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  1. 03 6月, 2020 2 次提交
  3. 02 6月, 2020 6 次提交
    • J
      bpf: Add link-based BPF program attachment to network namespace · 7f045a49
      由 Jakub Sitnicki 提交于 
      Extend bpf() syscall subcommands that operate on bpf_link, that is
LINK_CREATE, LINK_UPDATE, OBJ_GET_INFO, to accept attach types tied to
network namespaces (only flow dissector at the moment).

Link-based and prog-based attachment can be used interchangeably, but only
one can exist at a time. Attempts to attach a link when a prog is already
attached directly, and the other way around, will be met with -EEXIST.
Attempts to detach a program when link exists result in -EINVAL.

Attachment of multiple links of same attach type to one netns is not
supported with the intention to lift the restriction when a use-case
presents itself. Because of that link create returns -E2BIG when trying to
create another netns link, when one already exists.

Link-based attachments to netns don't keep a netns alive by holding a ref
to it. Instead links get auto-detached from netns when the latter is being
destroyed, using a pernet pre_exit callback.

When auto-detached, link lives in defunct state as long there are open FDs
for it. -ENOLINK is returned if a user tries to update a defunct link.

Because bpf_link to netns doesn't hold a ref to struct net, special care is
taken when releasing, updating, or filling link info. The netns might be
getting torn down when any of these link operations are in progress. That
is why auto-detach and update/release/fill_info are synchronized by the
same mutex. Also, link ops have to always check if auto-detach has not
happened yet and if netns is still alive (refcnt > 0).
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200531082846.2117903-5-jakub@cloudflare.com
      7f045a49
    • A
      tools/bpf: sync bpf.h · df8fe57c
      由 Alexei Starovoitov 提交于 
      Sync bpf.h into tool/include/uapi/
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      df8fe57c
    • D
      xdp: Add xdp_txq_info to xdp_buff · 64b59025
      由 David Ahern 提交于 
      Add xdp_txq_info as the Tx counterpart to xdp_rxq_info. At the
moment only the device is added. Other fields (queue_index)
can be added as use cases arise.

>From a UAPI perspective, add egress_ifindex to xdp context for
bpf programs to see the Tx device.

Update the verifier to only allow accesses to egress_ifindex by
XDP programs with BPF_XDP_DEVMAP expected attach type.
Signed-off-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200529220716.75383-4-dsahern@kernel.orgSigned-off-by: NAlexei Starovoitov <ast@kernel.org>
      64b59025
    • D
      bpf: Add support to attach bpf program to a devmap entry · fbee97fe
      由 David Ahern 提交于 
      Add BPF_XDP_DEVMAP attach type for use with programs associated with a
DEVMAP entry.

Allow DEVMAPs to associate a program with a device entry by adding
a bpf_prog.fd to 'struct bpf_devmap_val'. Values read show the program
id, so the fd and id are a union. bpf programs can get access to the
struct via vmlinux.h.

The program associated with the fd must have type XDP with expected
attach type BPF_XDP_DEVMAP. When a program is associated with a device
index, the program is run on an XDP_REDIRECT and before the buffer is
added to the per-cpu queue. At this point rxq data is still valid; the
next patch adds tx device information allowing the prorgam to see both
ingress and egress device indices.

XDP generic is skb based and XDP programs do not work with skb's. Block
the use case by walking maps used by a program that is to be attached
via xdpgeneric and fail if any of them are DEVMAP / DEVMAP_HASH with

Block attach of BPF_XDP_DEVMAP programs to devices.
Signed-off-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200529220716.75383-3-dsahern@kernel.orgSigned-off-by: NAlexei Starovoitov <ast@kernel.org>
      fbee97fe
    • A
      bpf: Implement BPF ring buffer and verifier support for it · 457f4436
      由 Andrii Nakryiko 提交于 
      This commit adds a new MPSC ring buffer implementation into BPF ecosystem,
which allows multiple CPUs to submit data to a single shared ring buffer. On
the consumption side, only single consumer is assumed.

Motivation
----------
There are two distinctive motivators for this work, which are not satisfied by
existing perf buffer, which prompted creation of a new ring buffer
implementation.
  - more efficient memory utilization by sharing ring buffer across CPUs;
  - preserving ordering of events that happen sequentially in time, even
  across multiple CPUs (e.g., fork/exec/exit events for a task).

These two problems are independent, but perf buffer fails to satisfy both.
Both are a result of a choice to have per-CPU perf ring buffer.  Both can be
also solved by having an MPSC implementation of ring buffer. The ordering
problem could technically be solved for perf buffer with some in-kernel
counting, but given the first one requires an MPSC buffer, the same solution
would solve the second problem automatically.

Semantics and APIs
------------------
Single ring buffer is presented to BPF programs as an instance of BPF map of
type BPF_MAP_TYPE_RINGBUF. Two other alternatives considered, but ultimately
rejected.

