Migrate test case from bpf/test_sock_addr.c ensuring that sendmsg
respects when sendmsg6 hooks rewrite the destination IP with the IPv6
wildcard IP, [::].
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240510190246.3247730-10-jrife@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Migrate test case from bpf/test_sock_addr.c ensuring that sendmsg
returns -ENOTSUPP when sending to an IPv4-mapped IPv6 address to
prog_tests/sock_addr.c.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240510190246.3247730-9-jrife@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This set of tests checks that sendmsg calls are rejected (return -EPERM)
when the sendmsg* hook returns 0. Replace those in bpf/test_sock_addr.c
with corresponding tests in prog_tests/sock_addr.c.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240510190246.3247730-8-jrife@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In preparation to move test cases from bpf/test_sock_addr.c that expect
system calls to return ENOTSUPP or EPERM, this patch propagates errno
from relevant system calls up to test_sock_addr() where the result can
be checked.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240510190246.3247730-6-jrife@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In preparation to move test cases from bpf/test_sock_addr.c that expect
ATTACH_REJECT, this patch adds BPF_SKEL_FUNCS_RAW to generate load and
destroy functions that use bpf_prog_attach() to control the attach_type.
The normal load functions use bpf_program__attach_cgroup which does not
have the same degree of control over the attach type, as
bpf_program_attach_fd() calls bpf_link_create() with the attach type
extracted from prog using bpf_program__expected_attach_type(). It is
currently not possible to modify the attach type before
bpf_program__attach_cgroup() is called, since
bpf_program__set_expected_attach_type() has no effect after the program
is loaded.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240510190246.3247730-5-jrife@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In preparation to move test cases from bpf/test_sock_addr.c that expect
LOAD_REJECT, this patch adds expected_attach_type and extends load_fn to
accept an expected attach type and a flag indicating whether or not
rejection is expected.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240510190246.3247730-4-jrife@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In preparation to migrate tests from bpf/test_sock_addr.c to
sock_addr.c, update BPF_SKEL_FUNCS so that it generates functions
based on prog_name instead of skel_name. This allows us to differentiate
between programs in the same skeleton.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240510190246.3247730-3-jrife@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This set of tests check that the BPF verifier rejects programs with
invalid return codes (recvmsg4 and recvmsg6 hooks can only return 1).
This patch replaces the tests in test_sock_addr.c with
verifier_sock_addr.c, a new verifier prog_tests for sockaddr hooks, in a
step towards fully retiring test_sock_addr.c.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240510190246.3247730-2-jrife@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch uses public helper connect_to_fd() exported in network_helpers.h
instead of the local defined function connect_to_server() in
test_tcp_check_syncookie_user.c. This can avoid duplicate code.
Then the arguments "addr" and "len" of run_test() become useless, drop them
too.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/e0ae6b790ac0abc7193aadfb2660c8c9eb0fe1f0.1714907662.git.tanggeliang@kylinos.cn
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This patch uses public helper connect_to_fd() exported in network_helpers.h
instead of the local defined function connect_to_server() in
prog_tests/sockopt_inherit.c. This can avoid duplicate code.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/71db79127cc160b0643fd9a12c70ae019ae076a1.1714907662.git.tanggeliang@kylinos.cn
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Include network_helpers.h in test_tcp_check_syncookie_user.c, use
public helper start_server_addr() in it instead of the local defined
function start_server(). This can avoid duplicate code.
Add two helpers v6only_true() and v6only_false() to set IPV6_V6ONLY
sockopt to true or false, set them to post_socket_cb pointer of struct
network_helper_opts, and pass it to start_server_setsockopt().
In order to use functions defined in network_helpers.c, Makefile needs
to be updated too.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/e0c5324f5da84f453f47543536e70f126eaa8678.1714907662.git.tanggeliang@kylinos.cn
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Include network_helpers.h in prog_tests/sockopt_inherit.c, use public
helper start_server_addr() instead of the local defined function
start_server(). This can avoid duplicate code.
Add a helper custom_cb() to set SOL_CUSTOM sockopt looply, set it to
post_socket_cb pointer of struct network_helper_opts, and pass it to
start_server_addr().
