered based on pid or system-wide. > > Containers have been used quite extensively in industry and > cgroup is often used together to provide resource isolation > and protection. Several processes may run inside the same > container. It is often desirable to get container-level tracing > results as well, e.g. syscall count, function count, I/O > activity, etc. > > This patch implements a new helper, bpf_get_current_cgroup_id(), > which will return cgroup id based on the cgroup within which > the current task is running. > > The later patch will provide an example to show that > userspace can get the same cgroup id so it could > configure a filter or policy in the bpf program based on > task cgroup id. > > The helper is currently implemented for tracing. It can > be added to other program types as well when needed. > > Acked-by: Alexei Starovoitov <ast@kernel.org> > Signed-off-by: Yonghong Song <yhs@fb.com> > --- > include/linux/bpf.h | 1 + > include/uapi/linux/bpf.h | 8 +++++++- > kernel/bpf/core.c | 1 + > kernel/bpf/helpers.c | 15 +++++++++++++++ > kernel/trace/bpf_trace.c | 2 ++ > 5 files changed, 26 insertions(+), 1 deletion(-) > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index bbe2974..995c3b1 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -746,6 +746,7 @@ extern const struct bpf_func_proto bpf_get_stackid_proto; > extern const struct bpf_func_proto bpf_get_stack_proto; > extern const struct bpf_func_proto bpf_sock_map_update_proto; > extern const struct bpf_func_proto bpf_sock_hash_update_proto; > +extern const struct bpf_func_proto bpf_get_current_cgroup_id_proto; > > /* Shared helpers among cBPF and eBPF. */ > void bpf_user_rnd_init_once(void); > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index f0b6608..18712b0 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -2070,6 +2070,11 @@ union bpf_attr { > * **CONFIG_SOCK_CGROUP_DATA** configuration option. > * Return > * The id is returned or 0 in case the id could not be retrieved. > + * > + * u64 bpf_get_current_cgroup_id(void) > + * Return > + * A 64-bit integer containing the current cgroup id based > + * on the cgroup within which the current task is running. > */ > #define __BPF_FUNC_MAPPER(FN) \ > FN(unspec), \ > @@ -2151,7 +2156,8 @@ union bpf_attr { > FN(lwt_seg6_action), \ > FN(rc_repeat), \ > FN(rc_keydown), \ > - FN(skb_cgroup_id), > + FN(skb_cgroup_id), \ > + FN(get_current_cgroup_id), > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > * function eBPF program intends to call > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c > index 527587d..9f14937 100644 > --- a/kernel/bpf/core.c > +++ b/kernel/bpf/core.c > @@ -1765,6 +1765,7 @@ const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; > const struct bpf_func_proto bpf_get_current_comm_proto __weak; > const struct bpf_func_proto bpf_sock_map_update_proto __weak; > const struct bpf_func_proto bpf_sock_hash_update_proto __weak; > +const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; > > const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) > { > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > index 3d24e23..73065e2 100644 > --- a/kernel/bpf/helpers.c > +++ b/kernel/bpf/helpers.c > @@ -179,3 +179,18 @@ const struct bpf_func_proto bpf_get_current_comm_proto = { > .arg1_type = ARG_PTR_TO_UNINIT_MEM, > .arg2_type = ARG_CONST_SIZE, > }; > + > +#ifdef CONFIG_CGROUPS > +BPF_CALL_0(bpf_get_current_cgroup_id) > +{ > + struct cgroup *cgrp = task_dfl_cgroup(current); > + > + return cgrp->kn->id.id; > +} > + > +const struct bpf_func_proto bpf_get_current_cgroup_id_proto = { > + .func = bpf_get_current_cgroup_id, > + .gpl_only = false, > + .ret_type = RET_INTEGER, > +}; > +#endif Nit: why not moving this function directly to bpf_trace.c? > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index 752992c..e2ab5b7 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -564,6 +564,8 @@ tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > return &bpf_get_prandom_u32_proto; > case BPF_FUNC_probe_read_str: > return &bpf_probe_read_str_proto; > + case BPF_FUNC_get_current_cgroup_id: > + return &bpf_get_current_cgroup_id_proto; When you have !CONFIG_CGROUPS, then it relies on the weak definition of the bpf_get_current_cgroup_id_proto, which I would think at latest in fixup_bpf_calls() bails out with 'kernel subsystem misconfigured func' due to func being NULL. Can't we just do the #ifdef CONFIG_CGROUPS around BPF_FUNC_get_current_cgroup_id case instead? Then we bail out normally with 'unknown func' when cgroups are not configured? > default: > return NULL; > } >
