The attach_type_name definition was removed in commit 1ba5ad36e0
("bpftool: Use libbpf_bpf_attach_type_str"). Remove its forward
declaration in main.h as well.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220630093638.25916-1-tklauser@distanz.ch
Bpftool used to bump the memlock rlimit to make sure to be able to load
BPF objects. After the kernel has switched to memcg-based memory
accounting [0] in 5.11, bpftool has relied on libbpf to probe the system
for memcg-based accounting support and for raising the rlimit if
necessary [1]. But this was later reverted, because the probe would
sometimes fail, resulting in bpftool not being able to load all required
objects [2].
Here we add a more efficient probe, in bpftool itself. We first lower
the rlimit to 0, then we attempt to load a BPF object (and finally reset
the rlimit): if the load succeeds, then memcg-based memory accounting is
supported.
This approach was earlier proposed for the probe in libbpf itself [3],
but given that the library may be used in multithreaded applications,
the probe could have undesirable consequences if one thread attempts to
lock kernel memory while memlock rlimit is at 0. Since bpftool is
single-threaded and the rlimit is process-based, this is fine to do in
bpftool itself.
This probe was inspired by the similar one from the cilium/ebpf Go
library [4].
[0] commit 97306be45f ("Merge branch 'switch to memcg-based memory accounting'")
[1] commit a777e18f1b ("bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK")
[2] commit 6b4384ff10 ("Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"")
[3] https://lore.kernel.org/bpf/20220609143614.97837-1-quentin@isovalent.com/t/#u
[4] https://github.com/cilium/ebpf/blob/v0.9.0/rlimit/rlimit.go#L39
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/bpf/20220629111351.47699-1-quentin@isovalent.com
Stanislav Fomichev says:
====================
This series implements new lsm flavor for attaching per-cgroup programs to
existing lsm hooks. The cgroup is taken out of 'current', unless
the first argument of the hook is 'struct socket'. In this case,
the cgroup association is taken out of socket. The attachment
looks like a regular per-cgroup attachment: we add new BPF_LSM_CGROUP
attach type which, together with attach_btf_id, signals per-cgroup lsm.
Behind the scenes, we allocate trampoline shim program and
attach to lsm. This program looks up cgroup from current/socket
and runs cgroup's effective prog array. The rest of the per-cgroup BPF
stays the same: hierarchy, local storage, retval conventions
(return 1 == success).
Current limitations:
* haven't considered sleepable bpf; can be extended later on
* not sure the verifier does the right thing with null checks;
see latest selftest for details
* total of 10 (global) per-cgroup LSM attach points
v11:
- Martin: address selftest memory & fd leaks
- Martin: address moving into root (instead have another temp leaf cgroup)
- Martin: move tools/include/uapi/linux/bpf.h change from libbpf patch
into 'sync tools' patch
v10:
- Martin: reword commit message, drop outdated items
- Martin: remove rcu_real_lock from __cgroup_bpf_run_lsm_current
- Martin: remove CONFIG_BPF_LSM from cgroup_bpf_release
- Martin: fix leaking shim reference in bpf_cgroup_link_release
- Martin: WARN_ON_ONCE for bpf_trampoline_lookup in bpf_trampoline_unlink_cgroup_shim
- Martin: sync tools/include/linux/btf_ids.h
- Martin: move progs/flags closer to the places where they are used in __cgroup_bpf_query
- Martin: remove sk_clone_security & sctp_bind_connect from bpf_lsm_locked_sockopt_hooks
- Martin: try to determine vmlinux btf_id in bpftool
- Martin: update tools header in a separate commit
- Quentin: do libbpf_find_kernel_btf from the ops that need it
- lkp@intel.com: another build failure
v9:
Major change since last version is the switch to bpf_setsockopt to
change the socket state instead of letting the progs poke socket directly.
This, in turn, highlights the challenge that we need to care about whether
the socket is locked or not when we call bpf_setsockopt. (with my original
example selftest, the hooks are running early in the init phase for this
not to matter).
For now, I've added two btf id lists:
* hooks where we know the socket is locked and it's safe to call bpf_setsockopt
* hooks where we know the socket is _not_ locked, but the hook works on
the socket that's not yet exposed to userspace so it should be safe
(for this mode, special new set of bpf_{s,g}etsockopt helpers
is added; they don't have sock_owned_by_me check)
Going forward, for the rest of the hooks, this might be a good motivation
to expand lsm cgroup to support sleeping bpf and allow the callers to
lock/unlock sockets or have a new bpf_setsockopt variant that does the
locking.