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/687af66f743a0bf15cdba372c5f71fe64863219e.1714907662.git.tanggeliang@kylinos.cn
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
__start_server() sets SO_REUSPORT through setsockopt() when the parameter
'reuseport' is set. This patch makes it more flexible by adding a function
pointer post_socket_cb into struct network_helper_opts. The
'const struct post_socket_opts *cb_opts' args in the post_socket_cb is
for the future extension.
The 'reuseport' parameter can be dropped.
Now the original start_reuseport_server() can be implemented by setting a
newly defined reuseport_cb() function pointer to post_socket_cb filed of
struct network_helper_opts.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/470cb82f209f055fc7fb39c66c6b090b5b7ed2b2.1714907662.git.tanggeliang@kylinos.cn
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The previous patches have consolidated the tests to use
bpf_tracing_net.h (i.e. vmlinux.h) instead of bpf_tcp_helpers.h.
This patch can finally retire the bpf_tcp_helpers.h from
the repository.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-11-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The patch removes the remaining bpf_tcp_helpers.h usages in the
non tcp-cc networking tests. It either replaces it with bpf_tracing_net.h
or just removed it because the test is not actually using any
kernel sockets. For the later, the missing macro (mainly SOL_TCP) is
defined locally.
An exception is the test_sock_fields which is testing
the "struct bpf_sock" type instead of the kernel sock type.
Whenever "vmlinux.h" is used instead, it hits a verifier
error on doing arithmetic on the sock_common pointer:
; return !a6[0] && !a6[1] && !a6[2] && a6[3] == bpf_htonl(1); @ test_sock_fields.c:54
21: (61) r2 = *(u32 *)(r1 +28) ; R1_w=sock_common() R2_w=scalar(smin=0,smax=umax=0xffffffff,var_off=(0x0; 0xffffffff))
22: (56) if w2 != 0x0 goto pc-6 ; R2_w=0
23: (b7) r3 = 28 ; R3_w=28
24: (bf) r2 = r1 ; R1_w=sock_common() R2_w=sock_common()
25: (0f) r2 += r3
R2 pointer arithmetic on sock_common prohibited
Hence, instead of including bpf_tracing_net.h, the test_sock_fields test
defines a tcp_sock with one lsndtime field in it.
Another highlight is, in sockopt_qos_to_cc.c, the tcp_cc_eq()
is replaced by bpf_strncmp(). tcp_cc_eq() was a workaround
in bpf_tcp_helpers.h before bpf_strncmp had been added.
The SOL_IPV6 addition to bpf_tracing_net.h is needed by the
test_tcpbpf_kern test.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-10-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch removed the final few bpf_tcp_helpers.h usages
in some misc bpf tcp-cc tests and replace it with
bpf_tracing_net.h (i.e. vmlinux.h)
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-9-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch uses bpf_tracing_net.h (i.e. vmlinux.h) in bpf_dctcp.
This will allow to retire the bpf_tcp_helpers.h and consolidate
tcp-cc tests to vmlinux.h.
It will have a dup on min/max macros with the bpf_cubic. It could
be further refactored in the future.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-8-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch uses bpf_tracing_net.h (i.e. vmlinux.h) in bpf_cubic.
This will allow to retire the bpf_tcp_helpers.h and consolidate
tcp-cc tests to vmlinux.h.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-7-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The "struct bictcp" and "struct dctcp" are private to the bpf prog
and they are stored in the private buffer in inet_csk(sk)->icsk_ca_priv.
Hence, there is no bpf CO-RE required.
The same struct name exists in the vmlinux.h. To reuse vmlinux.h,
they need to be renamed such that the bpf prog logic will be
immuned from the kernel tcp-cc changes.
This patch adds a "bpf_" prefix to them.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-6-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
It is needed to remove the BPF_STRUCT_OPS usages from the tcp-cc tests
because it is defined in bpf_tcp_helpers.h which is going to be retired.
While at it, this patch consolidates all tcp-cc struct_ops programs to
use the SEC("struct_ops") + BPF_PROG().
It also removes the unnecessary __always_inline usages from the
tcp-cc tests.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-5-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch removes the individual tcp_sk implementations from the
tcp-cc tests. The tcp_sk() implementation from the bpf_tracing_net.h
is reused instead.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-4-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds a few tcp related helper functions to bpf_tracing_net.h.
