Martin KaFai Lau says:
====================
From: Martin KaFai Lau <martin.lau@kernel.org>
The earlier commits [0] removed duplicated code from bpf_setsockopt().
This series is to remove duplicated code from bpf_getsockopt().
Unlike the setsockopt() which had already changed to take
the sockptr_t argument, the same has not been done to
getsockopt(). This is the extra step being done in this
series.
[0]: https://lore.kernel.org/all/20220817061704.4174272-1-kafai@fb.com/
v2:
- The previous v2 did not reach the list. It is a resend.
- Add comments on bpf_getsockopt() should not free
the saved_syn (Stanislav)
- Explicitly null-terminate the tcp-cc name (Stanislav)
====================
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch removes the __bpf_getsockopt() which directly
reads the sk by using PTR_TO_BTF_ID. Instead, the test now directly
uses the kernel bpf helper bpf_getsockopt() which supports all
the required optname now.
TCP_SAVE[D]_SYN and TCP_MAXSEG are not tested in a loop for all
the hooks and sock_ops's cb. TCP_SAVE[D]_SYN only works
in passive connection. TCP_MAXSEG only works when
it is setsockopt before the connection is established and
the getsockopt return value can only be tested after
the connection is established.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002937.2896904-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch changes bpf_getsockopt(SOL_IPV6) to reuse
do_ipv6_getsockopt(). It removes the duplicated code from
bpf_getsockopt(SOL_IPV6).
This also makes bpf_getsockopt(SOL_IPV6) supporting the same
set of optnames as in bpf_setsockopt(SOL_IPV6). In particular,
this adds IPV6_AUTOFLOWLABEL support to bpf_getsockopt(SOL_IPV6).
ipv6 could be compiled as a module. Like how other code solved it
with stubs in ipv6_stubs.h, this patch adds the do_ipv6_getsockopt
to the ipv6_bpf_stub.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002931.2896218-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch changes bpf_getsockopt(SOL_IP) to reuse
do_ip_getsockopt() and remove the duplicated code.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002925.2895416-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch changes bpf_getsockopt(SOL_TCP) to reuse
do_tcp_getsockopt(). It removes the duplicated code from
bpf_getsockopt(SOL_TCP).
Before this patch, there were some optnames available to
bpf_setsockopt(SOL_TCP) but missing in bpf_getsockopt(SOL_TCP).
For example, TCP_NODELAY, TCP_MAXSEG, TCP_KEEPIDLE, TCP_KEEPINTVL,
and a few more. It surprises users from time to time. This patch
automatically closes this gap without duplicating more code.
bpf_getsockopt(TCP_SAVED_SYN) does not free the saved_syn,
so it stays in sol_tcp_sockopt().
For string name value like TCP_CONGESTION, bpf expects it
is always null terminated, so sol_tcp_sockopt() decrements
optlen by one before calling do_tcp_getsockopt() and
the 'if (optlen < saved_optlen) memset(..,0,..);'
in __bpf_getsockopt() will always do a null termination.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002918.2894511-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch changes bpf_getsockopt(SOL_SOCKET) to reuse
sk_getsockopt(). It removes all duplicated code from
bpf_getsockopt(SOL_SOCKET).
Before this patch, there were some optnames available to
bpf_setsockopt(SOL_SOCKET) but missing in bpf_getsockopt(SOL_SOCKET).
It surprises users from time to time. For example, SO_REUSEADDR,
SO_KEEPALIVE, SO_RCVLOWAT, and SO_MAX_PACING_RATE. This patch
automatically closes this gap without duplicating more code.
The only exception is SO_BINDTODEVICE because it needs to acquire a
blocking lock. Thus, SO_BINDTODEVICE is not supported.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002912.2894040-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch moves the "#ifdef CONFIG_XXX" check into the "if/else"
statement itself. The change is done for the bpf_getsockopt()
function only. It will make the latter patches easier to follow
without the surrounding ifdef macro.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002906.2893572-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Similar to the earlier patch that changes sk_getsockopt() to
use sockopt_{lock,release}_sock() such that it can avoid taking the
lock when called from bpf. This patch also changes do_ipv6_getsockopt()
to use sockopt_{lock,release}_sock() such that bpf_getsockopt(SOL_IPV6)
can reuse do_ipv6_getsockopt().