- ifdef around cleanup in cgroup_bpf_release
- Andrii: a few nits in libbpf patches
- Martin: remove unused btf_id_set_index
- Martin: bring back refcnt for cgroup_atype
- Martin: make __cgroup_bpf_query a bit more readable
- Martin: expose dst_prog->aux->attach_btf as attach_btf_obj_id as well
- Martin: reorg check_return_code path for BPF_LSM_CGROUP
- Martin: return directly from check_helper_call (instead of goto err)
- Martin: add note to new warning in check_return_code, print only for void hooks
- Martin: remove confusing shim reuse
- Martin: use bpf_{s,g}etsockopt instead of poking into socket data
- Martin: use CONFIG_CGROUP_BPF in bpf_prog_alloc_no_stats/bpf_prog_free_deferred
v8:
- CI: fix compile issue
- CI: fix broken bpf_cookie
- Yonghong: remove __bpf_trampoline_unlink_prog comment
- Yonghong: move cgroup_atype around to fill the gap
- Yonghong: make bpf_lsm_find_cgroup_shim void
- Yonghong: rename regs to args
- Yonghong: remove if(current) check
- Martin: move refcnt into bpf_link
- Martin: move shim management to bpf_link ops
- Martin: use cgroup_atype for shim only
- Martin: go back to arrays for managing cgroup_atype(s)
- Martin: export bpf_obj_id(aux->attach_btf)
- Andrii: reorder SEC_DEF("lsm_cgroup+")
- Andrii: OPTS_SET instead of OPTS_HAS
- Andrii: rename attach_btf_func_id
- Andrii: move into 1.0 map
v7:
- there were a lot of comments last time, hope I didn't forget anything,
some of the bigger ones:
- Martin: use/extend BTF_SOCK_TYPE_SOCKET
- Martin: expose bpf_set_retval
- Martin: reject 'return 0' at the verifier for 'void' hooks
- Martin: prog_query returns all BPF_LSM_CGROUP, prog_info
returns attach_btf_func_id
- Andrii: split libbpf changes
- Andrii: add field access test to test_progs, not test_verifier (still
using asm though)
- things that I haven't addressed, stating them here explicitly, let
me know if some of these are still problematic:
1. Andrii: exposing only link-based api: seems like the changes
to support non-link-based ones are minimal, couple of lines,
so seems like it worth having it?
2. Alexei: applying cgroup_atype for all cgroup hooks, not only
cgroup lsm: looks a bit harder to apply everywhere that I
originally thought; with lsm cgroup, we have a shim_prog pointer where
we store cgroup_atype; for non-lsm programs, we don't have a
trace program where to store it, so we still need some kind
of global table to map from "static" hook to "dynamic" slot.
So I'm dropping this "can be easily extended" clause from the
description for now. I have converted this whole machinery
to an RCU-managed list to remove synchronize_rcu().
- also note that I had to introduce new bpf_shim_tramp_link and
moved refcnt there; we need something to manage new bpf_tramp_link
v6:
- remove active count & stats for shim program (Martin KaFai Lau)
- remove NULL/error check for btf_vmlinux (Martin)
- don't check cgroup_atype in bpf_cgroup_lsm_shim_release (Martin)
- use old_prog (instead of passed one) in __cgroup_bpf_detach (Martin)
- make sure attach_btf_id is the same in __cgroup_bpf_replace (Martin)
- enable cgroup local storage and test it (Martin)
- properly implement prog query and add bpftool & tests (Martin)
- prohibit non-shared cgroup storage mode for BPF_LSM_CGROUP (Martin)
v5:
- __cgroup_bpf_run_lsm_socket remove NULL sock/sk checks (Martin KaFai Lau)
- __cgroup_bpf_run_lsm_{socket,current} s/prog/shim_prog/ (Martin)
- make sure bpf_lsm_find_cgroup_shim works for hooks without args (Martin)
- __cgroup_bpf_attach make sure attach_btf_id is the same when replacing (Martin)
- call bpf_cgroup_lsm_shim_release only for LSM_CGROUP (Martin)
- drop BPF_LSM_CGROUP from bpf_attach_type_to_tramp (Martin)
- drop jited check from cgroup_shim_find (Martin)
- new patch to convert cgroup_bpf to hlist_node (Jakub Sitnicki)
- new shim flavor for 'struct sock' + list of exceptions (Martin)
v4:
- fix build when jit is on but syscall is off
v3:
- add BPF_LSM_CGROUP to bpftool
- use simple int instead of refcnt_t (to avoid use-after-free
false positive)
v2:
- addressed build bot failures
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Implement bpf_prog_query_opts as a more expendable version of
bpf_prog_query. Expose new prog_attach_flags and attach_btf_func_id as
well:
* prog_attach_flags is a per-program attach_type; relevant only for
lsm cgroup program which might have different attach_flags
per attach_btf_id
* attach_btf_func_id is a new field expose for prog_query which
specifies real btf function id for lsm cgroup attachments
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220628174314.1216643-10-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
lsm_cgroup/ is the prefix for BPF_LSM_CGROUP.
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220628174314.1216643-9-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Has been slowly getting out of sync, let's update it.
resolve_btfids usage has been updated to match the header changes.
Also bring new parts of tools/include/uapi/linux/bpf.h.
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220628174314.1216643-8-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
I don't see how to make it nice without introducing btf id lists
for the hooks where these helpers are allowed. Some LSM hooks
work on the locked sockets, some are triggering early and
don't grab any locks, so have two lists for now:
1. LSM hooks which trigger under socket lock - minority of the hooks,
but ideal case for us, we can expose existing BTF-based helpers
2. LSM hooks which trigger without socket lock, but they trigger
early in the socket creation path where it should be safe to
do setsockopt without any locks
3. The rest are prohibited. I'm thinking that this use-case might
be a good gateway to sleeping lsm cgroup hooks in the future.