They will be useful for both tcp-cc and network tracing related
bpf progs. They have already been in the bpf_tcp_helpers.h. This change
is needed to retire the bpf_tcp_helpers.h and consolidate all tests
to vmlinux.h (i.e. bpf_tracing_net.h).
Some of the helpers (tcp_sk and inet_csk) are also defined in
bpf_cc_cubic.c and they are removed. While at it, remove
the vmlinux.h from bpf_cc_cubic.c. bpf_tracing_net.h (which has
vmlinux.h after this patch) is enough and will be consistent
with the other tcp-cc tests in the later patches.
The other TCP_* macro additions will be needed for the bpf_dctcp
changes in the later patch.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-3-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch removes the bpf_tracing_net.h usage from the networking tests,
fib_lookup and test_lwt_redirect. Instead of using the (copied) macro
TC_ACT_SHOT and ETH_HLEN from bpf_tracing_net.h, they can directly
use the ones defined in the network header files under linux/.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509175026.3423614-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
[Changes from V1:
- Use a default branch in the switch statement to initialize `val'.]
GCC warns that `val' may be used uninitialized in the
BPF_CRE_READ_BITFIELD macro, defined in bpf_core_read.h as:
[...]
unsigned long long val; \
[...] \
switch (__CORE_RELO(s, field, BYTE_SIZE)) { \
case 1: val = *(const unsigned char *)p; break; \
case 2: val = *(const unsigned short *)p; break; \
case 4: val = *(const unsigned int *)p; break; \
case 8: val = *(const unsigned long long *)p; break; \
} \
[...]
val; \
} \
This patch adds a default entry in the switch statement that sets
`val' to zero in order to avoid the warning, and random values to be
used in case __builtin_preserve_field_info returns unexpected values
for BPF_FIELD_BYTE_SIZE.
Tested in bpf-next master.
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240508101313.16662-1-jose.marchesi@oracle.com
[Changes from V2:
- no-strict-aliasing is only applied when building with GCC.
- cpumask_failure.c is excluded, as it doesn't use __imm_insn.]
The __imm_insn macro is defined in bpf_misc.h as:
#define __imm_insn(name, expr) [name]"i"(*(long *)&(expr))
This may lead to type-punning and strict aliasing rules violations in
it's typical usage where the address of a struct bpf_insn is passed as
expr, like in:
__imm_insn(st_mem,
BPF_ST_MEM(BPF_W, BPF_REG_1, offsetof(struct __sk_buff, mark), 42))
Where:
#define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
((struct bpf_insn) { \
.code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
.dst_reg = DST, \
.src_reg = 0, \
.off = OFF, \
.imm = IMM })
In all the actual instances of this in the BPF selftests the value is
fed to a volatile asm statement as soon as it gets read from memory,
and thus it is unlikely anti-aliasing rules breakage may lead to
misguided optimizations.
However, GCC detects the potential problem (indirectly) by issuing a
warning stating that a temporary <Uxxxxxx> is used uninitialized,
where the temporary corresponds to the memory read by *(long *).
This patch adds -fno-strict-aliasing to the compilation flags of the
particular selftests that do type punning via __imm_insn, only for
GCC.
Tested in master bpf-next.
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Cc: david.faust@oracle.com
Cc: cupertino.miranda@oracle.com
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240508103551.14955-1-jose.marchesi@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
[Changes from V1:
- The warning to disable is -Wmaybe-uninitialized, not -Wuninitialized.
- This warning is only supported in GCC.]
The BPF selftest verifier_global_subprogs.c contains code that
purposedly performs out of bounds access to memory, to check whether
the kernel verifier is able to catch them. For example:
__noinline int global_unsupp(const int *mem)
{
if (!mem)
return 0;
return mem[100]; /* BOOM */
}
With -O1 and higher and no inlining, GCC notices this fact and emits a
"maybe uninitialized" warning. This is by design. Note that the
emission of these warnings is highly dependent on the precise
optimizations that are performed.
This patch adds a compiler pragma to verifier_global_subprogs.c to
ignore these warnings.
Tested in bpf-next master.
