One of the test assertions uses an uninitialized op_name, which leads
to some headscratching if it fails. Use a string constant instead.
Fixes: b1a7a480a1 ("selftests/bpf: Add fixed vs rotating verifier log tests")
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230413094740.18041-1-lmb@isovalent.com
Add tests for FOU and GUE encapsulation via the bpf_skb_{set,get}_fou_encap
kfuncs, using ipip devices in collect-metadata mode.
These tests make sure that we can successfully set and obtain FOU and GUE
encap parameters using ingress / egress BPF tc-hooks.
Signed-off-by: Christian Ehrig <cehrig@cloudflare.com>
Link: https://lore.kernel.org/r/040193566ddbdb0b53eb359f7ac7bbd316f338b5.1680874078.git.cehrig@cloudflare.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add verifier log tests for BPF_BTF_LOAD command, which are very similar,
conceptually, to BPF_PROG_LOAD tests. These are two separate commands
dealing with verbose verifier log, so should be both tested separately.
Test that log_buf==NULL condition *does not* return -ENOSPC.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-20-andrii@kernel.org
Add few extra test conditions to validate that it's ok to pass
log_buf==NULL and log_size==0 to BPF_PROG_LOAD command with the intent
to get log_true_size without providing a buffer.
Test that log_buf==NULL condition *does not* return -ENOSPC.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-19-andrii@kernel.org
Add additional test cases validating that log_true_size is consistent
between fixed and rotating log modes, and that log_true_size can be
used *exactly* without causing -ENOSPC, while using just 1 byte shorter
log buffer would cause -ENOSPC.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-18-andrii@kernel.org
Add selftests validating BPF_LOG_FIXED behavior, which used to be the
only behavior, and now default rotating BPF verifier log, which returns
just up to last N bytes of full verifier log, instead of returning
-ENOSPC.
To stress test correctness of in-kernel verifier log logic, we force it
to truncate program's verifier log to all lengths from 1 all the way to
its full size (about 450 bytes today). This was a useful stress test
while developing the feature.
For both fixed and rotating log modes we expect -ENOSPC if log contents
doesn't fit in user-supplied log buffer.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-7-andrii@kernel.org
Currently, if user-supplied log buffer to collect BPF verifier log turns
out to be too small to contain full log, bpf() syscall returns -ENOSPC,
fails BPF program verification/load, and preserves first N-1 bytes of
the verifier log (where N is the size of user-supplied buffer).
This is problematic in a bunch of common scenarios, especially when
working with real-world BPF programs that tend to be pretty complex as
far as verification goes and require big log buffers. Typically, it's
when debugging tricky cases at log level 2 (verbose). Also, when BPF program
is successfully validated, log level 2 is the only way to actually see
verifier state progression and all the important details.
Even with log level 1, it's possible to get -ENOSPC even if the final
verifier log fits in log buffer, if there is a code path that's deep
enough to fill up entire log, even if normally it would be reset later
on (there is a logic to chop off successfully validated portions of BPF
verifier log).
In short, it's not always possible to pre-size log buffer. Also, what's
worse, in practice, the end of the log most often is way more important
than the beginning, but verifier stops emitting log as soon as initial
log buffer is filled up.
This patch switches BPF verifier log behavior to effectively behave as
rotating log. That is, if user-supplied log buffer turns out to be too
short, verifier will keep overwriting previously written log,
effectively treating user's log buffer as a ring buffer. -ENOSPC is
still going to be returned at the end, to notify user that log contents
was truncated, but the important last N bytes of the log would be
returned, which might be all that user really needs. This consistent
-ENOSPC behavior, regardless of rotating or fixed log behavior, allows
to prevent backwards compatibility breakage. The only user-visible
change is which portion of verifier log user ends up seeing *if buffer
is too small*. Given contents of verifier log itself is not an ABI,
there is no breakage due to this behavior change. Specialized tools that
rely on specific contents of verifier log in -ENOSPC scenario are
expected to be easily adapted to accommodate old and new behaviors.