We can either expose lock/unlock operations (and add tracking
to the verifier) or have another set of bpf_setsockopt
wrapper that grab the locks and might sleep.
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220628174314.1216643-7-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We have two options:
1. Treat all BPF_LSM_CGROUP the same, regardless of attach_btf_id
2. Treat BPF_LSM_CGROUP+attach_btf_id as a separate hook point
I was doing (2) in the original patch, but switching to (1) here:
* bpf_prog_query returns all attached BPF_LSM_CGROUP programs
regardless of attach_btf_id
* attach_btf_id is exported via bpf_prog_info
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220628174314.1216643-6-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow attaching to lsm hooks in the cgroup context.
Attaching to per-cgroup LSM works exactly like attaching
to other per-cgroup hooks. New BPF_LSM_CGROUP is added
to trigger new mode; the actual lsm hook we attach to is
signaled via existing attach_btf_id.
For the hooks that have 'struct socket' or 'struct sock' as its first
argument, we use the cgroup associated with that socket. For the rest,
we use 'current' cgroup (this is all on default hierarchy == v2 only).
Note that for some hooks that work on 'struct sock' we still
take the cgroup from 'current' because some of them work on the socket
that hasn't been properly initialized yet.
Behind the scenes, we allocate a shim program that is attached
to the trampoline and runs cgroup effective BPF programs array.
This shim has some rudimentary ref counting and can be shared
between several programs attaching to the same lsm hook from
different cgroups.
Note that this patch bloats cgroup size because we add 211
cgroup_bpf_attach_type(s) for simplicity sake. This will be
addressed in the subsequent patch.
Also note that we only add non-sleepable flavor for now. To enable
sleepable use-cases, bpf_prog_run_array_cg has to grab trace rcu,
shim programs have to be freed via trace rcu, cgroup_bpf.effective
should be also trace-rcu-managed + maybe some other changes that
I'm not aware of.
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220628174314.1216643-4-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
I'll be adding lsm cgroup specific helpers that grab
trampoline mutex.
No functional changes.
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220628174314.1216643-2-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Andrii Nakryiko says:
====================
This patch set removes all the deprecated APIs in preparation for 1.0 release.
It also makes libbpf_set_strict_mode() a no-op (but keeps it to let per-1.0
applications buildable and dynamically linkable against libbpf 1.0 if they
were already libbpf-1.0 ready) and starts enforcing all the
behaviors that were previously opt-in through libbpf_set_strict_mode().
xsk.{c,h} parts that are now properly provided by libxdp ([0]) are still used
by xdpxceiver.c in selftest/bpf, so I've moved xsk.{c,h} with barely any
changes to under selftests/bpf.
Other than that, apart from removing all the LIBBPF_DEPRECATED-marked APIs,
there is a bunch of internal clean ups allowed by that. I've also "restored"
libbpf.map inheritance chain while removing all the deprecated APIs. I think
that's the right way to do this, as applications using libbpf as shared
library but not relying on any deprecated APIs (i.e., "good citizens" that
prepared for libbpf 1.0 release ahead of time to minimize disruption) should
be able to link both against 0.x and 1.x versions. Either way, it doesn't seem
to break anything and preserve a history on when each "surviving" API was
added.
[0] https://github.com/xdp-project/xdp-tools/tree/master/lib/libxdp
v1->v2:
- rebase on latest bpf-next now that Jiri's perf patches landed;
- fix xsk.o dependency in Makefile to ensure libbpf headers are installed
reliably.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Seems like we missed to add 2 APIs to libbpf.map and another API was
misspelled. Fix it in libbpf.map.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-16-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Remove support for legacy features and behaviors that previously had to
be disabled by calling libbpf_set_strict_mode():
- legacy BPF map definitions are not supported now;
- RLIMIT_MEMLOCK auto-setting, if necessary, is always on (but see
libbpf_set_memlock_rlim());
- program name is used for program pinning (instead of section name);
- cleaned up error returning logic;
- entry BPF programs should have SEC() always.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-15-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Libbpf 1.0 stops support legacy-style BPF map definitions. Selftests has
been migrated away from using legacy BPF map definitions except for two
selftests, to make sure that legacy functionality still worked in
pre-1.0 libbpf. Now it's time to let those tests go as libbpf 1.0 is
imminent.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-14-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Clean up internals that had to deal with the possibility of
multi-instance bpf_programs. Libbpf 1.0 doesn't support this, so all
this is not necessary now and can be simplified.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-12-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Keep the LIBBPF_DEPRECATED_SINCE macro "framework" for future
deprecations, but clean up 0.x related helper macros.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-11-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Remove all the public APIs that are related to creating multi-instance
bpf_programs through custom preprocessing callback and generally working
with them.
Also remove all the bpf_{object,map,program}__[set_]priv() APIs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-10-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Remove a bunch of high-level bpf_object/bpf_map/bpf_program related
APIs. All the APIs related to private per-object/map/prog state,
program preprocessing callback, and generally everything multi-instance
related is removed in a separate patch.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-9-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Drop low-level APIs as well as high-level (and very confusingly named)
BPF object loading bpf_prog_load_xattr() and bpf_prog_load_deprecated()
APIs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Remove deprecated xsk APIs from libbpf. But given we have selftests
relying on this, move those files (with minimal adjustments to make them
compilable) under selftests/bpf.