One way would be to, similar to BPF_MAP_TYPE_PERF_EVENT_ARRAY, make
BPF_MAP_TYPE_RINGBUF could represent an array of ring buffers, but not enforce
"same CPU only" rule. This would be more familiar interface compatible with
existing perf buffer use in BPF, but would fail if application needed more
advanced logic to lookup ring buffer by arbitrary key. HASH_OF_MAPS addresses
this with current approach. Additionally, given the performance of BPF
ringbuf, many use cases would just opt into a simple single ring buffer shared
among all CPUs, for which current approach would be an overkill.

Another approach could introduce a new concept, alongside BPF map, to
represent generic "container" object, which doesn't necessarily have key/value
interface with lookup/update/delete operations. This approach would add a lot
of extra infrastructure that has to be built for observability and verifier
support. It would also add another concept that BPF developers would have to
familiarize themselves with, new syntax in libbpf, etc. But then would really
provide no additional benefits over the approach of using a map.
BPF_MAP_TYPE_RINGBUF doesn't support lookup/update/delete operations, but so
doesn't few other map types (e.g., queue and stack; array doesn't support
delete, etc).

The approach chosen has an advantage of re-using existing BPF map
infrastructure (introspection APIs in kernel, libbpf support, etc), being
familiar concept (no need to teach users a new type of object in BPF program),
and utilizing existing tooling (bpftool). For common scenario of using
a single ring buffer for all CPUs, it's as simple and straightforward, as
would be with a dedicated "container" object. On the other hand, by being
a map, it can be combined with ARRAY_OF_MAPS and HASH_OF_MAPS map-in-maps to
implement a wide variety of topologies, from one ring buffer for each CPU
(e.g., as a replacement for perf buffer use cases), to a complicated
application hashing/sharding of ring buffers (e.g., having a small pool of
ring buffers with hashed task's tgid being a look up key to preserve order,
but reduce contention).

Key and value sizes are enforced to be zero. max_entries is used to specify
the size of ring buffer and has to be a power of 2 value.

There are a bunch of similarities between perf buffer
(BPF_MAP_TYPE_PERF_EVENT_ARRAY) and new BPF ring buffer semantics:
  - variable-length records;
  - if there is no more space left in ring buffer, reservation fails, no
    blocking;
  - memory-mappable data area for user-space applications for ease of
    consumption and high performance;
  - epoll notifications for new incoming data;
  - but still the ability to do busy polling for new data to achieve the
    lowest latency, if necessary.

BPF ringbuf provides two sets of APIs to BPF programs:
  - bpf_ringbuf_output() allows to *copy* data from one place to a ring
    buffer, similarly to bpf_perf_event_output();
  - bpf_ringbuf_reserve()/bpf_ringbuf_commit()/bpf_ringbuf_discard() APIs
    split the whole process into two steps. First, a fixed amount of space is
    reserved. If successful, a pointer to a data inside ring buffer data area
    is returned, which BPF programs can use similarly to a data inside
    array/hash maps. Once ready, this piece of memory is either committed or
    discarded. Discard is similar to commit, but makes consumer ignore the
    record.

bpf_ringbuf_output() has disadvantage of incurring extra memory copy, because
record has to be prepared in some other place first. But it allows to submit
records of the length that's not known to verifier beforehand. It also closely
matches bpf_perf_event_output(), so will simplify migration significantly.

bpf_ringbuf_reserve() avoids the extra copy of memory by providing a memory
pointer directly to ring buffer memory. In a lot of cases records are larger
than BPF stack space allows, so many programs have use extra per-CPU array as
a temporary heap for preparing sample. bpf_ringbuf_reserve() avoid this needs
completely. But in exchange, it only allows a known constant size of memory to
be reserved, such that verifier can verify that BPF program can't access
memory outside its reserved record space. bpf_ringbuf_output(), while slightly
slower due to extra memory copy, covers some use cases that are not suitable
for bpf_ringbuf_reserve().

The difference between commit and discard is very small. Discard just marks
a record as discarded, and such records are supposed to be ignored by consumer
code. Discard is useful for some advanced use-cases, such as ensuring
all-or-nothing multi-record submission, or emulating temporary malloc()/free()
within single BPF program invocation.

Each reserved record is tracked by verifier through existing
reference-tracking logic, similar to socket ref-tracking. It is thus
impossible to reserve a record, but forget to submit (or discard) it.

bpf_ringbuf_query() helper allows to query various properties of ring buffer.
Currently 4 are supported:
  - BPF_RB_AVAIL_DATA returns amount of unconsumed data in ring buffer;
  - BPF_RB_RING_SIZE returns the size of ring buffer;
  - BPF_RB_CONS_POS/BPF_RB_PROD_POS returns current logical possition of
    consumer/producer, respectively.
Returned values are momentarily snapshots of ring buffer state and could be
off by the time helper returns, so this should be used only for
debugging/reporting reasons or for implementing various heuristics, that take
into account highly-changeable nature of some of those characteristics.

One such heuristic might involve more fine-grained control over poll/epoll
notifications about new data availability in ring buffer. Together with
BPF_RB_NO_WAKEUP/BPF_RB_FORCE_WAKEUP flags for output/commit/discard helpers,
it allows BPF program a high degree of control and, e.g., more efficient
batched notifications. Default self-balancing strategy, though, should be
adequate for most applications and will work reliable and efficiently already.