Importantly, though, to preserve good user experience and not require
every user-space application to adopt to this new behavior, before
exiting to user-space verifier will rotate log (in place) to make it
start at the very beginning of user buffer as a continuous
zero-terminated string. The contents will be a chopped off N-1 last
bytes of full verifier log, of course.
Given beginning of log is sometimes important as well, we add
BPF_LOG_FIXED (which equals 8) flag to force old behavior, which allows
tools like veristat to request first part of verifier log, if necessary.
BPF_LOG_FIXED flag is also a simple and straightforward way to check if
BPF verifier supports rotating behavior.
On the implementation side, conceptually, it's all simple. We maintain
64-bit logical start and end positions. If we need to truncate the log,
start position will be adjusted accordingly to lag end position by
N bytes. We then use those logical positions to calculate their matching
actual positions in user buffer and handle wrap around the end of the
buffer properly. Finally, right before returning from bpf_check(), we
rotate user log buffer contents in-place as necessary, to make log
contents contiguous. See comments in relevant functions for details.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-4-andrii@kernel.org
When trying to add a name to the hashmap, an error code of EEXIST is
returned and we continue as names are possibly duplicated in the sys
file.
If the last name in the file is a duplicate, we will continue to the
next iteration of the while loop, and exit the loop with a value of err
set to EEXIST and enter the error label with err set, which causes the
test to fail when it should not.
This change reset err to 0 before continue-ing into the next iteration,
this way, if there is no more data to read from the file we iterate
through, err will be set to 0.
Behaviour prior to this change:
```
test_kprobe_multi_bench_attach:FAIL:get_syms unexpected error: -17
(errno 2)
All error logs:
test_kprobe_multi_bench_attach:FAIL:get_syms unexpected error: -17
(errno 2)
Summary: 0/1 PASSED, 0 SKIPPED, 1 FAILED
```
After this change:
```
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
```
Signed-off-by: Manu Bretelle <chantr4@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230408022919.54601-1-chantr4@gmail.com
perf_event with type=PERF_TYPE_RAW and config=0x1b00 turned out to be not
reliable in ensuring LBR is active. Thus, test_progs:get_branch_snapshot is
not reliable in some systems. Replace it with PERF_COUNT_HW_CPU_CYCLES
event, which gives more consistent results.
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230407190130.2093736-1-song@kernel.org
Add various tests for code pattern '<non-const> NE/EQ <const>' implemented
in the previous verifier patch. Without the verifier patch, these new
tests will fail.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230406164500.1045715-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
xdp-features supported by veth driver are no more static, but they
depends on veth configuration (e.g. if GRO is enabled/disabled or
TX/RX queue configuration). Take it into account in xdp_redirect
xdp-features selftest for veth driver.
Fixes: fccca038f3 ("veth: take into account device reconfiguration for xdp_features flag")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/bc35455cfbb1d4f7f52536955ded81ad47d8dc54.1680777371.git.lorenzo@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
In some cases the loopback latency might be large enough, causing
the assertion on invocations to be run before ingress prog getting
executed. The assertion would fail and the test would flake.
This can be reliably reproduced by arbitrarily increasing the
loopback latency (thanks to [1]):
tc qdisc add dev lo root handle 1: htb default 12
tc class add dev lo parent 1:1 classid 1:12 htb rate 20kbps ceil 20kbps
tc qdisc add dev lo parent 1:12 netem delay 100ms
Fix this by waiting on the receive end, instead of instantly
returning to the assert. The call to read() will wait for the
default SO_RCVTIMEO timeout of 3 seconds provided by
start_server().
[1] https://gist.github.com/kstevens715/4598301
Reported-by: Martin KaFai Lau <martin.lau@linux.dev>
Link: https://lore.kernel.org/bpf/9c5c8b7e-1d89-a3af-5400-14fde81f4429@linux.dev/
Fixes: 3573f38401 ("selftests/bpf: Test CGROUP_STORAGE behavior on shared egress + ingress")
Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Link: https://lore.kernel.org/r/20230405193354.1956209-1-zhuyifei@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
In commit 22df776a9a ("tasks: Extract rcu_users out of union"), the
'refcount_t rcu_users' field was extracted out of a union with the
'struct rcu_head rcu' field. This allows us to safely perform a
refcount_inc_not_zero() on task->rcu_users when acquiring a reference on
a task struct. A prior patch leveraged this by making struct task_struct
an RCU-protected object in the verifier, and by bpf_task_acquire() to
use the task->rcu_users field for synchronization.