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Cc: david.faust@oracle.com
Cc: cupertino.miranda@oracle.com
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240507184756.1772-1-jose.marchesi@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When LSE atomics are available, BPF atomic instructions are implemented
as single ARM64 atomic instructions, therefore it is easy to enable
these in bpf_arena using the currently available exception handling
setup.
LL_SC atomics use loops and therefore would need more work to enable in
bpf_arena.
Enable LSE atomics based instructions in bpf_arena and use the
bpf_jit_supports_insn() callback to reject atomics in bpf_arena if LSE
atomics are not available.
All atomics and arena_atomics selftests are passing:
[root@ip-172-31-2-216 bpf]# ./test_progs -a atomics,arena_atomics
#3/1 arena_atomics/add:OK
#3/2 arena_atomics/sub:OK
#3/3 arena_atomics/and:OK
#3/4 arena_atomics/or:OK
#3/5 arena_atomics/xor:OK
#3/6 arena_atomics/cmpxchg:OK
#3/7 arena_atomics/xchg:OK
#3 arena_atomics:OK
#10/1 atomics/add:OK
#10/2 atomics/sub:OK
#10/3 atomics/and:OK
#10/4 atomics/or:OK
#10/5 atomics/xor:OK
#10/6 atomics/cmpxchg:OK
#10/7 atomics/xchg:OK
#10 atomics:OK
Summary: 2/14 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20240426161116.441-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a simple test that validates that libbpf will reject isolated
struct_ops program early with helpful warning message.
Also validate that explicit use of such BPF program through BPF skeleton
after BPF object is open won't trigger any warnings.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-7-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Extend libbpf's pre-load checks for BPF programs, detecting more typical
conditions that are destinated to cause BPF program failure. This is an
opportunity to provide more helpful and actionable error message to
users, instead of potentially very confusing BPF verifier log and/or
error.
In this case, we detect struct_ops BPF program that was not referenced
anywhere, but still attempted to be loaded (according to libbpf logic).
Suggest that the program might need to be used in some struct_ops
variable. User will get a message of the following kind:
libbpf: prog 'test_1_forgotten': SEC("struct_ops") program isn't referenced anywhere, did you forget to use it?
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-6-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
strerror_r(), used from libbpf-specific libbpf_strerror_r() wrapper is
documented to return error in two different ways, depending on glibc
version. Take that into account when handling strerror_r()'s own errors,
which happens when we pass some non-standard (internal) kernel error to
it. Before this patch we'd have "ERROR: strerror_r(524)=22", which is
quite confusing. Now for the same situation we'll see a bit less
visually scary "unknown error (-524)".
At least we won't confuse user with irrelevant EINVAL (22).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-5-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Add a test which tests the case that was just fixed. Kernel has full
type information about callback, but user explicitly nulls out the
reference to declaratively set BPF program reference.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-4-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
There is yet another corner case where user can set STRUCT_OPS program
reference in STRUCT_OPS map to NULL, but libbpf will fail to disable
autoload for such BPF program. This time it's the case of "new" kernel
which has type information about callback field, but user explicitly
nulled-out program reference from user-space after opening BPF object.
Fix, hopefully, the last remaining unhandled case.
Fixes: 0737df6de9 ("libbpf: better fix for handling nulled-out struct_ops program")
Fixes: f973fccd43 ("libbpf: handle nulled-out program in struct_ops correctly")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-3-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
libbpf ensures that BPF program references set in map->st_ops->progs[i]
during open phase are always valid STRUCT_OPS programs. This is done in
bpf_object__collect_st_ops_relos(). So there is no need to double-check
that in bpf_map__init_kern_struct_ops().
Simplify the code by removing unnecessary check. Also, we avoid using
local prog variable to keep code similar to the upcoming fix, which adds
similar logic in another part of bpf_map__init_kern_struct_ops().
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-2-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The test_xdp_noinline.c contains 2 functions that use more then 5
arguments. This patch collapses the 2 last arguments in an array.