We also remove all the removed APIs from libbpf.map, while overall
keeping version inheritance chain, as most APIs are backwards
compatible so there is no need to reassign them as LIBBPF_1.0.0 versions.
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
syzbot reproduced the bug ...
BUG: sleeping function called from invalid context at kernel/workqueue.c:3010
... with the following stack trace fragment ...
start_flush_work kernel/workqueue.c:3010 [inline]
__flush_work+0x109/0xb10 kernel/workqueue.c:3074
__cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3162
sk_psock_stop+0x4cb/0x630 net/core/skmsg.c:802
sock_map_destroy+0x333/0x760 net/core/sock_map.c:1581
inet_csk_destroy_sock+0x196/0x440 net/ipv4/inet_connection_sock.c:1130
__tcp_close+0xd5b/0x12b0 net/ipv4/tcp.c:2897
tcp_close+0x29/0xc0 net/ipv4/tcp.c:2909
... introduced by d8616ee2af. Do a quick trace of the code path and the
bug is obvious:
inet_csk_destroy_sock(sk)
sk_prot->destroy(sk); <--- sock_map_destroy
sk_psock_stop(, true); <--- true so cancel workqueue
cancel_work_sync() <--- splat, because *_bh_disable()
We can not call cancel_work_sync() from inside destroy path. So mark
the sk_psock_stop call to skip this cancel_work_sync(). This will avoid
the BUG, but means we may run sk_psock_backlog after or during the
destroy op. We zapped the ingress_skb queue in sk_psock_stop (safe to
do with local_bh_disable) so its empty and the sk_psock_backlog work
item will not find any pkts to process here. However, because we are
not going to wait for it or clear its ->state its possible it kicks off
or is already running. This should be 'safe' up until psock drops its
refcnt to psock->sk. The sock_put() that drops this reference is only
done at psock destroy time from sk_psock_destroy(). This is done through
workqueue when sk_psock_drop() is called on psock refnt reaches 0.
And importantly sk_psock_destroy() does a cancel_work_sync(). So trivial
fix works.
I've had hit or miss luck reproducing this caught it once or twice with
the provided reproducer when running with many runners. However, syzkaller
is very good at reproducing so relying on syzkaller to verify fix.
Fixes: d8616ee2af ("bpf, sockmap: Fix sk->sk_forward_alloc warn_on in sk_stream_kill_queues")
Reported-by: syzbot+140186ceba0c496183bc@syzkaller.appspotmail.com
Suggested-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Yufen <wangyufen@huawei.com>
Link: https://lore.kernel.org/bpf/20220628035803.317876-1-john.fastabend@gmail.com
BPF type compatibility checks (bpf_core_types_are_compat()) are
currently duplicated between kernel and user space. That's a historical
artifact more than intentional doing and can lead to subtle bugs where
one implementation is adjusted but another is forgotten.
That happened with the enum64 work, for example, where the libbpf side
was changed (commit 23b2a3a8f6 ("libbpf: Add enum64 relocation
support")) to use the btf_kind_core_compat() helper function but the
kernel side was not (commit 6089fb325c ("bpf: Add btf enum64
support")).
This patch addresses both the duplication issue, by merging both
implementations and moving them into relo_core.c, and fixes the alluded
to kind check (by giving preference to libbpf's already adjusted logic).
For discussion of the topic, please refer to:
https://lore.kernel.org/bpf/CAADnVQKbWR7oarBdewgOBZUPzryhRYvEbkhyPJQHHuxq=0K1gw@mail.gmail.com/T/#mcc99f4a33ad9a322afaf1b9276fb1f0b7add9665
Changelog:
v1 -> v2:
- limited libbpf recursion limit to 32
- changed name to __bpf_core_types_are_compat
- included warning previously present in libbpf version
- merged kernel and user space changes into a single patch
Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220623182934.2582827-1-deso@posteo.net
Jiri Olsa says:
====================
hi,
sending change we discussed some time ago [1] to get rid of
some deprecated functions we use in perf prologue code.
Despite the gloomy discussion I think the final code does
not look that bad ;-)
This patchset removes following libbpf functions from perf:
bpf_program__set_prep
bpf_program__nth_fd
struct bpf_prog_prep_result
v5 changes:
- squashed patches together so we don't break bisection [Arnaldo]
v4 changes:
- fix typo [Andrii]
v3 changes:
- removed R0/R1 zero init in libbpf_prog_prepare_load_fn,
because it's not needed [Andrii]
- rebased/post on top of bpf-next/master which now has
all the needed perf/core changes
v2 changes:
- use fallback section prog handler, so we don't need to
use section prefix [Andrii]
- realloc prog->insns array in bpf_program__set_insns [Andrii]
- squash patch 1 from previous version with
bpf_program__set_insns change [Daniel]
- patch 3 already merged [Arnaldo]
- added more comments
thanks,
jirka
[1] https://lore.kernel.org/bpf/CAEf4BzaiBO3_617kkXZdYJ8hS8YF--ZLgapNbgeeEJ-pY0H88g@mail.gmail.com/
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Some functions we use for bpf prologue generation are going to be
deprecated. This change reworks current code not to use them.