Design and implementation
-------------------------
This reserve/commit schema allows a natural way for multiple producers, either
on different CPUs or even on the same CPU/in the same BPF program, to reserve
independent records and work with them without blocking other producers. This
means that if BPF program was interruped by another BPF program sharing the
same ring buffer, they will both get a record reserved (provided there is
enough space left) and can work with it and submit it independently. This
applies to NMI context as well, except that due to using a spinlock during
reservation, in NMI context, bpf_ringbuf_reserve() might fail to get a lock,
in which case reservation will fail even if ring buffer is not full.

The ring buffer itself internally is implemented as a power-of-2 sized
circular buffer, with two logical and ever-increasing counters (which might
wrap around on 32-bit architectures, that's not a problem):
  - consumer counter shows up to which logical position consumer consumed the
    data;
  - producer counter denotes amount of data reserved by all producers.

Each time a record is reserved, producer that "owns" the record will
successfully advance producer counter. At that point, data is still not yet
ready to be consumed, though. Each record has 8 byte header, which contains
the length of reserved record, as well as two extra bits: busy bit to denote
that record is still being worked on, and discard bit, which might be set at
commit time if record is discarded. In the latter case, consumer is supposed
to skip the record and move on to the next one. Record header also encodes
record's relative offset from the beginning of ring buffer data area (in
pages). This allows bpf_ringbuf_commit()/bpf_ringbuf_discard() to accept only
the pointer to the record itself, without requiring also the pointer to ring
buffer itself. Ring buffer memory location will be restored from record
metadata header. This significantly simplifies verifier, as well as improving
API usability.

Producer counter increments are serialized under spinlock, so there is
a strict ordering between reservations. Commits, on the other hand, are
completely lockless and independent. All records become available to consumer
in the order of reservations, but only after all previous records where
already committed. It is thus possible for slow producers to temporarily hold
off submitted records, that were reserved later.

Reservation/commit/consumer protocol is verified by litmus tests in
Documentation/litmus-test/bpf-rb.

One interesting implementation bit, that significantly simplifies (and thus
speeds up as well) implementation of both producers and consumers is how data
area is mapped twice contiguously back-to-back in the virtual memory. This
allows to not take any special measures for samples that have to wrap around
at the end of the circular buffer data area, because the next page after the
last data page would be first data page again, and thus the sample will still
appear completely contiguous in virtual memory. See comment and a simple ASCII
diagram showing this visually in bpf_ringbuf_area_alloc().

Another feature that distinguishes BPF ringbuf from perf ring buffer is
a self-pacing notifications of new data being availability.
bpf_ringbuf_commit() implementation will send a notification of new record
being available after commit only if consumer has already caught up right up
to the record being committed. If not, consumer still has to catch up and thus
will see new data anyways without needing an extra poll notification.
Benchmarks (see tools/testing/selftests/bpf/benchs/bench_ringbuf.c) show that
this allows to achieve a very high throughput without having to resort to
tricks like "notify only every Nth sample", which are necessary with perf
buffer. For extreme cases, when BPF program wants more manual control of
notifications, commit/discard/output helpers accept BPF_RB_NO_WAKEUP and
BPF_RB_FORCE_WAKEUP flags, which give full control over notifications of data
availability, but require extra caution and diligence in using this API.

Comparison to alternatives
--------------------------
Before considering implementing BPF ring buffer from scratch existing
alternatives in kernel were evaluated, but didn't seem to meet the needs. They
largely fell into few categores:
  - per-CPU buffers (perf, ftrace, etc), which don't satisfy two motivations
    outlined above (ordering and memory consumption);
  - linked list-based implementations; while some were multi-producer designs,
    consuming these from user-space would be very complicated and most
    probably not performant; memory-mapping contiguous piece of memory is
    simpler and more performant for user-space consumers;
  - io_uring is SPSC, but also requires fixed-sized elements. Naively turning
    SPSC queue into MPSC w/ lock would have subpar performance compared to
    locked reserve + lockless commit, as with BPF ring buffer. Fixed sized
    elements would be too limiting for BPF programs, given existing BPF
    programs heavily rely on variable-sized perf buffer already;
  - specialized implementations (like a new printk ring buffer, [0]) with lots
    of printk-specific limitations and implications, that didn't seem to fit
    well for intended use with BPF programs.

