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If PERF_EVENT program has __arg_ctx argument with matching
architecture-specific pt_regs/user_pt_regs/user_regs_struct pointer
type, libbpf should still perform type rewrite for old kernels, but not
emit the warning. Fix copy/paste from kernel code where 0 is meant to
signify "no error" condition. For libbpf we need to return "true" to
proceed with type rewrite (which for PERF_EVENT program will be
a canonical `struct bpf_perf_event_data *` type).
Fixes: 9eea8fafe33e ("libbpf: fix __arg_ctx type enforcement for perf_event programs")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240206002243.1439450-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Magnus Karlsson says:
====================
xsk: support redirect to any socket bound to the same umem
This patch set adds support for directing a packet to any socket bound
to the same umem. This makes it possible to use the XDP program to
select what socket the packet should be received on. The user can
populate the XSKMAP with various sockets and as long as they share the
same umem, the XDP program can pick any one of them.
The implementation is straight-forward. Instead of testing that the
incoming packet is targeting the same device and queue id as the
socket is bound to, just check that the umem the packet was received
on is the same as the socket we want it to be received on. This
guarantees that the redirect is legal as it is already in the correct
umem.
Patch #1 implements the feature and patch #2 adds documentation.
Thanks: Magnus
====================
Link: https://lore.kernel.org/r/20240205123553.22180-1-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support for directing a packet to any socket bound to the same
umem. This makes it possible to use the XDP program to select what
socket the packet should be received on. The user can populate the
XSKMAP with various sockets and as long as they share the same umem,
the XDP program can pick any one of them.
Suggested-by: Yuval El-Hanany <yuvale@radware.com>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240205123553.22180-2-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Kumar Kartikeya Dwivedi says:
====================
Transfer RCU lock state across subprog calls
David suggested during the discussion in [0] that we should handle RCU
locks in a similar fashion to spin locks where the verifier understands
when a lock held in a caller is released in callee, or lock taken in
callee is released in a caller, or the callee is called within a lock
critical section. This set extends the same semantics to RCU read locks
and adds a few selftests to verify correct behavior. This issue has also
come up for sched-ext programs.
This would now allow static subprog calls to be made without errors
within RCU read sections, for subprogs to release RCU locks of callers
and return to them, or for subprogs to take RCU lock which is later
released in the caller.
[0]: https://lore.kernel.org/bpf/20240204120206.796412-1-memxor@gmail.com
Changelog:
----------
v1 -> v2:
v1: https://lore.kernel.org/bpf/20240204230231.1013964-1-memxor@gmail.com
* Add tests for global subprog behaviour (Yafang)
* Add Acks, Tested-by (Yonghong, Yafang)
====================
Link: https://lore.kernel.org/r/20240205055646.1112186-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add selftests covering the following cases:
- A static or global subprog called from within a RCU read section works
- A static subprog taking an RCU read lock which is released in caller works
- A static subprog releasing the caller's RCU read lock works
Global subprogs that leave the lock in an imbalanced state will not
work, as they are verified separately, so ensure those cases fail as
well.
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20240205055646.1112186-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow transferring an imbalanced RCU lock state between subprog calls
during verification. This allows patterns where a subprog call returns
with an RCU lock held, or a subprog call releases an RCU lock held by
the caller. Currently, the verifier would end up complaining if the RCU
lock is not released when processing an exit from a subprog, which is
non-ideal if its execution is supposed to be enclosed in an RCU read
section of the caller.
Instead, simply only check whether we are processing exit for frame#0
and do not complain on an active RCU lock otherwise. We only need to
update the check when processing BPF_EXIT insn, as copy_verifier_state
is already set up to do the right thing.
Suggested-by: David Vernet <void@manifault.com>
Tested-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20240205055646.1112186-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Kumar Kartikeya Dwivedi says:
====================
Enable static subprog calls in spin lock critical sections
This set allows a BPF program to make a call to a static subprog within
a bpf_spin_lock critical section. This problem has been hit in sched-ext
and ghOSt [0] as well, and is mostly an annoyance which is worked around
by inling the static subprog into the critical section.
In case of sched-ext, there are a lot of other helper/kfunc calls that
need to be allow listed for the support to be complete, but a separate
follow up will deal with that.