We need to replace following functions/struct:
bpf_program__set_prep
bpf_program__nth_fd
struct bpf_prog_prep_result
Currently we use bpf_program__set_prep to hook perf callback before
program is loaded and provide new instructions with the prologue.
We replace this function/ality by taking instructions for specific
program, attaching prologue to them and load such new ebpf programs
with prologue using separate bpf_prog_load calls (outside libbpf
load machinery).
Before we can take and use program instructions, we need libbpf to
actually load it. This way we get the final shape of its instructions
with all relocations and verifier adjustments).
There's one glitch though.. perf kprobe program already assumes
generated prologue code with proper values in argument registers,
so loading such program directly will fail in the verifier.
That's where the fallback pre-load handler fits in and prepends
the initialization code to the program. Once such program is loaded
we take its instructions, cut off the initialization code and prepend
the prologue.
I know.. sorry ;-)
To have access to the program when loading this patch adds support to
register 'fallback' section handler to take care of perf kprobe programs.
The fallback means that it handles any section definition besides the
ones that libbpf handles.
The handler serves two purposes:
- allows perf programs to have special arguments in section name
- allows perf to use pre-load callback where we can attach init
code (zeroing all argument registers) to each perf program
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/bpf/20220616202214.70359-2-jolsa@kernel.org
This test verifies that bpf_loop() inlining works as expected when
address of `env->prog` is updated. This address is updated upon BPF
program reallocation.
Reallocation is handled by bpf_prog_realloc(), which reuses old memory
if page boundary is not crossed. The value of `len` in the test is
chosen to cross this boundary on bpf_loop() patching.
Verify that the use-after-free bug in inline_bpf_loop() reported by
Dan Carpenter is fixed.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220624020613.548108-3-eddyz87@gmail.com
As reported by Dan Carpenter, the following statements in inline_bpf_loop()
might cause a use-after-free bug:
struct bpf_prog *new_prog;
// ...
new_prog = bpf_patch_insn_data(env, position, insn_buf, *cnt);
// ...
env->prog->insnsi[call_insn_offset].imm = callback_offset;
The bpf_patch_insn_data() might free the memory used by env->prog.
Fixes: 1ade237119 ("bpf: Inline calls to bpf_loop when callback is known")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220624020613.548108-2-eddyz87@gmail.com
test_sock_fields__detach() got called with a null pointer here when one
of the CHECKs or ASSERTs up to the test_sock_fields__open_and_load()
call resulted in a jump to the "done" label.
A skeletons *__detach() is not safe to call with a null pointer, though.
This led to a segfault.
Go the easy route and only call test_sock_fields__destroy() which is
null-pointer safe and includes detaching.
Came across this while looking[1] to introduce the usage of
bpf_tcp_helpers.h (included in progs/test_sock_fields.c) together with
vmlinux.h.
[1] https://lore.kernel.org/bpf/629bc069dd807d7ac646f836e9dca28bbc1108e2.camel@mailbox.tu-berlin.de/
Fixes: 8f50f16ff3 ("selftests/bpf: Extend verifier and bpf_sock tests for dst_port loads")
Signed-off-by: Jörn-Thorben Hinz <jthinz@mailbox.tu-berlin.de>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220621070116.307221-1-jthinz@mailbox.tu-berlin.de
Jörn-Thorben Hinz says:
====================
This series corrects some inconveniences for a BPF TCP CC that
implements and uses tcp_congestion_ops.cong_control(). Until now, such a
CC did not have all necessary write access to struct sock and
unnecessarily needed to implement cong_avoid().
v4:
- Remove braces around single statements after if
- Don’t check pointer passed to bpf_link__destroy()
v3:
- Add a selftest writing sk_pacing_*
- Add a selftest with incomplete tcp_congestion_ops
- Add a selftest with unsupported get_info()
- Remove an unused variable
- Reword a comment about reg() in bpf_struct_ops_map_update_elem()
v2:
- Drop redundant check for required functions and just rely on
tcp_register_congestion_control() (Martin KaFai Lau)
====================
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Test whether a TCP CC implemented in BPF providing get_info() is
rejected correctly. get_info() is unsupported in a BPF CC. The check for
required functions in a BPF CC has moved, this test ensures unsupported
functions are still rejected correctly.
Signed-off-by: Jörn-Thorben Hinz <jthinz@mailbox.tu-berlin.de>
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220622191227.898118-6-jthinz@mailbox.tu-berlin.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Test whether a TCP CC implemented in BPF providing neither cong_avoid()
nor cong_control() is correctly rejected. This check solely depends on
tcp_register_congestion_control() now, which is invoked during
bpf_map__attach_struct_ops().
Signed-off-by: Jörn-Thorben Hinz <jthinz@mailbox.tu-berlin.de>
Link: https://lore.kernel.org/r/20220622191227.898118-5-jthinz@mailbox.tu-berlin.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Test whether a TCP CC implemented in BPF is allowed to write
sk_pacing_rate and sk_pacing_status in struct sock. This is needed when
cong_control() is implemented and used.