  [0] https://lwn.net/Articles/779550/Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200529075424.3139988-2-andriin@fb.comSigned-off-by: NAlexei Starovoitov <ast@kernel.org>
      457f4436
    • J
      bpf, sk_msg: Add get socket storage helpers · 13d70f5a
      由 John Fastabend 提交于 
      Add helpers to use local socket storage.
Signed-off-by: NJohn Fastabend <john.fastabend@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/159033907577.12355.14740125020572756560.stgit@john-Precision-5820-TowerSigned-off-by: NAlexei Starovoitov <ast@kernel.org>
      13d70f5a
  5. 20 5月, 2020 2 次提交
    • A
      tools/bpf: sync bpf.h · fb53d3b6
      由 Alexei Starovoitov 提交于 
      Sync tools/include/uapi/linux/bpf.h from include/uapi.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      fb53d3b6
    • D
      bpf: Add get{peer, sock}name attach types for sock_addr · 1b66d253
      由 Daniel Borkmann 提交于 
      As stated in 983695fa ("bpf: fix unconnected udp hooks"), the objective
for the existing cgroup connect/sendmsg/recvmsg/bind BPF hooks is to be
transparent to applications. In Cilium we make use of these hooks [0] in
order to enable E-W load balancing for existing Kubernetes service types
for all Cilium managed nodes in the cluster. Those backends can be local
or remote. The main advantage of this approach is that it operates as close
as possible to the socket, and therefore allows to avoid packet-based NAT
given in connect/sendmsg/recvmsg hooks we only need to xlate sock addresses.

This also allows to expose NodePort services on loopback addresses in the
host namespace, for example. As another advantage, this also efficiently
blocks bind requests for applications in the host namespace for exposed
ports. However, one missing item is that we also need to perform reverse
xlation for inet{,6}_getname() hooks such that we can return the service
IP/port tuple back to the application instead of the remote peer address.

The vast majority of applications does not bother about getpeername(), but
in a few occasions we've seen breakage when validating the peer's address
since it returns unexpectedly the backend tuple instead of the service one.
Therefore, this trivial patch allows to customise and adds a getpeername()
as well as getsockname() BPF cgroup hook for both IPv4 and IPv6 in order
to address this situation.

Simple example:

  # ./cilium/cilium service list
  ID   Frontend     Service Type   Backend
  1    1.2.3.4:80   ClusterIP      1 => 10.0.0.10:80

Before; curl's verbose output example, no getpeername() reverse xlation:

  # curl --verbose 1.2.3.4
  * Rebuilt URL to: 1.2.3.4/
  *   Trying 1.2.3.4...
  * TCP_NODELAY set
  * Connected to 1.2.3.4 (10.0.0.10) port 80 (#0)
  > GET / HTTP/1.1
  > Host: 1.2.3.4
  > User-Agent: curl/7.58.0
  > Accept: */*
  [...]

After; with getpeername() reverse xlation:

  # curl --verbose 1.2.3.4
  * Rebuilt URL to: 1.2.3.4/
  *   Trying 1.2.3.4...
  * TCP_NODELAY set
  * Connected to 1.2.3.4 (1.2.3.4) port 80 (#0)
  > GET / HTTP/1.1
  >  Host: 1.2.3.4
  > User-Agent: curl/7.58.0
  > Accept: */*
  [...]

Originally, I had both under a BPF_CGROUP_INET{4,6}_GETNAME type and exposed
peer to the context similar as in inet{,6}_getname() fashion, but API-wise
this is suboptimal as it always enforces programs having to test for ctx->peer
which can easily be missed, hence BPF_CGROUP_INET{4,6}_GET{PEER,SOCK}NAME split.
Similarly, the checked return code is on tnum_range(1, 1), but if a use case
comes up in future, it can easily be changed to return an error code instead.
Helper and ctx member access is the same as with connect/sendmsg/etc hooks.

  [0] https://github.com/cilium/cilium/blob/master/bpf/bpf_sock.cSigned-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Acked-by: NAndrey Ignatov <rdna@fb.com>
Link: https://lore.kernel.org/bpf/61a479d759b2482ae3efb45546490bacd796a220.1589841594.git.daniel@iogearbox.net
      1b66d253
  7. 15 5月, 2020 2 次提交
  9. 14 5月, 2020 1 次提交
    • M
      uapi: deprecate STATX_ALL · 581701b7
      由 Miklos Szeredi 提交于 
      Constants of the *_ALL type can be actively harmful due to the fact that
developers will usually fail to consider the possible effects of future
changes to the definition.

Deprecate STATX_ALL in the uapi, while no damage has been done yet.

We could keep something like this around in the kernel, but there's
actually no point, since all filesystems should be explicitly checking
flags that they support and not rely on the VFS masking unknown ones out: a
flag could be known to the VFS, yet not known to the filesystem.

Cc: David Howells <dhowells@redhat.com>
Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
      581701b7
  11. 12 5月, 2020 1 次提交
  13. 10 5月, 2020 4 次提交
    • Y
      bpf: Add bpf_seq_printf and bpf_seq_write helpers · 492e639f
      由 Yonghong Song 提交于 
      Two helpers bpf_seq_printf and bpf_seq_write, are added for
writing data to the seq_file buffer.

bpf_seq_printf supports common format string flag/width/type
fields so at least I can get identical results for
netlink and ipv6_route targets.

For bpf_seq_printf and bpf_seq_write, return value -EOVERFLOW
specifically indicates a write failure due to overflow, which
means the object will be repeated in the next bpf invocation
if object collection stays the same. Note that if the object
collection is changed, depending how collection traversal is
done, even if the object still in the collection, it may not
be visited.