Although bpf_getsockopt(SOL_IPV6) currently does not support optname
that requires lock_sock(), using sockopt_{lock,release}_sock()
consistently across *_getsockopt() will make future optname addition
harder to miss the sockopt_{lock,release}_sock() usage. eg. when
adding new optname that requires a lock and the new optname is
needed in bpf_getsockopt() also.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002859.2893064-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Similar to the earlier patch that changes sk_getsockopt() to
take the sockptr_t argument . This patch also changes
do_ipv6_getsockopt() to take the sockptr_t argument such that
a latter patch can make bpf_getsockopt(SOL_IPV6) to reuse
do_ipv6_getsockopt().
Note on the change in ip6_mc_msfget(). This function is to
return an array of sockaddr_storage in optval. This function
is shared between ipv6_get_msfilter() and compat_ipv6_get_msfilter().
However, the sockaddr_storage is stored at different offset of the
optval because of the difference between group_filter and
compat_group_filter. Thus, a new 'ss_offset' argument is
added to ip6_mc_msfget().
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002853.2892532-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pass the len to the compat_ipv6_get_msfilter() instead of
compat_ipv6_get_msfilter() getting it again from optlen.
Its counter part ipv6_get_msfilter() is also taking the
len from do_ipv6_getsockopt().
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002846.2892091-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Similar to the earlier commit that changed sk_setsockopt() to
use sockopt_{lock,release}_sock() such that it can avoid taking
lock when called from bpf. This patch also changes do_ip_getsockopt()
to use sockopt_{lock,release}_sock() such that a latter patch can
make bpf_getsockopt(SOL_IP) to reuse do_ip_getsockopt().
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002834.2891514-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Similar to the earlier patch that changes sk_getsockopt() to
take the sockptr_t argument. This patch also changes
do_ip_getsockopt() to take the sockptr_t argument such that
a latter patch can make bpf_getsockopt(SOL_IP) to reuse
do_ip_getsockopt().
Note on the change in ip_mc_gsfget(). This function is to
return an array of sockaddr_storage in optval. This function
is shared between ip_get_mcast_msfilter() and
compat_ip_get_mcast_msfilter(). However, the sockaddr_storage
is stored at different offset of the optval because of
the difference between group_filter and compat_group_filter.
Thus, a new 'ss_offset' argument is added to ip_mc_gsfget().
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002828.2890585-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Similar to the earlier commit that changed sk_setsockopt() to
use sockopt_{lock,release}_sock() such that it can avoid taking
lock when called from bpf. This patch also changes do_tcp_getsockopt()
to use sockopt_{lock,release}_sock() such that a latter patch can
make bpf_getsockopt(SOL_TCP) to reuse do_tcp_getsockopt().
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002821.2889765-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Similar to the earlier patch that changes sk_getsockopt() to
take the sockptr_t argument . This patch also changes
do_tcp_getsockopt() to take the sockptr_t argument such that
a latter patch can make bpf_getsockopt(SOL_TCP) to reuse
do_tcp_getsockopt().
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002815.2889332-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Similar to the earlier commit that changed sk_setsockopt() to
use sockopt_{lock,release}_sock() such that it can avoid taking
lock when called from bpf. This patch also changes sk_getsockopt()
to use sockopt_{lock,release}_sock() such that a latter patch can
make bpf_getsockopt(SOL_SOCKET) to reuse sk_getsockopt().
Only sk_get_filter() requires this change and it is used by
the optname SO_GET_FILTER.
The '.getname' implementations in sock->ops->getname() is not
changed also since bpf does not always have the sk->sk_socket
pointer and cannot support SO_PEERNAME.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002809.2888981-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch changes sk_getsockopt() to take the sockptr_t argument
such that it can be used by bpf_getsockopt(SOL_SOCKET) in a
latter patch.
security_socket_getpeersec_stream() is not changed. It stays
with the __user ptr (optval.user and optlen.user) to avoid changes
to other security hooks. bpf_getsockopt(SOL_SOCKET) also does not
support SO_PEERSEC.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002802.2888419-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A latter patch refactors bpf_getsockopt(SOL_SOCKET) with the
sock_getsockopt() to avoid code duplication and code
drift between the two duplicates.
The current sock_getsockopt() takes sock ptr as the argument.