Signed-off-by: Jörn-Thorben Hinz <jthinz@mailbox.tu-berlin.de>
Link: https://lore.kernel.org/r/20220622191227.898118-4-jthinz@mailbox.tu-berlin.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Remove the check for required and optional functions in a struct
tcp_congestion_ops from bpf_tcp_ca.c. Rely on
tcp_register_congestion_control() to reject a BPF CC that does not
implement all required functions, as it will do for a non-BPF CC.
When a CC implements tcp_congestion_ops.cong_control(), the alternate
cong_avoid() is not in use in the TCP stack. Previously, a BPF CC was
still forced to implement cong_avoid() as a no-op since it was
non-optional in bpf_tcp_ca.c.
Signed-off-by: Jörn-Thorben Hinz <jthinz@mailbox.tu-berlin.de>
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220622191227.898118-3-jthinz@mailbox.tu-berlin.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A CC that implements tcp_congestion_ops.cong_control() should be able to
control sk_pacing_rate and set sk_pacing_status, since
tcp_update_pacing_rate() is never called in this case. A built-in CC or
one from a kernel module is already able to write to both struct sock
members. For a BPF program, write access has not been allowed, yet.
Signed-off-by: Jörn-Thorben Hinz <jthinz@mailbox.tu-berlin.de>
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220622191227.898118-2-jthinz@mailbox.tu-berlin.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The prototype of .features is netdev_features_t, it should use
NETIF_F_LLTX and NETIF_F_HW_VLAN_STAG_TX, not NETIF_F_LLTX_BIT
and NETIF_F_HW_VLAN_STAG_TX_BIT.
Fixes: cf204a7183 ("bpf, testing: Introduce 'gso_linear_no_head_frag' skb_segment test")
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20220622135002.8263-1-shenjian15@huawei.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a benchmarks to demonstrate the performance cliff for local_storage
get as the number of local_storage maps increases beyond current
local_storage implementation's cache size.
"sequential get" and "interleaved get" benchmarks are added, both of
which do many bpf_task_storage_get calls on sets of task local_storage
maps of various counts, while considering a single specific map to be
'important' and counting task_storage_gets to the important map
separately in addition to normal 'hits' count of all gets. Goal here is
to mimic scenario where a particular program using one map - the
important one - is running on a system where many other local_storage
maps exist and are accessed often.
While "sequential get" benchmark does bpf_task_storage_get for map 0, 1,
..., {9, 99, 999} in order, "interleaved" benchmark interleaves 4
bpf_task_storage_gets for the important map for every 10 map gets. This
is meant to highlight performance differences when important map is
accessed far more frequently than non-important maps.
A "hashmap control" benchmark is also included for easy comparison of
standard bpf hashmap lookup vs local_storage get. The benchmark is
similar to "sequential get", but creates and uses BPF_MAP_TYPE_HASH
instead of local storage. Only one inner map is created - a hashmap
meant to hold tid -> data mapping for all tasks. Size of the hashmap is
hardcoded to my system's PID_MAX_LIMIT (4,194,304). The number of these
keys which are actually fetched as part of the benchmark is
configurable.
Addition of this benchmark is inspired by conversation with Alexei in a
previous patchset's thread [0], which highlighted the need for such a
benchmark to motivate and validate improvements to local_storage
implementation. My approach in that series focused on improving
performance for explicitly-marked 'important' maps and was rejected
with feedback to make more generally-applicable improvements while
avoiding explicitly marking maps as important. Thus the benchmark
reports both general and important-map-focused metrics, so effect of
future work on both is clear.
