Before this series the verifier would clamp return bounds of
bpf_get_stack() to [0, X] and this led the verifier to believe
that a JMP_JSLT 0 would be false and so would prune that path.
The result is anything hidden behind that JSLT would be unverified.
Add a test to catch this case by hiding an goto pc-1 behind the
check which will cause an infinite loop if not rejected.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/158560423908.10843.11783152347709008373.stgit@john-Precision-5820-Tower
Add support for testing UDP sk_assign to the existing tests.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Lorenz Bauer <lmb@cloudflare.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200329225342.16317-6-joe@wand.net.nz
Attach a tc direct-action classifier to lo in a fresh network
namespace, and rewrite all connection attempts to localhost:4321
to localhost:1234 (for port tests) and connections to unreachable
IPv4/IPv6 IPs to the local socket (for address tests). Includes
implementations for both TCP and UDP.
Keep in mind that both client to server and server to client traffic
passes the classifier.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200329225342.16317-5-joe@wand.net.nz
Co-authored-by: Joe Stringer <joe@wand.net.nz>
* Load/attach a BPF program that hooks to file_mprotect (int)
and bprm_committed_creds (void).
* Perform an action that triggers the hook.
* Verify if the audit event was received using the shared global
variables for the process executed.
* Verify if the mprotect returns a -EPERM.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Florent Revest <revest@google.com>
Reviewed-by: Thomas Garnier <thgarnie@google.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200329004356.27286-8-kpsingh@chromium.org
This adds a test to exercise the new bpf_map__set_initial_value() function.
The test simply overrides the global data section with all zeroes, and
checks that the new value makes it into the kernel map on load.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200329132253.232541-2-toke@redhat.com
This patch adds test to exercise the bpf_sk_storage_get()
and bpf_sk_storage_delete() helper from the bpf_dctcp.c.
The setup and check on the sk_storage is done immediately
before and after the connect().
This patch also takes this chance to move the pthread_create()
after the connect() has been done. That will remove the need of
the "wait_thread" label.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200320152107.2169904-1-kafai@fb.com
Remove unused len variable, which causes compilation warnings.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200314001834.3727680-1-andriin@fb.com
Add vmlinux.h generation to selftest/bpf's Makefile. Use it from newly added
test_vmlinux to trace nanosleep syscall using 5 different types of programs:
- tracepoint;
- raw tracepoint;
- raw tracepoint w/ direct memory reads (tp_btf);
- kprobe;
- fentry.
These programs are realistic variants of real-life tracing programs,
excercising vmlinux.h's usage with tracing applications.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200313172336.1879637-5-andriin@fb.com
Introduce new helper that reuses existing xdp perf_event output
implementation, but can be called from raw_tracepoint programs
that receive 'struct xdp_buff *' as a tracepoint argument.
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158348514556.2239.11050972434793741444.stgit@xdp-tutorial
Test for two scenarios:
* When the fmod_ret program returns 0, the original function should
be called along with fentry and fexit programs.
* When the fmod_ret program returns a non-zero value, the original
function should not be called, no side effect should be observed and
fentry and fexit programs should be called.
The result from the kernel function call and whether a side-effect is
observed is returned via the retval attr of the BPF_PROG_TEST_RUN (bpf)
syscall.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200304191853.1529-8-kpsingh@chromium.org
Currently, BTF_KIND_ENUM type doesn't record whether enum values should be
interpreted as signed or unsigned. In Linux, most enums are unsigned, though,
so interpreting them as unsigned matches real world better.
Change btf_dump test case to test maximum 32-bit value, instead of negative
value.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200303003233.3496043-3-andriin@fb.com
Move BPF_PROG, BPF_KPROBE, and BPF_KRETPROBE macro into libbpf's bpf_tracing.h
header to make it available for non-selftests users.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200229231112.1240137-5-andriin@fb.com
For kretprobes, there is no point in capturing input arguments from pt_regs,
as they are going to be, most probably, clobbered by the time probed kernel
function returns. So switch BPF_KRETPROBE to accept zero or one argument
(optional return result).