On Mon, Jun 04, 2018 at 11:08:35AM +0200, Daniel Borkmann wrote: > On 06/04/2018 12:59 AM, Yonghong Song wrote: > > bpf has been used extensively for tracing. For example, bcc > > contains an almost full set of bpf-based tools to trace kernel > > and user functions/events. Most tracing tools are currently > > either filtered based on pid or system-wide. > > > > Containers have been used quite extensively in industry and > > cgroup is often used together to provide resource isolation > > and protection. Several processes may run inside the same > > container. It is often desirable to get container-level tracing > > results as well, e.g. syscall count, function count, I/O > > activity, etc. > > > > This patch implements a new helper, bpf_get_current_cgroup_id(), > > which will return cgroup id based on the cgroup within which > > the current task is running. > > > > The later patch will provide an example to show that > > userspace can get the same cgroup id so it could > > configure a filter or policy in the bpf program based on > > task cgroup id. > > > > The helper is currently implemented for tracing. It can > > be added to other program types as well when needed. > > > > Acked-by: Alexei Starovoitov <ast@kernel.org> > > Signed-off-by: Yonghong Song <yhs@fb.com> > > --- > > include/linux/bpf.h | 1 + > > include/uapi/linux/bpf.h | 8 +++++++- > > kernel/bpf/core.c | 1 + > > kernel/bpf/helpers.c | 15 +++++++++++++++ > > kernel/trace/bpf_trace.c | 2 ++ > > 5 files changed, 26 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > > index bbe2974..995c3b1 100644 > > --- a/include/linux/bpf.h > > +++ b/include/linux/bpf.h > > @@ -746,6 +746,7 @@ extern const struct bpf_func_proto bpf_get_stackid_proto; > > extern const struct bpf_func_proto bpf_get_stack_proto; > > extern const struct bpf_func_proto bpf_sock_map_update_proto; > > extern const struct bpf_func_proto bpf_sock_hash_update_proto; > > +extern const struct bpf_func_proto bpf_get_current_cgroup_id_proto; > > > > /* Shared helpers among cBPF and eBPF. */ > > void bpf_user_rnd_init_once(void); > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > > index f0b6608..18712b0 100644 > > --- a/include/uapi/linux/bpf.h > > +++ b/include/uapi/linux/bpf.h > > @@ -2070,6 +2070,11 @@ union bpf_attr { > > * **CONFIG_SOCK_CGROUP_DATA** configuration option. > > * Return > > * The id is returned or 0 in case the id could not be retrieved. > > + * > > + * u64 bpf_get_current_cgroup_id(void) > > + * Return > > + * A 64-bit integer containing the current cgroup id based > > + * on the cgroup within which the current task is running. > > */ > > #define __BPF_FUNC_MAPPER(FN) \ > > FN(unspec), \ > > @@ -2151,7 +2156,8 @@ union bpf_attr { > > FN(lwt_seg6_action), \ > > FN(rc_repeat), \ > > FN(rc_keydown), \ > > - FN(skb_cgroup_id), > > + FN(skb_cgroup_id), \ > > + FN(get_current_cgroup_id), > > > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > > * function eBPF program intends to call > > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c > > index 527587d..9f14937 100644 > > --- a/kernel/bpf/core.c > > +++ b/kernel/bpf/core.c > > @@ -1765,6 +1765,7 @@ const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; > > const struct bpf_func_proto bpf_get_current_comm_proto __weak; > > const struct bpf_func_proto bpf_sock_map_update_proto __weak; > > const struct bpf_func_proto bpf_sock_hash_update_proto __weak; > > +const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; > > > > const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) > > { > > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > > index 3d24e23..73065e2 100644 > > --- a/kernel/bpf/helpers.c > > +++ b/kernel/bpf/helpers.c > > @@ -179,3 +179,18 @@ const struct bpf_func_proto bpf_get_current_comm_proto = { > > .arg1_type = ARG_PTR_TO_UNINIT_MEM, > > .arg2_type = ARG_CONST_SIZE, > > }; > > + > > +#ifdef CONFIG_CGROUPS > > +BPF_CALL_0(bpf_get_current_cgroup_id) > > +{ > > + struct cgroup *cgrp = task_dfl_cgroup(current); > > + > > + return cgrp->kn->id.id; > > +} > > + > > +const struct bpf_func_proto bpf_get_current_cgroup_id_proto = { > > + .func = bpf_get_current_cgroup_id, > > + .gpl_only = false, > > + .ret_type = RET_INTEGER, > > +}; > > +#endif > > Nit: why not moving this function directly to bpf_trace.c? my preference would be to keep it in helpers.c as-is. imo bpf_trace.c is only for things that depend on kernel/trace/ > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > > index 752992c..e2ab5b7 100644 > > --- a/kernel/trace/bpf_trace.c > > +++ b/kernel/trace/bpf_trace.c > > @@ -564,6 +564,8 @@ tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > > return &bpf_get_prandom_u32_proto; > > case BPF_FUNC_probe_read_str: > > return &bpf_probe_read_str_proto; > > + case BPF_FUNC_get_current_cgroup_id: > > + return &bpf_get_current_cgroup_id_proto; > > When you have !CONFIG_CGROUPS, then it relies on the weak definition of the > bpf_get_current_cgroup_id_proto, which I would think at latest in fixup_bpf_calls() > bails out with 'kernel subsystem misconfigured func' due to func being NULL. > > Can't we just do the #ifdef CONFIG_CGROUPS around BPF_FUNC_get_current_cgroup_id > case instead? Then we bail out normally with 'unknown func' when cgroups are > not configured? good idea.