The very first thing of this function is to get back the sk ptr
by 'sk = sock->sk'.
bpf_getsockopt() could be called when the sk does not have
the sock ptr created. Meaning sk->sk_socket is NULL. For example,
when a passive tcp connection has just been established but has yet
been accept()-ed. Thus, it cannot use the sock_getsockopt(sk->sk_socket)
or else it will pass a NULL ptr.
This patch moves all sock_getsockopt implementation to the newly
added sk_getsockopt(). The new sk_getsockopt() takes a sk ptr
and immediately gets the sock ptr by 'sock = sk->sk_socket'
The existing sock_getsockopt(sock) is changed to call
sk_getsockopt(sock->sk). All existing callers have both sock->sk
and sk->sk_socket pointer.
The latter patch will make bpf_getsockopt(SOL_SOCKET) call
sk_getsockopt(sk) directly. The bpf_getsockopt(SOL_SOCKET) does
not use the optnames that require sk->sk_socket, so it will
be safe.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002756.2887884-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The put lowers the reference count to 0 and frees ctx, reading it
afterwards is invalid. Move the put after the uses and determine the
last use by the reference count being 1.
Fixes: 39e940d4ab ("selftests/xsk: Destroy BPF resources only when ctx refcount drops to 0")
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20220901202645.1463552-1-irogers@google.com
BPF object files are, in a way, the final artifact produced as part of
the ahead-of-time compilation process. That makes them somewhat special
compared to "regular" object files, which are a intermediate build
artifacts that can typically be removed safely. As such, it can make
sense to name them differently to make it easier to spot this difference
at a glance.
Among others, libbpf-bootstrap [0] has established the extension .bpf.o
for BPF object files. It seems reasonable to follow this example and
establish the same denomination for selftest build artifacts. To that
end, this change adjusts the corresponding part of the build system and
the test programs loading BPF object files to work with .bpf.o files.
[0] https://github.com/libbpf/libbpf-bootstrap
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220901222253.1199242-1-deso@posteo.net
Introduce new mode to xdpxceiver responsible for testing AF_XDP zero
copy support of driver that serves underlying physical device. When
setting up test suite, determine whether driver has ZC support or not by
trying to bind XSK ZC socket to the interface. If it succeeded,
interpret it as ZC support being in place and do softirq and busy poll
tests for zero copy mode.
Note that Rx dropped tests are skipped since ZC path is not touching
rx_dropped stat at all.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20220901114813.16275-7-maciej.fijalkowski@intel.com
For single threaded poll tests call pthread_kill() from main thread so
that we are sure worker thread has finished its job and it is possible
to proceed with next test types from test suite. It was observed that on
some platforms it takes a bit longer for worker thread to exit and next
test case sees device as busy in this case.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20220901114813.16275-6-maciej.fijalkowski@intel.com
Currently, architecture of xdpxceiver is designed strictly for
conducting veth based tests. Veth pair is created together with a
network namespace and one of the veth interfaces is moved to the
mentioned netns. Then, separate threads for Tx and Rx are spawned which
will utilize described setup.
Infrastructure described in the paragraph above can not be used for
testing AF_XDP support on physical devices. That testing will be
conducted on a single network interface and same queue. Xskxceiver
needs to be extended to distinguish between veth tests and physical
interface tests.
Since same iface/queue id pair will be used by both Tx/Rx threads for
physical device testing, Tx thread, which happen to run after the Rx
thread, is going to create XSK socket with shared umem flag. In order to
track this setting throughout the lifetime of spawned threads, introduce
'shared_umem' boolean variable to struct ifobject and set it to true
when xdpxceiver is run against physical device. In such case, UMEM size
needs to be doubled, so half of it will be used by Rx thread and other
half by Tx thread. For two step based test types, value of XSKMAP
element under key 0 has to be updated as there is now another socket for
the second step. Also, to avoid race conditions when destroying XSK
resources, move this activity to the main thread after spawned Rx and Tx
threads have finished its job. This way it is possible to gracefully
remove shared umem without introducing synchronization mechanisms.
To run xsk selftests suite on physical device, append "-i $IFACE" when
invoking test_xsk.sh. For veth based tests, simply skip it. When "-i
$IFACE" is in place, under the hood test_xsk.sh will use $IFACE for both
interfaces supplied to xdpxceiver, which in turn will interpret that
this execution of test suite is for a physical device.