Also in GCC and ipa_sra optimization increases the number of arguments
used in function encap_v4. This pass disables the optimization for that
particular file.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240507122220.207820-3-cupertino.miranda@oracle.com
This patch adds support to specify CFLAGS per source file and per test
runner.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240507122220.207820-2-cupertino.miranda@oracle.com
The vmlinux.h file generated by bpftool makes use of compiler pragmas
in order to install the CO-RE preserve_access_index in all the struct
types derived from the BTF info:
#ifndef __VMLINUX_H__
#define __VMLINUX_H__
#ifndef BPF_NO_PRESERVE_ACCESS_INDEX
#pragma clang attribute push (__attribute__((preserve_access_index)), apply_t = record
#endif
[... type definitions generated from kernel BTF ... ]
#ifndef BPF_NO_PRESERVE_ACCESS_INDEX
#pragma clang attribute pop
#endif
The `clang attribute push/pop' pragmas are specific to clang/llvm and
are not supported by GCC.
At the moment the BTF dumping services in libbpf do not support
dicriminating between types dumped because they are directly referred
and types dumped because they are dependencies. A suitable API is
being worked now. See [1] and [2].
In the interim, this patch changes the selftests/bpf Makefile so it
passes -DBPF_NO_PRESERVE_ACCESS_INDEX to GCC when it builds the
selftests. This workaround is temporary, and may have an impact on
the results of the GCC-built tests.
[1] https://lore.kernel.org/bpf/20240503111836.25275-1-jose.marchesi@oracle.com/T/#u
[2] https://lore.kernel.org/bpf/20240504205510.24785-1-jose.marchesi@oracle.com/T/#u
Tested in bpf-next master.
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240507095011.15867-1-jose.marchesi@oracle.com
This patch modifies selftests/bpf/Makefile to pass -Wno-attributes to
GCC. This is because of the following attributes which are ignored:
- btf_decl_tag
- btf_type_tag
There are many of these. At the moment none of these are
recognized/handled by gcc-bpf.
We are aware that btf_decl_tag is necessary for some of the
selftest harness to communicate test failure/success. Support for
it is in progress in GCC upstream:
https://gcc.gnu.org/pipermail/gcc-patches/2024-May/650482.html
However, the GCC master branch is not yet open, so the series
above (currently under review upstream) wont be able to make it
there until 14.1 gets released, probably mid next week.
As for btf_type_tag, more extensive work will be needed in GCC
upstream to support it in both BTF and DWARF. We have a WIP big
patch for that, but that is not needed to compile/build the
selftests.
- used
There are SEC macros defined in the selftests as:
#define SEC(N) __attribute__((section(N),used))
The SEC macro is used for both functions and global variables.
According to the GCC documentation `used' attribute is really only
meaningful for functions, and it warns when the attribute is used
for other global objects, like for example ctl_array in
test_xdp_noinline.c.
Ignoring this is benign.
- align_value
In progs/test_cls_redirect.c:127 there is:
typedef uint8_t *net_ptr __attribute__((align_value(8)));
GCC warns that it is ignoring this attribute, because it is not
implemented by GCC.
I think ignoring this attribute in GCC is benign, because according
to the clang documentation [1] its purpose seems to be merely
declarative and doesn't seem to translate into extra checks at
run-time, only to perhaps better optimized code ("runtime behavior
is undefined if the pointed memory object is not aligned to the
specified alignment").
[1] https://clang.llvm.org/docs/AttributeReference.html#align-value
Tested in bpf-next master.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240507074227.4523-3-jose.marchesi@oracle.com
An object defined as `static' defaults to hidden visibility. If
additionally the visibility(__weak__) compiler attribute is applied to
the declaration of the object, GCC warns that the attribute gets
ignored.
This patch removes the only instance of this problem among the BPF
selftests.
Tested in bpf-next master.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240507074227.4523-2-jose.marchesi@oracle.com
Added a test for bound computation in MUL when non constant
values are used and both registers have bounded ranges.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Link: https://lore.kernel.org/r/20240506141849.185293-7-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Added a test for bound computation in XOR and OR when non constant
values are used and both registers have bounded ranges.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Link: https://lore.kernel.org/r/20240506141849.185293-5-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When building either tools/bpf/bpftool, or tools/testing/selftests/hid,
(the same Makefile is used for these), clang generates many instances of
the following:
"clang: warning: -lLLVM-17: 'linker' input unused"
Quentin points out that the LLVM version is only required in $(LIBS),
not in $(CFLAGS), so the fix is to remove it from CFLAGS.