Fixes: ac065870d9 ("selftests/bpf: Add BPF_PROG, BPF_KPROBE, and BPF_KRETPROBE macros")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200229231112.1240137-4-andriin@fb.com
Now that SOCKMAP and SOCKHASH map types can store listening sockets,
user-space and BPF API is open to a new set of potential pitfalls.
Exercise the map operations, with extra attention to code paths susceptible
to races between map ops and socket cloning, and BPF helpers that work with
SOCKMAP/SOCKHASH to gain confidence that all works as expected.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200218171023.844439-12-jakub@cloudflare.com
Use the new bpf_program__set_attach_target() API in the xdp_bpf2bpf
selftest so it can be referenced as an example on how to use it.
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/158220520562.127661.14289388017034825841.stgit@xdp-tutorial
Add a selftest to test:
* default bpf_read_branch_records() behavior
* BPF_F_GET_BRANCH_RECORDS_SIZE flag behavior
* error path on non branch record perf events
* using helper to write to stack
* using helper to write to global
On host with hardware counter support:
# ./test_progs -t perf_branches
#27/1 perf_branches_hw:OK
#27/2 perf_branches_no_hw:OK
#27 perf_branches:OK
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
On host without hardware counter support (VM):
# ./test_progs -t perf_branches
#27/1 perf_branches_hw:OK
#27/2 perf_branches_no_hw:OK
#27 perf_branches:OK
Summary: 1/2 PASSED, 1 SKIPPED, 0 FAILED
Also sync tools/include/uapi/linux/bpf.h.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200218030432.4600-3-dxu@dxuuu.xyz
There's limit of 40 programs tht can be attached
to trampoline for one function. Adding test that
tries to attach that many plus one extra that needs
to fail.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200123161508.915203-4-jolsa@kernel.org
The reuseport tests currently suffer from a race condition: FIN
packets count towards DROP_ERR_SKB_DATA, since they don't contain
a valid struct cmd. Tests will spuriously fail depending on whether
check_results is called before or after the FIN is processed.
Exit the BPF program early if FIN is set.
Fixes: 91134d849a ("bpf: Test BPF_PROG_TYPE_SK_REUSEPORT")
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200124112754.19664-3-lmb@cloudflare.com
This patch adds a bpf_cubic example. Some highlights:
1. CONFIG_HZ .kconfig map is used.
2. In bictcp_update(), calculation is changed to use usec
resolution (i.e. USEC_PER_JIFFY) instead of using jiffies.
Thus, usecs_to_jiffies() is not used in the bpf_cubic.c.
3. In bitctcp_update() [under tcp_friendliness], the original
"while (ca->ack_cnt > delta)" loop is changed to the equivalent
"ca->ack_cnt / delta" operation.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200122233658.903774-1-kafai@fb.com
Add program extension tests that build on top of fexit_bpf2bpf tests.
Replace three global functions in previously loaded test_pkt_access.c program
with three new implementations:
int get_skb_len(struct __sk_buff *skb);
int get_constant(long val);
int get_skb_ifindex(int val, struct __sk_buff *skb, int var);
New function return the same results as original only if arguments match.
new_get_skb_ifindex() demonstrates that 'skb' argument doesn't have to be first
and only argument of BPF program. All normal skb based accesses are available.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200121005348.2769920-4-ast@kernel.org
Fix all selftests to include libbpf header files with the bpf/ prefix, to
be consistent with external users of the library. Also ensure that all
includes of exported libbpf header files (those that are exported on 'make
install' of the library) use bracketed includes instead of quoted.
To not break the build, keep the old include path until everything has been
changed to the new one; a subsequent patch will remove that.
Fixes: 6910d7d386 ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157952560568.1683545.9649335788846513446.stgit@toke.dk
Add a test that will attach a FENTRY and FEXIT program to the XDP test
program. It will also verify data from the XDP context on FENTRY and
verifies the return code on exit.