For bpf_seq_printf, format %s, %p{i,I}{4,6} needs to
read kernel memory. Reading kernel memory may fail in
the following two cases:
  - invalid kernel address, or
  - valid kernel address but requiring a major fault
If reading kernel memory failed, the %s string will be
an empty string and %p{i,I}{4,6} will be all 0.
Not returning error to bpf program is consistent with
what bpf_trace_printk() does for now.

bpf_seq_printf may return -EBUSY meaning that internal percpu
buffer for memory copy of strings or other pointees is
not available. Bpf program can return 1 to indicate it
wants the same object to be repeated. Right now, this should not
happen on no-RT kernels since migrate_disable(), which guards
bpf prog call, calls preempt_disable().
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175914.2476661-1-yhs@fb.com
      492e639f
    • Y
      bpf: Create anonymous bpf iterator · ac51d99b
      由 Yonghong Song 提交于 
      A new bpf command BPF_ITER_CREATE is added.

The anonymous bpf iterator is seq_file based.
The seq_file private data are referenced by targets.
The bpf_iter infrastructure allocated additional space
at seq_file->private before the space used by targets
to store some meta data, e.g.,
  prog:       prog to run
  session_id: an unique id for each opened seq_file
  seq_num:    how many times bpf programs are queried in this session
  done_stop:  an internal state to decide whether bpf program
              should be called in seq_ops->stop() or not

The seq_num will start from 0 for valid objects.
The bpf program may see the same seq_num more than once if
 - seq_file buffer overflow happens and the same object
   is retried by bpf_seq_read(), or
 - the bpf program explicitly requests a retry of the
   same object

Since module is not supported for bpf_iter, all target
registeration happens at __init time, so there is no
need to change bpf_iter_unreg_target() as it is used
mostly in error path of the init function at which time
no bpf iterators have been created yet.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175905.2475770-1-yhs@fb.com
      ac51d99b
    • Y
      bpf: Support bpf tracing/iter programs for BPF_LINK_CREATE · de4e05ca
      由 Yonghong Song 提交于 
      Given a bpf program, the step to create an anonymous bpf iterator is:
  - create a bpf_iter_link, which combines bpf program and the target.
    In the future, there could be more information recorded in the link.
    A link_fd will be returned to the user space.
  - create an anonymous bpf iterator with the given link_fd.

The bpf_iter_link can be pinned to bpffs mount file system to
create a file based bpf iterator as well.

The benefit to use of bpf_iter_link:
  - using bpf link simplifies design and implementation as bpf link
    is used for other tracing bpf programs.
  - for file based bpf iterator, bpf_iter_link provides a standard
    way to replace underlying bpf programs.
  - for both anonymous and free based iterators, bpf link query
    capability can be leveraged.

The patch added support of tracing/iter programs for BPF_LINK_CREATE.
A new link type BPF_LINK_TYPE_ITER is added to facilitate link
querying. Currently, only prog_id is needed, so there is no
additional in-kernel show_fdinfo() and fill_link_info() hook
is needed for BPF_LINK_TYPE_ITER link.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175901.2475084-1-yhs@fb.com
      de4e05ca
    • Y
      bpf: Allow loading of a bpf_iter program · 15d83c4d
      由 Yonghong Song 提交于 
      A bpf_iter program is a tracing program with attach type
BPF_TRACE_ITER. The load attribute
  attach_btf_id
is used by the verifier against a particular kernel function,
which represents a target, e.g., __bpf_iter__bpf_map
for target bpf_map which is implemented later.

The program return value must be 0 or 1 for now.
  0 : successful, except potential seq_file buffer overflow
      which is handled by seq_file reader.
  1 : request to restart the same object

In the future, other return values may be used for filtering or
teminating the iterator.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175900.2474947-1-yhs@fb.com
      15d83c4d
  15. 09 5月, 2020 1 次提交
    • S
      bpf: Allow any port in bpf_bind helper · 8086fbaf
      由 Stanislav Fomichev 提交于 
      We want to have a tighter control on what ports we bind to in
the BPF_CGROUP_INET{4,6}_CONNECT hooks even if it means
connect() becomes slightly more expensive. The expensive part
comes from the fact that we now need to call inet_csk_get_port()
that verifies that the port is not used and allocates an entry
in the hash table for it.

Since we can't rely on "snum || !bind_address_no_port" to prevent
us from calling POST_BIND hook anymore, let's add another bind flag
to indicate that the call site is BPF program.

v5:
* fix wrong AF_INET (should be AF_INET6) in the bpf program for v6

v3:
* More bpf_bind documentation refinements (Martin KaFai Lau)
* Add UDP tests as well (Martin KaFai Lau)
* Don't start the thread, just do socket+bind+listen (Martin KaFai Lau)

v2:
* Update documentation (Andrey Ignatov)
* Pass BIND_FORCE_ADDRESS_NO_PORT conditionally (Andrey Ignatov)
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAndrey Ignatov <rdna@fb.com>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200508174611.228805-5-sdf@google.com
      8086fbaf
  17. 02 5月, 2020 2 次提交
    • S
      bpf: Bpf_{g,s}etsockopt for struct bpf_sock_addr · beecf11b
      由 Stanislav Fomichev 提交于 
      Currently, bpf_getsockopt and bpf_setsockopt helpers operate on the
'struct bpf_sock_ops' context in BPF_PROG_TYPE_SOCK_OPS program.
Let's generalize them and make them available for 'struct bpf_sock_addr'.
That way, in the future, we can allow those helpers in more places.