Suggested-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/bpf/20240505230054.13813-1-jhubbard@nvidia.com
Cast operation has a higher precedence than addition. The code here
wants to zero the 2nd half of the 64-bit metadata, but due to a pointer
arithmetic mistake, it writes the zero at offset 16 instead.
Just adding parentheses around "data + 4" would fix this, but I think
this will be slightly better readable with array syntax.
I was unable to test this with tools/testing/selftests/bpf/vmtest.sh,
because my glibc is newer than glibc in the provided VM image.
So I just checked the difference in the compiled code.
objdump -S tools/testing/selftests/bpf/xdp_do_redirect.test.o:
- *((__u32 *)data) = 0x42; /* metadata test value */
+ ((__u32 *)data)[0] = 0x42; /* metadata test value */
be7: 48 8d 85 30 fc ff ff lea -0x3d0(%rbp),%rax
bee: c7 00 42 00 00 00 movl $0x42,(%rax)
- *((__u32 *)data + 4) = 0;
+ ((__u32 *)data)[1] = 0;
bf4: 48 8d 85 30 fc ff ff lea -0x3d0(%rbp),%rax
- bfb: 48 83 c0 10 add $0x10,%rax
+ bfb: 48 83 c0 04 add $0x4,%rax
bff: c7 00 00 00 00 00 movl $0x0,(%rax)
Fixes: 5640b6d894 ("selftests/bpf: fix "metadata marker" getting overwritten by the netstack")
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20240506145023.214248-1-mschmidt@redhat.com
The bpf programs that this patch changes require the BPF_PROG macro.
The BPF_PROG macro is defined in the libbpf's bpf_tracing.h.
Some tests include bpf_tcp_helpers.h which includes bpf_tracing.h.
They don't need other things from bpf_tcp_helpers.h other than
bpf_tracing.h. This patch simplifies it by directly including
the bpf_tracing.h.
The motivation of this unnecessary code churn is to retire
the bpf_tcp_helpers.h by directly using vmlinux.h. Right now,
the main usage of the bpf_tcp_helpers.h is the partial kernel
socket definitions (e.g. socket, sock, tcp_sock). While the test
cases continue to grow, fields are kept adding to those partial
socket definitions (e.g. the recent bpf_cc_cubic.c test which
tried to extend bpf_tcp_helpers.c but eventually used the
vmlinux.h instead).
The idea is to retire bpf_tcp_helpers.c and consistently use
vmlinux.h for the tests that require the kernel sockets. This
patch tackles the obvious tests that can directly use bpf_tracing.h
instead of bpf_tcp_helpers.h.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240504005045.848376-1-martin.lau@linux.dev
[Differences from V1:
- Do not introduce a global typedef, as this is a public header.
- Keep the void* casts in BPF_KPROBE_READ_RET_IP and
BPF_KRETPROBE_READ_RET_IP, as these are necessary
for converting to a const void* argument of
bpf_probe_read_kernel.]
The BPF_PROG, BPF_KPROBE and BPF_KSYSCALL macros defined in
tools/lib/bpf/bpf_tracing.h use a clever hack in order to provide a
convenient way to define entry points for BPF programs as if they were
normal C functions that get typed actual arguments, instead of as
elements in a single "context" array argument.
For example, PPF_PROGS allows writing:
SEC("struct_ops/cwnd_event")
void BPF_PROG(cwnd_event, struct sock *sk, enum tcp_ca_event event)
{
bbr_cwnd_event(sk, event);
dctcp_cwnd_event(sk, event);
cubictcp_cwnd_event(sk, event);
}
That expands into a pair of functions:
void ____cwnd_event (unsigned long long *ctx, struct sock *sk, enum tcp_ca_event event)
{
bbr_cwnd_event(sk, event);
dctcp_cwnd_event(sk, event);
cubictcp_cwnd_event(sk, event);
}
void cwnd_event (unsigned long long *ctx)
{
_Pragma("GCC diagnostic push")
_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")
return ____cwnd_event(ctx, (void*)ctx[0], (void*)ctx[1]);
_Pragma("GCC diagnostic pop")
}
Note how the 64-bit unsigned integers in the incoming CTX get casted
to a void pointer, and then implicitly converted to whatever type of
the actual argument in the wrapped function. In this case:
Arg1: unsigned long long -> void * -> struct sock *
Arg2: unsigned long long -> void * -> enum tcp_ca_event
The behavior of GCC and clang when facing such conversions differ:
pointer -> pointer
Allowed by the C standard.