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157909410480.47481.11202505690938004673.stgit@xdp-tutorial
The test_progs send_signal() is amended to test
bpf_send_signal_thread() as well.
$ ./test_progs -n 40
#40/1 send_signal_tracepoint:OK
#40/2 send_signal_perf:OK
#40/3 send_signal_nmi:OK
#40/4 send_signal_tracepoint_thread:OK
#40/5 send_signal_perf_thread:OK
#40/6 send_signal_nmi_thread:OK
#40 send_signal:OK
Summary: 1/6 PASSED, 0 SKIPPED, 0 FAILED
Also took this opportunity to rewrite the send_signal test
using skeleton framework and array mmap to make code
simpler and more readable.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200115035003.602425-1-yhs@fb.com
Streamline BPF_TRACE_x macro by moving out return type and section attribute
definition out of macro itself. That makes those function look in source code
similar to other BPF programs. Additionally, simplify its usage by determining
number of arguments automatically (so just single BPF_TRACE vs a family of
BPF_TRACE_1, BPF_TRACE_2, etc). Also, allow more natural function argument
syntax without commas inbetween argument type and name.
Given this helper is useful not only for tracing tp_btf/fenty/fexit programs,
but could be used for LSM programs and others following the same pattern,
rename BPF_TRACE macro into more generic BPF_PROG. Existing BPF_TRACE_x
usages in selftests are converted to new BPF_PROG macro.
Following the same pattern, define BPF_KPROBE and BPF_KRETPROBE macros for
nicer usage of kprobe/kretprobe arguments, respectively. BPF_KRETPROBE, adopts
same convention used by fexit programs, that last defined argument is probed
function's return result.
v4->v5:
- fix test_overhead test (__set_task_comm is void) (Alexei);
v3->v4:
- rebased and fixed one more BPF_TRACE_x occurence (Alexei);
v2->v3:
- rename to shorter and as generic BPF_PROG (Alexei);
v1->v2:
- verified GCC handles pragmas as expected;
- added descriptions to macros;
- converted new STRUCT_OPS selftest to BPF_HANDLER (worked as expected);
- added original context as 'ctx' parameter, for cases where it has to be
passed into BPF helpers. This might cause an accidental naming collision,
unfortunately, but at least it's easy to work around. Fortunately, this
situation produces quite legible compilation error:
progs/bpf_dctcp.c:46:6: error: redefinition of 'ctx' with a different type: 'int' vs 'unsigned long long *'
int ctx = 123;
^
progs/bpf_dctcp.c:42:6: note: previous definition is here
void BPF_HANDLER(dctcp_init, struct sock *sk)
^
./bpf_trace_helpers.h:58:32: note: expanded from macro 'BPF_HANDLER'
____##name(unsigned long long *ctx, ##args)
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200110211634.1614739-1-andriin@fb.com
test_global_func[12] - check 512 stack limit.
test_global_func[34] - check 8 frame call chain limit.
test_global_func5 - check that non-ctx pointer cannot be passed into
a function that expects context.
test_global_func6 - check that ctx pointer is unmodified.
test_global_func7 - check that global function returns scalar.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200110064124.1760511-7-ast@kernel.org
Make two static functions in test_xdp_noinline.c global:
before: processed 2790 insns
after: processed 2598 insns
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200110064124.1760511-6-ast@kernel.org
test results:
pyperf50 with always_inlined the same function five times: processed 46378 insns
pyperf50 with global function: processed 6102 insns
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200110064124.1760511-5-ast@kernel.org
Add simple fexit prog type to skb prog type test when subprogram is a global
function.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200110064124.1760511-4-ast@kernel.org
This patch adds a bpf_dctcp example. It currently does not do
no-ECN fallback but the same could be done through the cgrp2-bpf.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200109003517.3856825-1-kafai@fb.com
allow to pass skb's mark field into bpf_prog_test_run ctx
for BPF_PROG_TYPE_SCHED_CLS prog type. that would allow
to test bpf programs which are doing decision based on this
field
Signed-off-by: Nikita V. Shirokov <tehnerd@tehnerd.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a set of tests validating libbpf-provided extern variables. One crucial
feature that's tested is dead code elimination together with using invalid BPF
helper. CONFIG_MISSING is not supposed to exist and should always be specified
by libbpf as zero, which allows BPF verifier to correctly do branch pruning
and not fail validation, when invalid BPF helper is called from dead if branch.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191214014710.3449601-5-andriin@fb.com
Add a simple selftests validating datasection-to-struct layour dumping. Global
variables are constructed in such a way as to cause both natural and
artificial padding (through custom alignment requirement).