Note that currently this makes it possible only to test SKB and DRV mode
(in case underlying device has native XDP support). ZC testing support
is added in a later patch.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20220901114813.16275-5-maciej.fijalkowski@intel.com
So that "enp240s0f0" or such name can be used against xskxceiver.
While at it, also extend character count for netns name.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20220901114813.16275-4-maciej.fijalkowski@intel.com
In order to prepare xdpxceiver for physical device testing, let us
introduce default Rx pkt stream. Reason for doing it is that physical
device testing will use a UMEM with a doubled size where half of it will
be used by Tx and other half by Rx. This means that pkt addresses will
differ for Tx and Rx streams. Rx thread will initialize the
xsk_umem_info::base_addr that is added here so that pkt_set(), when
working on Rx UMEM will add this offset and second half of UMEM space
will be used. Note that currently base_addr is 0 on both sides. Future
commit will do the mentioned initialization.
Previously, veth based testing worked on separate UMEMs, so single
default stream was fine.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20220901114813.16275-3-maciej.fijalkowski@intel.com
Currently, xdpxceiver assumes that underlying device supports XDP in
native mode - it is fine by now since tests can run only on a veth pair.
Future commit is going to allow running test suite against physical
devices, so let us query the device if it is capable of running XDP
programs in native mode. This way xdpxceiver will not try to run
TEST_MODE_DRV if device being tested is not supporting it.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20220901114813.16275-2-maciej.fijalkowski@intel.com
Get the tunnel flags in {ipv6}vxlan_get_tunnel_src and ensure they are
aligned with tunnel params set at {ipv6}vxlan_set_tunnel_dst.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220831144010.174110-2-shmulik.ladkani@gmail.com
Existing 'bpf_skb_get_tunnel_key' extracts various tunnel parameters
(id, ttl, tos, local and remote) but does not expose ip_tunnel_info's
tun_flags to the BPF program.
It makes sense to expose tun_flags to the BPF program.
Assume for example multiple GRE tunnels maintained on a single GRE
interface in collect_md mode. The program expects origins to initiate
over GRE, however different origins use different GRE characteristics
(e.g. some prefer to use GRE checksum, some do not; some pass a GRE key,
some do not, etc..).
A BPF program getting tun_flags can therefore remember the relevant
flags (e.g. TUNNEL_CSUM, TUNNEL_SEQ...) for each initiating remote. In
the reply path, the program can use 'bpf_skb_set_tunnel_key' in order
to correctly reply to the remote, using similar characteristics, based
on the stored tunnel flags.
Introduce BPF_F_TUNINFO_FLAGS flag for bpf_skb_get_tunnel_key. If
specified, 'bpf_tunnel_key->tunnel_flags' is set with the tun_flags.
Decided to use the existing unused 'tunnel_ext' as the storage for the
'tunnel_flags' in order to avoid changing bpf_tunnel_key's layout.
Also, the following has been considered during the design:
1. Convert the "interesting" internal TUNNEL_xxx flags back to BPF_F_yyy
and place into the new 'tunnel_flags' field. This has 2 drawbacks:
- The BPF_F_yyy flags are from *set_tunnel_key* enumeration space,
e.g. BPF_F_ZERO_CSUM_TX. It is awkward that it is "returned" into
tunnel_flags from a *get_tunnel_key* call.
- Not all "interesting" TUNNEL_xxx flags can be mapped to existing
BPF_F_yyy flags, and it doesn't make sense to create new BPF_F_yyy
flags just for purposes of the returned tunnel_flags.
2. Place key.tun_flags into 'tunnel_flags' but mask them, keeping only
"interesting" flags. That's ok, but the drawback is that what's
"interesting" for my usecase might be limiting for other usecases.
Therefore I decided to expose what's in key.tun_flags *as is*, which seems
most flexible. The BPF user can just choose to ignore bits he's not
interested in. The TUNNEL_xxx are also UAPI, so no harm exposing them
back in the get_tunnel_key call.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220831144010.174110-1-shmulik.ladkani@gmail.com
When CONFIG_SECURITY_NETWORK is disabled, there will be build warnings
from resolve_btfids:
WARN: resolve_btfids: unresolved symbol bpf_lsm_socket_socketpair
......
WARN: resolve_btfids: unresolved symbol bpf_lsm_inet_conn_established
Fixing it by wrapping these BTF ID definitions by CONFIG_SECURITY_NETWORK.