Unlike static subprogs, global subprogs cannot be allowed yet as the
verifier will not explore their body when encountering a call
instruction for them. Therefore, we would need an alternative approach
(some sort of function summarization to ensure a lock is never taken
from a global subprog and all its callees).
[0]: https://lore.kernel.org/bpf/bd173bf2-dea6-3e0e-4176-4a9256a9a056@google.com
Changelog:
----------
v1 -> v2
v1: https://lore.kernel.org/bpf/20240204120206.796412-1-memxor@gmail.com
* Indicate global function call in verifier error string (Yonghong, David)
* Add Acks from Yonghong, David
====================
Link: https://lore.kernel.org/r/20240204222349.938118-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add selftests for static subprog calls within bpf_spin_lock critical
section, and ensure we still reject global subprog calls. Also test the
case where a subprog call will unlock the caller's held lock, or the
caller will unlock a lock taken by a subprog call, ensuring correct
transfer of lock state across frames on exit.
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240204222349.938118-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, calling any helpers, kfuncs, or subprogs except the graph
data structure (lists, rbtrees) API kfuncs while holding a bpf_spin_lock
is not allowed. One of the original motivations of this decision was to
force the BPF programmer's hand into keeping the bpf_spin_lock critical
section small, and to ensure the execution time of the program does not
increase due to lock waiting times. In addition to this, some of the
helpers and kfuncs may be unsafe to call while holding a bpf_spin_lock.
However, when it comes to subprog calls, atleast for static subprogs,
the verifier is able to explore their instructions during verification.
Therefore, it is similar in effect to having the same code inlined into
the critical section. Hence, not allowing static subprog calls in the
bpf_spin_lock critical section is mostly an annoyance that needs to be
worked around, without providing any tangible benefit.
Unlike static subprog calls, global subprog calls are not safe to permit
within the critical section, as the verifier does not explore them
during verification, therefore whether the same lock will be taken
again, or unlocked, cannot be ascertained.
Therefore, allow calling static subprogs within a bpf_spin_lock critical
section, and only reject it in case the subprog linkage is global.
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240204222349.938118-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch attempts to update the ISA specification according
to the latest mailing list discussion about conformance groups,
in a way that is intended to be consistent with IANA registry
processes and IETF 118 WG meeting discussion.
It does the following:
* Split basic into base32 and base64 for 32-bit vs 64-bit base
instructions
* Split division/multiplication/modulo instructions out of base groups
* Split atomic instructions out of base groups
There may be additional changes as discussion continues,
but there seems to be consensus on the principles above.
v1->v2: fixed typo pointed out by David Vernet
v2->v3: Moved multiplication to same groups as division/modulo
Signed-off-by: Dave Thaler <dthaler1968@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20240202221110.3872-1-dthaler1968@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Recently, when running './test_progs -j', I occasionally hit the
following errors:
test_lwt_redirect:PASS:pthread_create 0 nsec
test_lwt_redirect_run:FAIL:netns_create unexpected error: 256 (errno 0)
#142/2 lwt_redirect/lwt_redirect_normal_nomac:FAIL
#142 lwt_redirect:FAIL
test_lwt_reroute:PASS:pthread_create 0 nsec
test_lwt_reroute_run:FAIL:netns_create unexpected error: 256 (errno 0)
test_lwt_reroute:PASS:pthread_join 0 nsec
#143/2 lwt_reroute/lwt_reroute_qdisc_dropped:FAIL
#143 lwt_reroute:FAIL
The netns_create() definition looks like below:
#define NETNS "ns_lwt"
static inline int netns_create(void)
{
return system("ip netns add " NETNS);
}
One possibility is that both lwt_redirect and lwt_reroute create
netns with the same name "ns_lwt" which may cause conflict. I tried
the following example:
$ sudo ip netns add abc
$ echo $?
0
$ sudo ip netns add abc
Cannot create namespace file "/var/run/netns/abc": File exists
$ echo $?
1
$
The return code for above netns_create() is 256. The internet search
suggests that the return value for 'ip netns add ns_lwt' is 1, which
matches the above 'sudo ip netns add abc' example.