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-17-andriin@fb.com
Make sure we can pass arbitrary data in wire_len/gso_segs.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191213223028.161282-2-sdf@google.com
Now that libbpf can recognize SK_REUSEPORT programs, we no longer have to
pass a prog_type hint before loading the object file.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191212102259.418536-3-jakub@cloudflare.com
The existing fexit_bpf2bpf test covers the target progrm with callees.
This patch added a test for the target program without callees.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191205010607.177904-1-yhs@fb.com
It looks like BPF program that handles BPF_SOCK_OPS_STATE_CB state
can race with the bpf_map_lookup_elem("global_map"); I sometimes
see the failures in this test and re-running helps.
Since we know that we expect the callback to be called 3 times (one
time for listener socket, two times for both ends of the connection),
let's export this number and add simple retry logic around that.
Also, let's make EXPECT_EQ() not return on failure, but continue
evaluating all conditions; that should make potential debugging
easier.
With this fix in place I don't observe the flakiness anymore.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Lawrence Brakmo <brakmo@fb.com>
Link: https://lore.kernel.org/bpf/20191204190955.170934-1-sdf@google.com
Similarly to a0d7da26ce ("libbpf: Fix call relocation offset calculation
bug"), relocations against global variables need to take into account
referenced symbol's st_value, which holds offset into a corresponding data
section (and, subsequently, offset into internal backing map). For static
variables this offset is always zero and data offset is completely described
by respective instruction's imm field.
Convert a bunch of selftests to global variables. Previously they were relying
on `static volatile` trick to ensure Clang doesn't inline static variables,
which with global variables is not necessary anymore.
Fixes: 393cdfbee8 ("libbpf: Support initialized global variables")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191127200651.1381348-1-andriin@fb.com
For BPF_PROG_TYPE_TRACING, the bpf_prog's ctx is an array of u64.
This patch borrows the idea from BPF_CALL_x in filter.h to
convert a u64 to the arg type of the traced function.
The new BPF_TRACE_x has an arg to specify the return type of a bpf_prog.
It will be used in the future TCP-ops bpf_prog that may return "void".
The new macros are defined in the new header file "bpf_trace_helpers.h".
It is under selftests/bpf/ for now. It could be moved to libbpf later
after seeing more upcoming non-tracing use cases.
The tests are changed to use these new macros also. Hence,
the k[s]u8/16/32/64 are no longer needed and they are removed
from the bpf_helpers.h.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191123202504.1502696-1-kafai@fb.com
Add several BPF kselftest cases for tail calls which test the various
patch directions, and that multiple locations are patched in same and
different programs.
# ./test_progs -n 45
#45/1 tailcall_1:OK
#45/2 tailcall_2:OK
#45/3 tailcall_3:OK
#45/4 tailcall_4:OK
#45/5 tailcall_5:OK
#45 tailcalls:OK
Summary: 1/5 PASSED, 0 SKIPPED, 0 FAILED
I've also verified the JITed dump after each of the rewrite cases that
it matches expectations.
Also regular test_verifier suite passes fine which contains further tail
call tests:
# ./test_verifier
[...]
Summary: 1563 PASSED, 0 SKIPPED, 0 FAILED
Checked under JIT, interpreter and JIT + hardening.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/3d6cbecbeb171117dccfe153306e479798fb608d.1574452833.git.daniel@iogearbox.net
Add a test that benchmarks different ways of attaching BPF program to a kernel function.