On 6/4/18 7:58 AM, Alexei Starovoitov wrote: > On Mon, Jun 04, 2018 at 11:08:35AM +0200, Daniel Borkmann wrote: >> On 06/04/2018 12:59 AM, Yonghong Song wrote: >>> bpf has been used extensively for tracing. For example, bcc >>> contains an almost full set of bpf-based tools to trace kernel >>> and user functions/events. Most tracing tools are currently >>> either filtered based on pid or system-wide. >>> >>> Containers have been used quite extensively in industry and >>> cgroup is often used together to provide resource isolation >>> and protection. Several processes may run inside the same >>> container. It is often desirable to get container-level tracing >>> results as well, e.g. syscall count, function count, I/O >>> activity, etc. >>> >>> This patch implements a new helper, bpf_get_current_cgroup_id(), >>> which will return cgroup id based on the cgroup within which >>> the current task is running. >>> >>> The later patch will provide an example to show that >>> userspace can get the same cgroup id so it could >>> configure a filter or policy in the bpf program based on >>> task cgroup id. >>> >>> The helper is currently implemented for tracing. It can >>> be added to other program types as well when needed. >>> >>> Acked-by: Alexei Starovoitov <ast@kernel.org> >>> Signed-off-by: Yonghong Song <yhs@fb.com> >>> --- >>> include/linux/bpf.h | 1 + >>> include/uapi/linux/bpf.h | 8 +++++++- >>> kernel/bpf/core.c | 1 + >>> kernel/bpf/helpers.c | 15 +++++++++++++++ >>> kernel/trace/bpf_trace.c | 2 ++ >>> 5 files changed, 26 insertions(+), 1 deletion(-) >>> >>> diff --git a/include/linux/bpf.h b/include/linux/bpf.h >>> index bbe2974..995c3b1 100644 >>> --- a/include/linux/bpf.h >>> +++ b/include/linux/bpf.h >>> @@ -746,6 +746,7 @@ extern const struct bpf_func_proto bpf_get_stackid_proto; >>> extern const struct bpf_func_proto bpf_get_stack_proto; >>> extern const struct bpf_func_proto bpf_sock_map_update_proto; >>> extern const struct bpf_func_proto bpf_sock_hash_update_proto; >>> +extern const struct bpf_func_proto bpf_get_current_cgroup_id_proto; >>> >>> /* Shared helpers among cBPF and eBPF. */ >>> void bpf_user_rnd_init_once(void); >>> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h >>> index f0b6608..18712b0 100644 >>> --- a/include/uapi/linux/bpf.h >>> +++ b/include/uapi/linux/bpf.h >>> @@ -2070,6 +2070,11 @@ union bpf_attr { >>> * **CONFIG_SOCK_CGROUP_DATA** configuration option. >>> * Return >>> * The id is returned or 0 in case the id could not be retrieved. >>> + * >>> + * u64 bpf_get_current_cgroup_id(void) >>> + * Return >>> + * A 64-bit integer containing the current cgroup id based >>> + * on the cgroup within which the current task is running. >>> */ >>> #define __BPF_FUNC_MAPPER(FN) \ >>> FN(unspec), \ >>> @@ -2151,7 +2156,8 @@ union bpf_attr { >>> FN(lwt_seg6_action), \ >>> FN(rc_repeat), \ >>> FN(rc_keydown), \ >>> - FN(skb_cgroup_id), >>> + FN(skb_cgroup_id), \ >>> + FN(get_current_cgroup_id), >>> >>> /* integer value in 'imm' field of BPF_CALL instruction selects which helper >>> * function eBPF program intends to call >>> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c >>> index 527587d..9f14937 100644 >>> --- a/kernel/bpf/core.c >>> +++ b/kernel/bpf/core.c >>> @@ -1765,6 +1765,7 @@ const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; >>> const struct bpf_func_proto bpf_get_current_comm_proto __weak; >>> const struct bpf_func_proto bpf_sock_map_update_proto __weak; >>> const struct bpf_func_proto bpf_sock_hash_update_proto __weak; >>> +const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; >>> >>> const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) >>> { >>> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c >>> index 3d24e23..73065e2 100644 >>> --- a/kernel/bpf/helpers.c >>> +++ b/kernel/bpf/helpers.c >>> @@ -179,3 +179,18 @@ const struct bpf_func_proto bpf_get_current_comm_proto = { >>> .arg1_type = ARG_PTR_TO_UNINIT_MEM, >>> .arg2_type = ARG_CONST_SIZE, >>> }; >>> + >>> +#ifdef CONFIG_CGROUPS >>> +BPF_CALL_0(bpf_get_current_cgroup_id) >>> +{ >>> + struct cgroup *cgrp = task_dfl_cgroup(current); >>> + >>> + return cgrp->kn->id.id; >>> +} >>> + >>> +const struct bpf_func_proto bpf_get_current_cgroup_id_proto = { >>> + .func = bpf_get_current_cgroup_id, >>> + .gpl_only = false, >>> + .ret_type = RET_INTEGER, >>> +}; >>> +#endif >> >> Nit: why not moving this function directly to bpf_trace.c? > > my preference would be to keep it in helpers.c as-is. > imo bpf_trace.c is only for things that depend on kernel/trace/ > >>> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c >>> index 752992c..e2ab5b7 100644 >>> --- a/kernel/trace/bpf_trace.c >>> +++ b/kernel/trace/bpf_trace.c >>> @@ -564,6 +564,8 @@ tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) >>> return &bpf_get_prandom_u32_proto; >>> case BPF_FUNC_probe_read_str: >>> return &bpf_probe_read_str_proto; >>> + case BPF_FUNC_get_current_cgroup_id: >>> + return &bpf_get_current_cgroup_id_proto; >> >> When you have !CONFIG_CGROUPS, then it relies on the weak definition of the >> bpf_get_current_cgroup_id_proto, which I would think at latest in fixup_bpf_calls() >> bails out with 'kernel subsystem misconfigured func' due to func being NULL. >> >> Can't we just do the #ifdef CONFIG_CGROUPS around BPF_FUNC_get_current_cgroup_id >> case instead? Then we bail out normally with 'unknown func' when cgroups are >> not configured? Thanks. Will send a followup patch soon. > > good idea. >
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index bbe2974..995c3b1 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -746,6 +746,7 @@ extern const struct bpf_func_proto bpf_get_stackid_proto; extern const struct bpf_func_proto bpf_get_stack_proto; extern const struct bpf_func_proto bpf_sock_map_update_proto; extern const struct bpf_func_proto bpf_sock_hash_update_proto; +extern const struct bpf_func_proto bpf_get_current_cgroup_id_proto; /* Shared helpers among cBPF and eBPF. */ void bpf_user_rnd_init_once(void); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index f0b6608..18712b0 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2070,6 +2070,11 @@ union bpf_attr { * **CONFIG_SOCK_CGROUP_DATA** configuration option. * Return * The id is returned or 0 in case the id could not be retrieved. + * + * u64 bpf_get_current_cgroup_id(void) + * Return + * A 64-bit integer containing the current cgroup id based + * on the cgroup within which the current task is running. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2151,7 +2156,8 @@ union bpf_attr { FN(lwt_seg6_action), \ FN(rc_repeat), \ FN(rc_keydown), \ - FN(skb_cgroup_id), + FN(skb_cgroup_id), \ + FN(get_current_cgroup_id), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 527587d..9f14937 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1765,6 +1765,7 @@ const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; const struct bpf_func_proto bpf_get_current_comm_proto __weak; const struct bpf_func_proto bpf_sock_map_update_proto __weak; const struct bpf_func_proto bpf_sock_hash_update_proto __weak; +const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) { diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 3d24e23..73065e2 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -179,3 +179,18 @@ const struct bpf_func_proto bpf_get_current_comm_proto = { .arg1_type = ARG_PTR_TO_UNINIT_MEM, .arg2_type = ARG_CONST_SIZE, }; + +#ifdef CONFIG_CGROUPS +BPF_CALL_0(bpf_get_current_cgroup_id) +{ + struct cgroup *cgrp = task_dfl_cgroup(current); + + return cgrp->kn->id.id; +} + +const struct bpf_func_proto bpf_get_current_cgroup_id_proto = { + .func = bpf_get_current_cgroup_id, + .gpl_only = false, + .ret_type = RET_INTEGER, +}; +#endif diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 752992c..e2ab5b7 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -564,6 +564,8 @@ tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_prandom_u32_proto; case BPF_FUNC_probe_read_str: return &bpf_probe_read_str_proto; + case BPF_FUNC_get_current_cgroup_id: + return &bpf_get_current_cgroup_id_proto; default: return NULL; }