This patch tried to use different netns names for two tests to avoid
'ip netns add <name>' failure.
I ran './test_progs -j' 10 times and all succeeded with
lwt_redirect/lwt_reroute tests.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240205052914.1742687-1-yonghong.song@linux.dev
Somehow recently I frequently hit the following test failure
with either ./test_progs or ./test_progs-cpuv4:
serial_test_ptr_untrusted:PASS:skel_open 0 nsec
serial_test_ptr_untrusted:PASS:lsm_attach 0 nsec
serial_test_ptr_untrusted:PASS:raw_tp_attach 0 nsec
serial_test_ptr_untrusted:FAIL:cmp_tp_name unexpected cmp_tp_name: actual -115 != expected 0
#182 ptr_untrusted:FAIL
Further investigation found the failure is due to
bpf_probe_read_user_str()
where reading user-level string attr->raw_tracepoint.name
is not successfully, most likely due to the
string itself still in disk and not populated into memory yet.
One solution is do a printf() call of the string before doing bpf
syscall which will force the raw_tracepoint.name into memory.
But I think a more robust solution is to use bpf_copy_from_user()
which is used in sleepable program and can tolerate page fault,
and the fix here used the latter approach.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240204194452.2785936-1-yonghong.song@linux.dev
The "i" here is always equal to "btf_type_vlen(t)" since
the "for_each_member()" loop never breaks.
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240203055119.2235598-1-thinker.li@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Andrii Nakryiko says:
====================
Two small fixes for global subprog tagging
Fix a bug with passing trusted PTR_TO_BTF_ID_OR_NULL register into global
subprog that expects `__arg_trusted __arg_nullable` arguments, which was
discovered when adopting production BPF application.
Also fix annoying warnings that are irrelevant for static subprogs, which are
just an artifact of using btf_prepare_func_args() for both static and global
subprogs.
====================
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240202190529.2374377-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When btf_prepare_func_args() was generalized to handle both static and
global subprogs, a few warnings/errors that are meant only for global
subprog cases started to be emitted for static subprogs, where they are
sort of expected and irrelavant.
Stop polutting verifier logs with irrelevant scary-looking messages.
Fixes: e26080d0da87 ("bpf: prepare btf_prepare_func_args() for handling static subprogs")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240202190529.2374377-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add extra layer of global functions to ensure that passing around
(trusted) PTR_TO_BTF_ID_OR_NULL registers works as expected. We also
extend trusted_task_arg_nullable subtest to check three possible valid
argumements: known NULL, known non-NULL, and maybe NULL cases.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240202190529.2374377-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add PTR_TRUSTED | PTR_MAYBE_NULL modifiers for PTR_TO_BTF_ID to
check_reg_type() to support passing trusted nullable PTR_TO_BTF_ID
registers into global functions accepting `__arg_trusted __arg_nullable`
arguments. This hasn't been caught earlier because tests were either
passing known non-NULL PTR_TO_BTF_ID registers or known NULL (SCALAR)
registers.
When utilizing this functionality in complicated real-world BPF
application that passes around PTR_TO_BTF_ID_OR_NULL, it became apparent
that verifier rejects valid case because check_reg_type() doesn't handle
this case explicitly. Existing check_reg_type() logic is already
anticipating this combination, so we just need to explicitly list this
combo in the switch statement.
Fixes: e2b3c4ff5d18 ("bpf: add __arg_trusted global func arg tag")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240202190529.2374377-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
After commit c698eaebdf47 ("selftests/bpf: trace_helpers.c: Optimize
kallsyms cache") trace_helpers.c now includes libbpf_internal.h, and
thus can no longer use the u32 type (among others) since they are poison
in libbpf_internal.h. Replace u32 with __u32 to fix the following error
when building trace_helpers.c on powerpc:
error: attempt to use poisoned "u32"
Fixes: c698eaebdf47 ("selftests/bpf: trace_helpers.c: Optimize kallsyms cache")
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20240202095559.12900-1-shung-hsi.yu@suse.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Maxim Mikityanskiy says:
====================
Improvements for tracking scalars in the BPF verifier
From: Maxim Mikityanskiy <maxim@isovalent.com>
The goal of this series is to extend the verifier's capabilities of
tracking scalars when they are spilled to stack, especially when the
spill or fill is narrowing. It also contains a fix by Eduard for
infinite loop detection and a state pruning optimization by Eduard that
compensates for a verification complexity regression introduced by
tracking unbounded scalars. These improvements reduce the surface of
false rejections that I saw while working on Cilium codebase.