Regarding the benchmark results. On a powerful system (Skylake, 20
cores, 256gb ram):
Hashmap Control
===============
num keys: 10
hashmap (control) sequential get: hits throughput: 20.900 ± 0.334 M ops/s, hits latency: 47.847 ns/op, important_hits throughput: 20.900 ± 0.334 M ops/s
num keys: 1000
hashmap (control) sequential get: hits throughput: 13.758 ± 0.219 M ops/s, hits latency: 72.683 ns/op, important_hits throughput: 13.758 ± 0.219 M ops/s
num keys: 10000
hashmap (control) sequential get: hits throughput: 6.995 ± 0.034 M ops/s, hits latency: 142.959 ns/op, important_hits throughput: 6.995 ± 0.034 M ops/s
num keys: 100000
hashmap (control) sequential get: hits throughput: 4.452 ± 0.371 M ops/s, hits latency: 224.635 ns/op, important_hits throughput: 4.452 ± 0.371 M ops/s
num keys: 4194304
hashmap (control) sequential get: hits throughput: 3.043 ± 0.033 M ops/s, hits latency: 328.587 ns/op, important_hits throughput: 3.043 ± 0.033 M ops/s
Local Storage
=============
num_maps: 1
local_storage cache sequential get: hits throughput: 47.298 ± 0.180 M ops/s, hits latency: 21.142 ns/op, important_hits throughput: 47.298 ± 0.180 M ops/s
local_storage cache interleaved get: hits throughput: 55.277 ± 0.888 M ops/s, hits latency: 18.091 ns/op, important_hits throughput: 55.277 ± 0.888 M ops/s
num_maps: 10
local_storage cache sequential get: hits throughput: 40.240 ± 0.802 M ops/s, hits latency: 24.851 ns/op, important_hits throughput: 4.024 ± 0.080 M ops/s
local_storage cache interleaved get: hits throughput: 48.701 ± 0.722 M ops/s, hits latency: 20.533 ns/op, important_hits throughput: 17.393 ± 0.258 M ops/s
num_maps: 16
local_storage cache sequential get: hits throughput: 44.515 ± 0.708 M ops/s, hits latency: 22.464 ns/op, important_hits throughput: 2.782 ± 0.044 M ops/s
local_storage cache interleaved get: hits throughput: 49.553 ± 2.260 M ops/s, hits latency: 20.181 ns/op, important_hits throughput: 15.767 ± 0.719 M ops/s
num_maps: 17
local_storage cache sequential get: hits throughput: 38.778 ± 0.302 M ops/s, hits latency: 25.788 ns/op, important_hits throughput: 2.284 ± 0.018 M ops/s
local_storage cache interleaved get: hits throughput: 43.848 ± 1.023 M ops/s, hits latency: 22.806 ns/op, important_hits throughput: 13.349 ± 0.311 M ops/s
num_maps: 24
local_storage cache sequential get: hits throughput: 19.317 ± 0.568 M ops/s, hits latency: 51.769 ns/op, important_hits throughput: 0.806 ± 0.024 M ops/s
local_storage cache interleaved get: hits throughput: 24.397 ± 0.272 M ops/s, hits latency: 40.989 ns/op, important_hits throughput: 6.863 ± 0.077 M ops/s
num_maps: 32
local_storage cache sequential get: hits throughput: 13.333 ± 0.135 M ops/s, hits latency: 75.000 ns/op, important_hits throughput: 0.417 ± 0.004 M ops/s
local_storage cache interleaved get: hits throughput: 16.898 ± 0.383 M ops/s, hits latency: 59.178 ns/op, important_hits throughput: 4.717 ± 0.107 M ops/s
num_maps: 100
local_storage cache sequential get: hits throughput: 6.360 ± 0.107 M ops/s, hits latency: 157.233 ns/op, important_hits throughput: 0.064 ± 0.001 M ops/s
local_storage cache interleaved get: hits throughput: 7.303 ± 0.362 M ops/s, hits latency: 136.930 ns/op, important_hits throughput: 1.907 ± 0.094 M ops/s
num_maps: 1000
local_storage cache sequential get: hits throughput: 0.452 ± 0.010 M ops/s, hits latency: 2214.022 ns/op, important_hits throughput: 0.000 ± 0.000 M ops/s
local_storage cache interleaved get: hits throughput: 0.542 ± 0.007 M ops/s, hits latency: 1843.341 ns/op, important_hits throughput: 0.136 ± 0.002 M ops/s
Looking at the "sequential get" results, it's clear that as the
number of task local_storage maps grows beyond the current cache size
(16), there's a significant reduction in hits throughput. Note that
current local_storage implementation assigns a cache_idx to maps as they
are created. Since "sequential get" is creating maps 0..n in order and
then doing bpf_task_storage_get calls in the same order, the benchmark
is effectively ensuring that a map will not be in cache when the program
tries to access it.
For "interleaved get" results, important-map hits throughput is greatly
increased as the important map is more likely to be in cache by virtue
of being accessed far more frequently. Throughput still reduces as #
maps increases, though.
To get a sense of the overhead of the benchmark program, I
commented out bpf_task_storage_get/bpf_map_lookup_elem in
local_storage_bench.c and ran the benchmark on the same host as the
'real' run. Results:
Hashmap Control
===============
num keys: 10
hashmap (control) sequential get: hits throughput: 54.288 ± 0.655 M ops/s, hits latency: 18.420 ns/op, important_hits throughput: 54.288 ± 0.655 M ops/s
num keys: 1000
hashmap (control) sequential get: hits throughput: 52.913 ± 0.519 M ops/s, hits latency: 18.899 ns/op, important_hits throughput: 52.913 ± 0.519 M ops/s
num keys: 10000
hashmap (control) sequential get: hits throughput: 53.480 ± 1.235 M ops/s, hits latency: 18.699 ns/op, important_hits throughput: 53.480 ± 1.235 M ops/s
num keys: 100000
hashmap (control) sequential get: hits throughput: 54.982 ± 1.902 M ops/s, hits latency: 18.188 ns/op, important_hits throughput: 54.982 ± 1.902 M ops/s