Fixes: 69fd337a97 ("bpf: per-cgroup lsm flavor")
Fixes: 9113d7e48e ("bpf: expose bpf_{g,s}etsockopt to lsm cgroup")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220901065126.3856297-1-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The assignment of the else and else if branches is the same, so the else
if here is redundant, so we remove it and add a comment to make the code
here readable.
./kernel/bpf/cgroup_iter.c:81:6-8: WARNING: possible condition with no effect (if == else).
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2016
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220831021618.86770-1-jiapeng.chong@linux.alibaba.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Hou Tao says:
====================
From: Hou Tao <houtao1@huawei.com>
Hi,
The patchset aims to make the update of per-cpu prog->active and per-cpu
bpf_task_storage_busy being preemption-safe. The problem is on same
architectures (e.g. arm64), __this_cpu_{inc|dec|inc_return} are neither
preemption-safe nor IRQ-safe, so under fully preemptible kernel the
concurrent updates on these per-cpu variables may be interleaved and the
final values of these variables may be not zero.
Patch 1 & 2 use the preemption-safe per-cpu helpers to manipulate
prog->active and bpf_task_storage_busy. Patch 3 & 4 add a test case in
map_tests to show the concurrent updates on the per-cpu
bpf_task_storage_busy by using __this_cpu_{inc|dec} are not atomic.
Comments are always welcome.
Regards,
Tao
Change Log:
v2:
* Patch 1: update commit message to indicate the problem is only
possible for fully preemptible kernel
* Patch 2: a new patch which fixes the problem for prog->active
* Patch 3 & 4: move it to test_maps and make it depend on CONFIG_PREEMPT
v1: https://lore.kernel.org/bpf/20220829142752.330094-1-houtao@huaweicloud.com/
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Under full preemptible kernel, task local storage lookup operations on
the same CPU may update per-cpu bpf_task_storage_busy concurrently. If
the update of bpf_task_storage_busy is not preemption safe, the final
value of bpf_task_storage_busy may become not-zero forever and
bpf_task_storage_trylock() will always fail. So add a test case to
ensure the update of bpf_task_storage_busy is preemption safe.
Will skip the test case when CONFIG_PREEMPT is disabled, and it can only
reproduce the problem probabilistically. By increasing
TASK_STORAGE_MAP_NR_LOOP and running it under ARM64 VM with 4-cpus, it
takes about four rounds to reproduce:
> test_maps is modified to only run test_task_storage_map_stress_lookup()
$ export TASK_STORAGE_MAP_NR_THREAD=256
$ export TASK_STORAGE_MAP_NR_LOOP=81920
$ export TASK_STORAGE_MAP_PIN_CPU=1
$ time ./test_maps
test_task_storage_map_stress_lookup(135):FAIL:bad bpf_task_storage_busy got -2
real 0m24.743s
user 0m6.772s
sys 0m17.966s
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20220901061938.3789460-5-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
sys_pidfd_open() is defined twice in both test_bprm_opts.c and
test_local_storage.c, so move it to a common header file. And it will be
used in map_tests as well.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20220901061938.3789460-4-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Both __this_cpu_inc_return() and __this_cpu_dec() are not preemption
safe and now migrate_disable() doesn't disable preemption, so the update
of prog-active is not atomic and in theory under fully preemptible kernel
recurisve prevention may do not work.
Fixing by using the preemption-safe and IRQ-safe variants.
Fixes: ca06f55b90 ("bpf: Add per-program recursion prevention mechanism")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20220901061938.3789460-3-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Now migrate_disable() does not disable preemption and under some
architectures (e.g. arm64) __this_cpu_{inc|dec|inc_return} are neither
preemption-safe nor IRQ-safe, so for fully preemptible kernel concurrent
lookups or updates on the same task local storage and on the same CPU
may make bpf_task_storage_busy be imbalanced, and
bpf_task_storage_trylock() on the specific cpu will always fail.
Fixing it by using this_cpu_{inc|dec|inc_return} when manipulating
bpf_task_storage_busy.
Fixes: bc235cdb42 ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20220901061938.3789460-2-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Hou Tao says:
====================
From: Hou Tao <houtao1@huawei.com>
Hi,
The patchset aims to fix the issues found during investigating the
syzkaller problem reported in [0]. It seems that the concurrent updates
to the same hash-table bucket may fail as shown in patch 1.