GCC: no warning nor error.
clang: no warning nor error.
pointer -> integer type
[C standard says the result of this conversion is implementation
defined, and it may lead to unaligned pointer etc.]
GCC: error: integer from pointer without a cast [-Wint-conversion]
clang: error: incompatible pointer to integer conversion [-Wint-conversion]
pointer -> enumerated type
GCC: error: incompatible types in assigment (*)
clang: error: incompatible pointer to integer conversion [-Wint-conversion]
These macros work because converting pointers to pointers is allowed,
and converting pointers to integers also works provided a suitable
integer type even if it is implementation defined, much like casting a
pointer to uintptr_t is guaranteed to work by the C standard. The
conversion errors emitted by both compilers by default are silenced by
the pragmas.
However, the GCC error marked with (*) above when assigning a pointer
to an enumerated value is not associated with the -Wint-conversion
warning, and it is not possible to turn it off.
This is preventing building the BPF kernel selftests with GCC.
This patch fixes this by avoiding intermediate casts to void*,
replaced with casts to `unsigned long long', which is an integer type
capable of safely store a BPF pointer, much like the standard
uintptr_t.
Testing performed in bpf-next master:
- vmtest.sh -- ./test_verifier
- vmtest.sh -- ./test_progs
- make M=samples/bpf
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240502170925.3194-1-jose.marchesi@oracle.com
The macro bpf_ksym_exists is defined in bpf_helpers.h as:
#define bpf_ksym_exists(sym) ({ \
_Static_assert(!__builtin_constant_p(!!sym), #sym " should be marked as __weak"); \
!!sym; \
})
The purpose of the macro is to determine whether a given symbol has
been defined, given the address of the object associated with the
symbol. It also has a compile-time check to make sure the object
whose address is passed to the macro has been declared as weak, which
makes the check on `sym' meaningful.
As it happens, the check for weak doesn't work in GCC in all cases,
because __builtin_constant_p not always folds at parse time when
optimizing. This is because optimizations that happen later in the
compilation process, like inlining, may make a previously non-constant
expression a constant. This results in errors like the following when
building the selftests with GCC:
bpf_helpers.h:190:24: error: expression in static assertion is not constant
190 | _Static_assert(!__builtin_constant_p(!!sym), #sym " should be marked as __weak"); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fortunately recent versions of GCC support a __builtin_has_attribute
that can be used to directly check for the __weak__ attribute. This
patch changes bpf_helpers.h to use that builtin when building with a
recent enough GCC, and to omit the check if GCC is too old to support
the builtin.
The macro used for GCC becomes:
#define bpf_ksym_exists(sym) ({ \
_Static_assert(__builtin_has_attribute (*sym, __weak__), #sym " should be marked as __weak"); \
!!sym; \
})
Note that since bpf_ksym_exists is designed to get the address of the
object associated with symbol SYM, we pass *sym to
__builtin_has_attribute instead of sym. When an expression is passed
to __builtin_has_attribute then it is the type of the passed
expression that is checked for the specified attribute. The
expression itself is not evaluated. This accommodates well with the
existing usages of the macro:
- For function objects:
struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym __weak;
[...]
bpf_ksym_exists(bpf_task_acquire)
- For variable objects:
extern const struct rq runqueues __ksym __weak; /* typed */
[...]
bpf_ksym_exists(&runqueues)
Note also that BPF support was added in GCC 10 and support for
__builtin_has_attribute in GCC 9.
Locally tested in bpf-next master branch.
No regressions.
Signed-of-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240428112559.10518-1-jose.marchesi@oracle.com
Add INT_MAX check to ring_buffer__consume_n(). We do the similar check
to handle int return result of all these ring buffer APIs in other APIs
and ring_buffer__consume_n() is missing one. This patch fixes this
omission.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240430201952.888293-2-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