Now that we can use RCU to protect tasks, we no longer need
bpf_task_kptr_get(), or bpf_task_acquire_not_zero(). bpf_task_kptr_get()
is truly completely unnecessary, as we can just use RCU to get the
object. bpf_task_acquire_not_zero() is now equivalent to
bpf_task_acquire().
In addition to these changes, this patch also updates the associated
selftests to no longer use these kfuncs.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230331195733.699708-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
struct task_struct objects are a bit interesting in terms of how their
lifetime is protected by refcounts. task structs have two refcount
fields:
1. refcount_t usage: Protects the memory backing the task struct. When
this refcount drops to 0, the task is immediately freed, without
waiting for an RCU grace period to elapse. This is the field that
most callers in the kernel currently use to ensure that a task
remains valid while it's being referenced, and is what's currently
tracked with bpf_task_acquire() and bpf_task_release().
2. refcount_t rcu_users: A refcount field which, when it drops to 0,
schedules an RCU callback that drops a reference held on the 'usage'
field above (which is acquired when the task is first created). This
field therefore provides a form of RCU protection on the task by
ensuring that at least one 'usage' refcount will be held until an RCU
grace period has elapsed. The qualifier "a form of" is important
here, as a task can remain valid after task->rcu_users has dropped to
0 and the subsequent RCU gp has elapsed.
In terms of BPF, we want to use task->rcu_users to protect tasks that
function as referenced kptrs, and to allow tasks stored as referenced
kptrs in maps to be accessed with RCU protection.
Let's first determine whether we can safely use task->rcu_users to
protect tasks stored in maps. All of the bpf_task* kfuncs can only be
called from tracepoint, struct_ops, or BPF_PROG_TYPE_SCHED_CLS, program
types. For tracepoint and struct_ops programs, the struct task_struct
passed to a program handler will always be trusted, so it will always be
safe to call bpf_task_acquire() with any task passed to a program.
Note, however, that we must update bpf_task_acquire() to be KF_RET_NULL,
as it is possible that the task has exited by the time the program is
invoked, even if the pointer is still currently valid because the main
kernel holds a task->usage refcount. For BPF_PROG_TYPE_SCHED_CLS, tasks
should never be passed as an argument to the any program handlers, so it
should not be relevant.
The second question is whether it's safe to use RCU to access a task
that was acquired with bpf_task_acquire(), and stored in a map. Because
bpf_task_acquire() now uses task->rcu_users, it follows that if the task
is present in the map, that it must have had at least one
task->rcu_users refcount by the time the current RCU cs was started.
Therefore, it's safe to access that task until the end of the current
RCU cs.
With all that said, this patch makes struct task_struct is an
RCU-protected object. In doing so, we also change bpf_task_acquire() to
be KF_ACQUIRE | KF_RCU | KF_RET_NULL, and adjust any selftests as
necessary. A subsequent patch will remove bpf_task_kptr_get(), and
bpf_task_acquire_not_zero() respectively.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230331195733.699708-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Replacing extract_build_id with read_build_id that parses out
build id directly from elf without using readelf tool.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230331093157.1749137-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a test case testing the redirection from connectible AF_VSOCK
sockets to connectible AF_UNIX sockets.
Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Test verifier/xdp_direct_packet_access.c automatically converted to use inline assembly.
Original test would be removed in the next patch.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230328020813.392560-2-eddyz87@gmail.com
The current sk storage test ensures the memory free works when
the local_storage->smap is NULL.
This patch adds a task storage test to ensure the memory free
code path works when local_storage->smap is NULL.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230322215246.1675516-5-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Test verifier/direct_stack_access_wraparound.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-18-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