Patch 1 uses preempt_disable() to fix the problem for
htab_use_raw_lock() case. For !htab_use_raw_lock() case, the problem is
left to "BPF specific memory allocator" patchset [1] in which
!htab_use_raw_lock() will be removed.
Patch 2 fixes the out-of-bound memory read problem reported in [0]. The
problem has the root cause as patch 1 and it is fixed by handling -EBUSY
from htab_lock_bucket() correctly.
Patch 3 add two cases for hash-table update: one for the reentrancy of
bpf_map_update_elem(), and another one for concurrent updates of the
same hash-table bucket.
Comments are always welcome.
Regards,
Tao
[0]: https://lore.kernel.org/bpf/CACkBjsbuxaR6cv0kXJoVnBfL9ZJXjjoUcMpw_Ogc313jSrg14A@mail.gmail.com/
[1]: https://lore.kernel.org/bpf/20220819214232.18784-1-alexei.starovoitov@gmail.com/
Change Log:
v4:
* rebased on bpf-next
* add htab_update to DENYLIST.s390x
v3: https://lore.kernel.org/bpf/20220829023709.1958204-1-houtao@huaweicloud.com/
* patch 1: update commit message and add Fixes tag
* patch 2: add Fixes tag
* patch 3: elaborate the description of test cases
v2: https://lore.kernel.org/bpf/bd60ef93-1c6a-2db2-557d-b09b92ad22bd@huaweicloud.com/
* Note the fix is for CONFIG_PREEMPT case in commit message and add
Reviewed-by tag for patch 1
* Drop patch "bpf: Allow normally concurrent map updates for !htab_use_raw_lock() case"
v1: https://lore.kernel.org/bpf/20220821033223.2598791-1-houtao@huaweicloud.com/
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
One test demonstrates the reentrancy of hash map update on the same
bucket should fail, and another one shows concureently updates of
the same hash map bucket should succeed and not fail due to
the reentrancy checking for bucket lock.
There is no trampoline support on s390x, so move htab_update to
denylist.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220831042629.130006-4-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
In __htab_map_lookup_and_delete_batch() if htab_lock_bucket() returns
-EBUSY, it will go to next bucket. Going to next bucket may not only
skip the elements in current bucket silently, but also incur
out-of-bound memory access or expose kernel memory to userspace if
current bucket_cnt is greater than bucket_size or zero.
Fixing it by stopping batch operation and returning -EBUSY when
htab_lock_bucket() fails, and the application can retry or skip the busy
batch as needed.
Fixes: 20b6cc34ea ("bpf: Avoid hashtab deadlock with map_locked")
Reported-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220831042629.130006-3-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Per-cpu htab->map_locked is used to prohibit the concurrent accesses
from both NMI and non-NMI contexts. But since commit 74d862b682
("sched: Make migrate_disable/enable() independent of RT"),
migrate_disable() is also preemptible under CONFIG_PREEMPT case, so now
map_locked also disallows concurrent updates from normal contexts
(e.g. userspace processes) unexpectedly as shown below:
process A process B
htab_map_update_elem()
htab_lock_bucket()
migrate_disable()
/* return 1 */
__this_cpu_inc_return()
/* preempted by B */
htab_map_update_elem()
/* the same bucket as A */
htab_lock_bucket()
migrate_disable()
/* return 2, so lock fails */
__this_cpu_inc_return()
return -EBUSY
A fix that seems feasible is using in_nmi() in htab_lock_bucket() and
only checking the value of map_locked for nmi context. But it will
re-introduce dead-lock on bucket lock if htab_lock_bucket() is re-entered
through non-tracing program (e.g. fentry program).
One cannot use preempt_disable() to fix this issue as htab_use_raw_lock
being false causes the bucket lock to be a spin lock which can sleep and
does not work with preempt_disable().
Therefore, use migrate_disable() when using the spinlock instead of
preempt_disable() and defer fixing concurrent updates to when the kernel
has its own BPF memory allocator.
Fixes: 74d862b682 ("sched: Make migrate_disable/enable() independent of RT")
Reviewed-by: Hao Luo <haoluo@google.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220831042629.130006-2-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This patch adds a test to ensure bpf_setsockopt(TCP_CONGESTION, "not_exist")
will not trigger the kernel module autoload.