num keys: 4194304
hashmap (control) sequential get: hits throughput: 50.858 ± 0.707 M ops/s, hits latency: 19.662 ns/op, important_hits throughput: 50.858 ± 0.707 M ops/s
Local Storage
=============
num_maps: 1
local_storage cache sequential get: hits throughput: 110.990 ± 4.828 M ops/s, hits latency: 9.010 ns/op, important_hits throughput: 110.990 ± 4.828 M ops/s
local_storage cache interleaved get: hits throughput: 161.057 ± 4.090 M ops/s, hits latency: 6.209 ns/op, important_hits throughput: 161.057 ± 4.090 M ops/s
num_maps: 10
local_storage cache sequential get: hits throughput: 112.930 ± 1.079 M ops/s, hits latency: 8.855 ns/op, important_hits throughput: 11.293 ± 0.108 M ops/s
local_storage cache interleaved get: hits throughput: 115.841 ± 2.088 M ops/s, hits latency: 8.633 ns/op, important_hits throughput: 41.372 ± 0.746 M ops/s
num_maps: 16
local_storage cache sequential get: hits throughput: 115.653 ± 0.416 M ops/s, hits latency: 8.647 ns/op, important_hits throughput: 7.228 ± 0.026 M ops/s
local_storage cache interleaved get: hits throughput: 138.717 ± 1.649 M ops/s, hits latency: 7.209 ns/op, important_hits throughput: 44.137 ± 0.525 M ops/s
num_maps: 17
local_storage cache sequential get: hits throughput: 112.020 ± 1.649 M ops/s, hits latency: 8.927 ns/op, important_hits throughput: 6.598 ± 0.097 M ops/s
local_storage cache interleaved get: hits throughput: 128.089 ± 1.960 M ops/s, hits latency: 7.807 ns/op, important_hits throughput: 38.995 ± 0.597 M ops/s
num_maps: 24
local_storage cache sequential get: hits throughput: 92.447 ± 5.170 M ops/s, hits latency: 10.817 ns/op, important_hits throughput: 3.855 ± 0.216 M ops/s
local_storage cache interleaved get: hits throughput: 128.844 ± 2.808 M ops/s, hits latency: 7.761 ns/op, important_hits throughput: 36.245 ± 0.790 M ops/s
num_maps: 32
local_storage cache sequential get: hits throughput: 102.042 ± 1.462 M ops/s, hits latency: 9.800 ns/op, important_hits throughput: 3.194 ± 0.046 M ops/s
local_storage cache interleaved get: hits throughput: 126.577 ± 1.818 M ops/s, hits latency: 7.900 ns/op, important_hits throughput: 35.332 ± 0.507 M ops/s
num_maps: 100
local_storage cache sequential get: hits throughput: 111.327 ± 1.401 M ops/s, hits latency: 8.983 ns/op, important_hits throughput: 1.113 ± 0.014 M ops/s
local_storage cache interleaved get: hits throughput: 131.327 ± 1.339 M ops/s, hits latency: 7.615 ns/op, important_hits throughput: 34.302 ± 0.350 M ops/s
num_maps: 1000
local_storage cache sequential get: hits throughput: 101.978 ± 0.563 M ops/s, hits latency: 9.806 ns/op, important_hits throughput: 0.102 ± 0.001 M ops/s
local_storage cache interleaved get: hits throughput: 141.084 ± 1.098 M ops/s, hits latency: 7.088 ns/op, important_hits throughput: 35.430 ± 0.276 M ops/s
Adjusting for overhead, latency numbers for "hashmap control" and
"sequential get" are:
hashmap_control_1k: ~53.8ns
hashmap_control_10k: ~124.2ns
hashmap_control_100k: ~206.5ns
sequential_get_1: ~12.1ns
sequential_get_10: ~16.0ns
sequential_get_16: ~13.8ns
sequential_get_17: ~16.8ns
sequential_get_24: ~40.9ns
sequential_get_32: ~65.2ns
sequential_get_100: ~148.2ns
sequential_get_1000: ~2204ns
Clearly demonstrating a cliff.
In the discussion for v1 of this patch, Alexei noted that local_storage
was 2.5x faster than a large hashmap when initially implemented [1]. The
benchmark results show that local_storage is 5-10x faster: a
long-running BPF application putting some pid-specific info into a
hashmap for each pid it sees will probably see on the order of 10-100k
pids. Bench numbers for hashmaps of this size are ~10x slower than
sequential_get_16, but as the number of local_storage maps grows far
past local_storage cache size the performance advantage shrinks and
eventually reverses.
When running the benchmarks it may be necessary to bump 'open files'
ulimit for a successful run.
[0]: https://lore.kernel.org/all/20220420002143.1096548-1-davemarchevsky@fb.com
[1]: https://lore.kernel.org/bpf/20220511173305.ftldpn23m4ski3d3@MBP-98dd607d3435.dhcp.thefacebook.com/
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20220620222554.270578-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This changes the section name for the bpf program embedded in these
files to "xdp.frags" to allow the programs to be loaded on drivers that
are using an MTU greater than PAGE_SIZE. Rather than directly accessing
the buffers, the packet data is now accessed via xdp helper functions to
provide an example for those who may need to write more complex
programs.
v2: remove new unnecessary variable
Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/20220621175402.35327-1-gospo@broadcom.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The BPF core/verifier is hard-coded to permit mixing bpf2bpf and tail
calls for only x86-64. Change the logic to instead rely on a new weak
function 'bool bpf_jit_supports_subprog_tailcalls(void)', which a capable
JIT backend can override.
Update the x86-64 eBPF JIT to reflect this.
Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
[jakub: drop MIPS bits and tweak patch subject]
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220617105735.733938-2-jakub@cloudflare.com