Here are the results for 2.4Ghz x86 cpu on a kernel without mitigations:
$ ./test_progs -n 49 -v|grep events
task_rename base 2743K events per sec
task_rename kprobe 2419K events per sec
task_rename kretprobe 1876K events per sec
task_rename raw_tp 2578K events per sec
task_rename fentry 2710K events per sec
task_rename fexit 2685K events per sec
On a kernel with retpoline:
$ ./test_progs -n 49 -v|grep events
task_rename base 2401K events per sec
task_rename kprobe 1930K events per sec
task_rename kretprobe 1485K events per sec
task_rename raw_tp 2053K events per sec
task_rename fentry 2351K events per sec
task_rename fexit 2185K events per sec
All 5 approaches:
- kprobe/kretprobe in __set_task_comm()
- raw tracepoint in trace_task_rename()
- fentry/fexit in __set_task_comm()
are roughly equivalent.
__set_task_comm() by itself is quite fast, so any extra instructions add up.
Until BPF trampoline was introduced the fastest mechanism was raw tracepoint.
kprobe via ftrace was second best. kretprobe is slow due to trap. New
fentry/fexit methods via BPF trampoline are clearly the fastest and the
difference is more pronounced with retpoline on, since BPF trampoline doesn't
use indirect jumps.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20191122011515.255371-1-ast@kernel.org
test_core_reloc_kernel.c selftest is the only CO-RE test that reads and
returns for validation calling thread's information (pid, tgid, comm). Thus it
has to make sure that only test_prog's invocations are honored.
Fixes: df36e62141 ("selftests/bpf: add CO-RE relocs testing setup")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20191121175900.3486133-1-andriin@fb.com
Initialized global variables are no different in ELF from static variables,
and don't require any extra support from libbpf. But they are matching
semantics of global data (backed by BPF maps) more closely, preventing
LLVM/Clang from aggressively inlining constant values and not requiring
volatile incantations to prevent those. This patch enables global variables.
It still disables uninitialized variables, which will be put into special COM
(common) ELF section, because BPF doesn't allow uninitialized data to be
accessed.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191121070743.1309473-5-andriin@fb.com
Currently, with latest llvm trunk, selftest test_progs failed obj
file test_seg6_loop.o with the following error in verifier:
infinite loop detected at insn 76
The byte code sequence looks like below, and noted that alu32 has been
turned off by default for better generated codes in general:
48: w3 = 100
49: *(u32 *)(r10 - 68) = r3
...
; if (tlv.type == SR6_TLV_PADDING) {
76: if w3 == 5 goto -18 <LBB0_19>
...
85: r1 = *(u32 *)(r10 - 68)
; for (int i = 0; i < 100; i++) {
86: w1 += -1
87: if w1 == 0 goto +5 <LBB0_20>
88: *(u32 *)(r10 - 68) = r1
The main reason for verification failure is due to partial spills at
r10 - 68 for induction variable "i".
Current verifier only handles spills with 8-byte values. The above 4-byte
value spill to stack is treated to STACK_MISC and its content is not
saved. For the above example:
w3 = 100
R3_w=inv100 fp-64_w=inv1086626730498
*(u32 *)(r10 - 68) = r3
R3_w=inv100 fp-64_w=inv1086626730498
...
r1 = *(u32 *)(r10 - 68)
R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff))
fp-64=inv1086626730498
To resolve this issue, verifier needs to be extended to track sub-registers
in spilling, or llvm needs to enhanced to prevent sub-register spilling
in register allocation phase. The former will increase verifier complexity
and the latter will need some llvm "hacking".
Let us workaround this issue by declaring the induction variable as "long"
type so spilling will happen at non sub-register level. We can revisit this
later if sub-register spilling causes similar or other verification issues.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191117214036.1309510-1-yhs@fb.com