Before the fix:
[ 40.535829] BUG: sleeping function called from invalid context at include/linux/sched/mm.h:274
[...]
[ 40.552134] tcp_ca_find_autoload.constprop.0+0xcb/0x200
[ 40.552689] tcp_set_congestion_control+0x99/0x7b0
[ 40.553203] do_tcp_setsockopt+0x3ed/0x2240
[...]
[ 40.556041] __bpf_setsockopt+0x124/0x640
Signed-off-by: Martin KaFai Lau <martin.lau@linux.dev>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220830231953.792412-1-martin.lau@linux.dev
When bpf prog changes tcp-cc by calling bpf_setsockopt(TCP_CONGESTION),
it should not try to load module which may be a blocking operation.
This details was correct in the v1 [0] but missed by mistake in the
later revision in commit cb388e7ee3 ("bpf: net: Change do_tcp_setsockopt()
to use the sockopt's lock_sock() and capable()"). This patch fixes it by
checking the has_current_bpf_ctx().
[0] https://lore.kernel.org/bpf/20220727060921.2373314-1-kafai@fb.com/
Fixes: cb388e7ee3 ("bpf: net: Change do_tcp_setsockopt() to use the sockopt's lock_sock() and capable()")
Signed-off-by: Martin KaFai Lau <martin.lau@linux.dev>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220830231946.791504-1-martin.lau@linux.dev
The bpf_tail_call_static function is currently not defined unless
using clang >= 8.
To support bpf_tail_call_static on GCC we can check if __clang__ is
not defined to enable bpf_tail_call_static.
We need to use GCC assembly syntax when the compiler does not define
__clang__ as LLVM inline assembly is not fully compatible with GCC.
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220829210546.755377-1-james.hilliard1@gmail.com
Support dumping info of a cgroup_iter link. This includes
showing the cgroup's id and the order for walking the cgroup
hierarchy. Example output is as follows:
> bpftool link show
1: iter prog 2 target_name bpf_map
2: iter prog 3 target_name bpf_prog
3: iter prog 12 target_name cgroup cgroup_id 72 order self_only
> bpftool -p link show
[{
"id": 1,
"type": "iter",
"prog_id": 2,
"target_name": "bpf_map"
},{
"id": 2,
"type": "iter",
"prog_id": 3,
"target_name": "bpf_prog"
},{
"id": 3,
"type": "iter",
"prog_id": 12,
"target_name": "cgroup",
"cgroup_id": 72,
"order": "self_only"
}
]
Signed-off-by: Hao Luo <haoluo@google.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220829231828.1016835-1-haoluo@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@linux.dev>
There is a potential for us to hit a type conflict when including
netinet/tcp.h and sys/socket.h, we can replace both of these includes
with linux/tcp.h and bpf_tcp_helpers.h to avoid this conflict.
Fixes errors like the below when compiling with gcc BPF backend:
In file included from /usr/include/netinet/tcp.h:91,
from progs/connect4_prog.c:11:
/home/buildroot/opt/cross/lib/gcc/bpf/13.0.0/include/stdint.h:34:23: error: conflicting types for 'int8_t'; have 'char'
34 | typedef __INT8_TYPE__ int8_t;
| ^~~~~~
In file included from /usr/include/x86_64-linux-gnu/sys/types.h:155,
from /usr/include/x86_64-linux-gnu/bits/socket.h:29,
from /usr/include/x86_64-linux-gnu/sys/socket.h:33,
from progs/connect4_prog.c:10:
/usr/include/x86_64-linux-gnu/bits/stdint-intn.h:24:18: note: previous declaration of 'int8_t' with type 'int8_t' {aka 'signed char'}
24 | typedef __int8_t int8_t;
| ^~~~~~
/home/buildroot/opt/cross/lib/gcc/bpf/13.0.0/include/stdint.h:43:24: error: conflicting types for 'int64_t'; have 'long int'
43 | typedef __INT64_TYPE__ int64_t;
| ^~~~~~~
/usr/include/x86_64-linux-gnu/bits/stdint-intn.h:27:19: note: previous declaration of 'int64_t' with type 'int64_t' {aka 'long long int'}
27 | typedef __int64_t int64_t;
| ^~~~~~~
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220829154710.3870139-1-james.hilliard1@gmail.com
There is a potential for us to hit a type conflict when including
netinet/tcp.h with sys/socket.h, we can remove these as they are not
actually needed.