As an example, let's expose those 'struct bpf_sock_addr' based helpers to
BPF_CGROUP_INET{4,6}_CONNECT hooks. That way we can override CC before the
connection is made.

v3:
* Expose custom helpers for bpf_sock_addr context instead of doing
  generic bpf_sock argument (as suggested by Daniel). Even with
  try_socket_lock that doesn't sleep we have a problem where context sk
  is already locked and socket lock is non-nestable.

v2:
* s/BPF_PROG_TYPE_CGROUP_SOCKOPT/BPF_PROG_TYPE_SOCK_OPS/
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200430233152.199403-1-sdf@google.com
      beecf11b
    • S
      bpf: Sharing bpf runtime stats with BPF_ENABLE_STATS · d46edd67
      由 Song Liu 提交于 
      Currently, sysctl kernel.bpf_stats_enabled controls BPF runtime stats.
Typical userspace tools use kernel.bpf_stats_enabled as follows:

  1. Enable kernel.bpf_stats_enabled;
  2. Check program run_time_ns;
  3. Sleep for the monitoring period;
  4. Check program run_time_ns again, calculate the difference;
  5. Disable kernel.bpf_stats_enabled.

The problem with this approach is that only one userspace tool can toggle
this sysctl. If multiple tools toggle the sysctl at the same time, the
measurement may be inaccurate.

To fix this problem while keep backward compatibility, introduce a new
bpf command BPF_ENABLE_STATS. On success, this command enables stats and
returns a valid fd. BPF_ENABLE_STATS takes argument "type". Currently,
only one type, BPF_STATS_RUN_TIME, is supported. We can extend the
command to support other types of stats in the future.

With BPF_ENABLE_STATS, user space tool would have the following flow:

  1. Get a fd with BPF_ENABLE_STATS, and make sure it is valid;
  2. Check program run_time_ns;
  3. Sleep for the monitoring period;
  4. Check program run_time_ns again, calculate the difference;
  5. Close the fd.
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200430071506.1408910-2-songliubraving@fb.com
      d46edd67
  19. 29 4月, 2020 1 次提交
  21. 28 4月, 2020 1 次提交
  23. 27 4月, 2020 1 次提交
  25. 25 4月, 2020 1 次提交
  27. 22 4月, 2020 1 次提交
  29. 21 4月, 2020 1 次提交
  31. 14 4月, 2020 10 次提交
    • A
      tools headers: Synchronize linux/bits.h with the kernel sources · e3698b23
      由 Arnaldo Carvalho de Melo 提交于 
      To pick up the changes in these csets:

  295bcca8 ("linux/bits.h: add compile time sanity check of GENMASK inputs")
  3945ff37 ("linux/bits.h: Extract common header for vDSO")

To address this tools/perf build warning:

  Warning: Kernel ABI header at 'tools/include/linux/bits.h' differs from latest version at 'include/linux/bits.h'
  diff -u tools/include/linux/bits.h include/linux/bits.h

This clashes with usage of userspace's static_assert(), that, at least
on glibc, is guarded by a ifnded/endif pair, do the same to our copy of
build_bug.h and avoid that diff in check_headers.sh so that we continue
checking for drifts with the kernel sources master copy.

This will all be tested with the set of build containers that includes
uCLibc, musl libc, lots of glibc versions in lots of distros and cross
build environments.

The tools/objtool, tools/bpf, etc were tested as well.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      e3698b23
    • A
      tools headers: Adopt verbatim copy of compiletime_assert() from kernel sources · 5b992add
      由 Arnaldo Carvalho de Melo 提交于 
      Will be needed when syncing the linux/bits.h header, in the next cset.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      5b992add
    • A
      tools headers UAPI: Sync drm/i915_drm.h with the kernel sources · 54a58ebc
      由 Arnaldo Carvalho de Melo 提交于 
      To pick the change in:

  88be76cd ("drm/i915: Allow userspace to specify ringsize on construction")

That don't result in any changes in tooling, just silences this perf
build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/drm/i915_drm.h' differs from latest version at 'include/uapi/drm/i915_drm.h'
  diff -u tools/include/uapi/drm/i915_drm.h include/uapi/drm/i915_drm.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      54a58ebc
    • A
      tools headers UAPI: Update tools's copy of drm.h headers · 0719bdf4
      由 Arnaldo Carvalho de Melo 提交于 
      Picking the changes from:

  455e00f1 ("drm: Add getfb2 ioctl")

Silencing these perf build warnings:

  Warning: Kernel ABI header at 'tools/include/uapi/drm/drm.h' differs from latest version at 'include/uapi/drm/drm.h'
  diff -u tools/include/uapi/drm/drm.h include/uapi/drm/drm.h

Now 'perf trace' and other code that might use the
tools/perf/trace/beauty autogenerated tables will be able to translate
this new ioctl code into a string:

  $ tools/perf/trace/beauty/drm_ioctl.sh > before
  $ cp include/uapi/drm/drm.h tools/include/uapi/drm/drm.h
  $ tools/perf/trace/beauty/drm_ioctl.sh > after
  $ diff -u before after
  --- before	2020-04-14 09:28:45.461821077 -0300
  +++ after	2020-04-14 09:28:53.594782685 -0300
  @@ -107,6 +107,7 @@
   	[0xCB] = "SYNCOBJ_QUERY",
   	[0xCC] = "SYNCOBJ_TRANSFER",
   	[0xCD] = "SYNCOBJ_TIMELINE_SIGNAL",
  +	[0xCE] = "MODE_GETFB2",
   	[DRM_COMMAND_BASE + 0x00] = "I915_INIT",
   	[DRM_COMMAND_BASE + 0x01] = "I915_FLUSH",
   	[DRM_COMMAND_BASE + 0x02] = "I915_FLIP",
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Daniel Stone <daniels@collabora.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      0719bdf4
    • A
      tools headers kvm: Sync linux/kvm.h with the kernel sources · b8fc2280
      由 Arnaldo Carvalho de Melo 提交于 
      To pick up the changes from:

  9a5788c6 ("KVM: PPC: Book3S HV: Add a capability for enabling secure guests")
  3c9bd400 ("KVM: x86: enable dirty log gradually in small chunks")
  13da9ae1 ("KVM: s390: protvirt: introduce and enable KVM_CAP_S390_PROTECTED")
  e0d2773d ("KVM: s390: protvirt: UV calls in support of diag308 0, 1")
  19e12277 ("KVM: S390: protvirt: Introduce instruction data area bounce buffer")
  29b40f10 ("KVM: s390: protvirt: Add initial vm and cpu lifecycle handling")

So far we're ignoring those arch specific ioctls, we need to revisit
this at some time to have arch specific tables, etc:

  $ grep S390 tools/perf/trace/beauty/kvm_ioctl.sh
      egrep -v " ((ARM|PPC|S390)_|[GS]ET_(DEBUGREGS|PIT2|XSAVE|TSC_KHZ)|CREATE_SPAPR_TCE_64)" | \
  $

This addresses these tools/perf build warnings:

  Warning: Kernel ABI header at 'tools/arch/arm/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm/include/uapi/asm/kvm.h'
  diff -u tools/arch/arm/include/uapi/asm/kvm.h arch/arm/include/uapi/asm/kvm.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jay Zhou <jianjay.zhou@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      b8fc2280
    • A
      tools headers UAPI: Sync linux/fscrypt.h with the kernel sources · 1abcb9d9
      由 Arnaldo Carvalho de Melo 提交于 
      To pick the changes from:

  e98ad464 ("fscrypt: add FS_IOC_GET_ENCRYPTION_NONCE ioctl")

That don't trigger any changes in tooling.

This silences this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/fscrypt.h' differs from latest version at 'include/uapi/linux/fscrypt.h'
  diff -u tools/include/uapi/linux/fscrypt.h include/uapi/linux/fscrypt.h

In time we should come up with something like:

  $ tools/perf/trace/beauty/fsconfig.sh
  static const char *fsconfig_cmds[] = {
  	[0] = "SET_FLAG",
  	[1] = "SET_STRING",
  	[2] = "SET_BINARY",
  	[3] = "SET_PATH",
  	[4] = "SET_PATH_EMPTY",
  	[5] = "SET_FD",
  	[6] = "CMD_CREATE",
  	[7] = "CMD_RECONFIGURE",
  };
  $

And:

  $ tools/perf/trace/beauty/drm_ioctl.sh | head
  #ifndef DRM_COMMAND_BASE
  #define DRM_COMMAND_BASE                0x40
  #endif
  static const char *drm_ioctl_cmds[] = {
  	[0x00] = "VERSION",
  	[0x01] = "GET_UNIQUE",
  	[0x02] = "GET_MAGIC",
  	[0x03] = "IRQ_BUSID",
  	[0x04] = "GET_MAP",
  	[0x05] = "GET_CLIENT",
  $

For fscrypt's ioctls.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      1abcb9d9
    • A
      tools include UAPI: Sync linux/vhost.h with the kernel sources · 3df4d4bf
      由 Arnaldo Carvalho de Melo 提交于 
      To get the changes in:

  4c8cf318 ("vhost: introduce vDPA-based backend")

Silencing this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/vhost.h' differs from latest version at 'include/uapi/linux/vhost.h'
  diff -u tools/include/uapi/linux/vhost.h include/uapi/linux/vhost.h

This automatically picks these new ioctls, making tools such as 'perf
trace' aware of them and possibly allowing to use the strings in
filters, etc:

  $ tools/perf/trace/beauty/vhost_virtio_ioctl.sh > before
  $ cp include/uapi/linux/vhost.h tools/include/uapi/linux/vhost.h
  $ tools/perf/trace/beauty/vhost_virtio_ioctl.sh > after
  $ diff -u before after
  --- before	2020-04-14 09:12:28.559748968 -0300
  +++ after	2020-04-14 09:12:38.781696242 -0300
  @@ -24,9 +24,16 @@
   	[0x44] = "SCSI_GET_EVENTS_MISSED",
   	[0x60] = "VSOCK_SET_GUEST_CID",
   	[0x61] = "VSOCK_SET_RUNNING",
  +	[0x72] = "VDPA_SET_STATUS",
  +	[0x74] = "VDPA_SET_CONFIG",
  +	[0x75] = "VDPA_SET_VRING_ENABLE",
   };
   static const char *vhost_virtio_ioctl_read_cmds[] = {
   	[0x00] = "GET_FEATURES",
   	[0x12] = "GET_VRING_BASE",
   	[0x26] = "GET_BACKEND_FEATURES",
  +	[0x70] = "VDPA_GET_DEVICE_ID",
  +	[0x71] = "VDPA_GET_STATUS",
  +	[0x73] = "VDPA_GET_CONFIG",
  +	[0x76] = "VDPA_GET_VRING_NUM",
   };
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tiwei Bie <tiwei.bie@intel.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      3df4d4bf
    • A
      tools headers UAPI: Sync linux/mman.h with the kernel · f60b3878
      由 Arnaldo Carvalho de Melo 提交于 
      To get the changes in:

  e346b381 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()")

Add that to 'perf trace's mremap 'flags' decoder.

This silences this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/mman.h' differs from latest version at 'include/uapi/linux/mman.h'
  diff -u tools/include/uapi/linux/mman.h include/uapi/linux/mman.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Brian Geffon <bgeffon@google.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      f60b3878
    • A
      tools headers UAPI: Sync sched.h with the kernel · 027fa8fb
      由 Arnaldo Carvalho de Melo 提交于 
      To get the changes in:

  ef2c41cf ("clone3: allow spawning processes into cgroups")

Add that to 'perf trace's clone 'flags' decoder.

This silences this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/sched.h' differs from latest version at 'include/uapi/linux/sched.h'
  diff -u tools/include/uapi/linux/sched.h include/uapi/linux/sched.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      027fa8fb
    • A
      tools headers: Update linux/vdso.h and grab a copy of vdso/const.h · ca64d84e
      由 Arnaldo Carvalho de Melo 提交于 
      To get in line with:

  8165b57b ("linux/const.h: Extract common header for vDSO")

And silence this tools/perf/ build warning:

  Warning: Kernel ABI header at 'tools/include/linux/const.h' differs from latest version at 'include/linux/const.h'
  diff -u tools/include/linux/const.h include/linux/const.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      ca64d84e
  33. 02 4月, 2020 1 次提交
  35. 31 3月, 2020 2 次提交
    • A
      libbpf: Add support for bpf_link-based cgroup attachment · cc4f864b
      由 Andrii Nakryiko 提交于 
      Add bpf_program__attach_cgroup(), which uses BPF_LINK_CREATE subcommand to
create an FD-based kernel bpf_link. Also add low-level bpf_link_create() API.

If expected_attach_type is not specified explicitly with
bpf_program__set_expected_attach_type(), libbpf will try to determine proper
attach type from BPF program's section definition.

Also add support for bpf_link's underlying BPF program replacement:
  - unconditional through high-level bpf_link__update_program() API;
  - cmpxchg-like with specifying expected current BPF program through
    low-level bpf_link_update() API.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200330030001.2312810-4-andriin@fb.com
      cc4f864b
    • A
      bpf: Implement bpf_link-based cgroup BPF program attachment · af6eea57
      由 Andrii Nakryiko 提交于 
      Implement new sub-command to attach cgroup BPF programs and return FD-based
bpf_link back on success. bpf_link, once attached to cgroup, cannot be
replaced, except by owner having its FD. Cgroup bpf_link supports only
BPF_F_ALLOW_MULTI semantics. Both link-based and prog-based BPF_F_ALLOW_MULTI
attachments can be freely intermixed.

To prevent bpf_cgroup_link from keeping cgroup alive past the point when no
BPF program can be executed, implement auto-detachment of link. When
cgroup_bpf_release() is called, all attached bpf_links are forced to release
cgroup refcounts, but they leave bpf_link otherwise active and allocated, as
well as still owning underlying bpf_prog. This is because user-space might
still have FDs open and active, so bpf_link as a user-referenced object can't
be freed yet. Once last active FD is closed, bpf_link will be freed and
underlying bpf_prog refcount will be dropped. But cgroup refcount won't be
touched, because cgroup is released already.

The inherent race between bpf_cgroup_link release (from closing last FD) and
cgroup_bpf_release() is resolved by both operations taking cgroup_mutex. So
the only additional check required is when bpf_cgroup_link attempts to detach
itself from cgroup. At that time we need to check whether there is still
cgroup associated with that link. And if not, exit with success, because
bpf_cgroup_link was already successfully detached.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NRoman Gushchin <guro@fb.com>
Link: https://lore.kernel.org/bpf/20200330030001.2312810-2-andriin@fb.com
      af6eea57