Fixes errors like the below when compiling with gcc BPF backend:
In file included from /usr/include/netinet/tcp.h:91,
from progs/bind4_prog.c:10:
/home/buildroot/opt/cross/lib/gcc/bpf/13.0.0/include/stdint.h:34:23: error: conflicting types for 'int8_t'; have 'char'
34 | typedef __INT8_TYPE__ int8_t;
| ^~~~~~
In file included from /usr/include/x86_64-linux-gnu/sys/types.h:155,
from /usr/include/x86_64-linux-gnu/bits/socket.h:29,
from /usr/include/x86_64-linux-gnu/sys/socket.h:33,
from progs/bind4_prog.c:9:
/usr/include/x86_64-linux-gnu/bits/stdint-intn.h:24:18: note: previous declaration of 'int8_t' with type 'int8_t' {aka 'signed char'}
24 | typedef __int8_t int8_t;
| ^~~~~~
/home/buildroot/opt/cross/lib/gcc/bpf/13.0.0/include/stdint.h:43:24: error: conflicting types for 'int64_t'; have 'long int'
43 | typedef __INT64_TYPE__ int64_t;
| ^~~~~~~
/usr/include/x86_64-linux-gnu/bits/stdint-intn.h:27:19: note: previous declaration of 'int64_t' with type 'int64_t' {aka 'long long int'}
27 | typedef __int64_t int64_t;
| ^~~~~~~
make: *** [Makefile:537: /home/buildroot/bpf-next/tools/testing/selftests/bpf/bpf_gcc/bind4_prog.o] Error 1
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220826052925.980431-1-james.hilliard1@gmail.com
MAX_TAIL_CALL_CNT is 33, so min(MAX_TAIL_CALL_CNT, 0xffff) is always
MAX_TAIL_CALL_CNT, it is better to use MAX_TAIL_CALL_CNT directly.
At the same time, add BUILD_BUG_ON(MAX_TAIL_CALL_CNT > 0xffff) with a
comment on why the assertion is there.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Suggested-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1661742309-2320-1-git-send-email-yangtiezhu@loongson.cn
Due to bpf_map_lookup_elem being declared static we need to also
declare subprog_noise as static.
Fixes the following error:
progs/tailcall_bpf2bpf4.c:26:9: error: 'bpf_map_lookup_elem' is static but used in inline function 'subprog_noise' which is not static [-Werror]
26 | bpf_map_lookup_elem(&nop_table, &key);
| ^~~~~~~~~~~~~~~~~~~
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20220826035141.737919-1-james.hilliard1@gmail.com
The sys/socket.h header isn't required to build test_tc_dtime and may
cause a type conflict.
Fixes the following error:
In file included from /usr/include/x86_64-linux-gnu/sys/types.h:155,
from /usr/include/x86_64-linux-gnu/bits/socket.h:29,
from /usr/include/x86_64-linux-gnu/sys/socket.h:33,
from progs/test_tc_dtime.c:18:
/usr/include/x86_64-linux-gnu/bits/stdint-intn.h:24:18: error: conflicting types for 'int8_t'; have '__int8_t' {aka 'signed char'}
24 | typedef __int8_t int8_t;
| ^~~~~~
In file included from progs/test_tc_dtime.c:5:
/home/buildroot/opt/cross/lib/gcc/bpf/13.0.0/include/stdint.h:34:23: note: previous declaration of 'int8_t' with type 'int8_t' {aka 'char'}
34 | typedef __INT8_TYPE__ int8_t;
| ^~~~~~
/usr/include/x86_64-linux-gnu/bits/stdint-intn.h:27:19: error: conflicting types for 'int64_t'; have '__int64_t' {aka 'long long int'}
27 | typedef __int64_t int64_t;
| ^~~~~~~
/home/buildroot/opt/cross/lib/gcc/bpf/13.0.0/include/stdint.h:43:24: note: previous declaration of 'int64_t' with type 'int64_t' {aka 'long int'}
43 | typedef __INT64_TYPE__ int64_t;
| ^~~~~~~
make: *** [Makefile:537: /home/buildroot/bpf-next/tools/testing/selftests/bpf/bpf_gcc/test_tc_dtime.o] Error 1
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Link: https://lore.kernel.org/r/20220826050703.869571-1-james.hilliard1@gmail.com
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