Patches 1-9 of the original series were previously applied in v2.
Patches 1-2 (Maxim): Support the case when boundary checks are first
performed after the register was spilled to the stack.
Patches 3-4 (Maxim): Support narrowing fills.
Patches 5-6 (Eduard): Optimization for state pruning in stacksafe() to
mitigate the verification complexity regression.
veristat -e file,prog,states -f '!states_diff<50' -f '!states_pct<10' -f '!states_a<10' -f '!states_b<10' -C ...
* Without patch 5:
File Program States (A) States (B) States (DIFF)
-------------------- -------- ---------- ---------- ----------------
pyperf100.bpf.o on_event 4878 6528 +1650 (+33.83%)
pyperf180.bpf.o on_event 6936 11032 +4096 (+59.05%)
pyperf600.bpf.o on_event 22271 39455 +17184 (+77.16%)
pyperf600_iter.bpf.o on_event 400 490 +90 (+22.50%)
strobemeta.bpf.o on_event 4895 14028 +9133 (+186.58%)
* With patch 5:
File Program States (A) States (B) States (DIFF)
----------------------- ------------- ---------- ---------- ---------------
bpf_xdp.o tail_lb_ipv4 2770 2224 -546 (-19.71%)
pyperf100.bpf.o on_event 4878 5848 +970 (+19.89%)
pyperf180.bpf.o on_event 6936 8868 +1932 (+27.85%)
pyperf600.bpf.o on_event 22271 29656 +7385 (+33.16%)
pyperf600_iter.bpf.o on_event 400 450 +50 (+12.50%)
xdp_synproxy_kern.bpf.o syncookie_tc 280 226 -54 (-19.29%)
xdp_synproxy_kern.bpf.o syncookie_xdp 302 228 -74 (-24.50%)
v2 changes:
Fixed comments in patch 1, moved endianness checks to header files in
patch 12 where possible, added Eduard's ACKs.
v3 changes:
Maxim: Removed __is_scalar_unbounded altogether, addressed Andrii's
comments.
Eduard: Patch #5 (#14 in v2) changed significantly:
- Logical changes:
- Handling of STACK_{MISC,ZERO} mix turned out to be incorrect:
a mix of MISC and ZERO in old state is not equivalent to e.g.
just MISC is current state, because verifier could have deduced
zero scalars from ZERO slots in old state for some loads.
- There is no reason to limit the change only to cases when
old or current stack is a spill of unbounded scalar,
it is valid to compare any 64-bit scalar spill with fake
register impersonating MISC.
- STACK_ZERO vs spilled zero case was dropped,
after recent changes for zero handling by Andrii and Yonghong
it is hard (impossible?) to conjure all ZERO slots for an spi.
=> the case does not make any difference in veristat results.
- Use global static variable for unbound_reg (Andrii)
- Code shuffling to remove duplication in stacksafe() (Andrii)
====================
Link: https://lore.kernel.org/r/20240127175237.526726-1-maxtram95@gmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Check that stacksafe() compares spilled scalars with STACK_MISC.
The following combinations are explored:
- old spill of imprecise scalar is equivalent to cur STACK_{MISC,INVALID}
(plus error in unpriv mode);
- old spill of precise scalar is not equivalent to cur STACK_MISC;
- old STACK_MISC is equivalent to cur scalar;
- old STACK_MISC is not equivalent to cur non-scalar.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240127175237.526726-7-maxtram95@gmail.com
When check_stack_read_fixed_off() reads value from an spi
all stack slots of which are set to STACK_{MISC,INVALID},
the destination register is set to unbound SCALAR_VALUE.
Exploit this fact by allowing stacksafe() to use a fake
unbound scalar register to compare 'mmmm mmmm' stack value
in old state vs spilled 64-bit scalar in current state
and vice versa.
Veristat results after this patch show some gains:
./veristat -C -e file,prog,states -f 'states_pct>10' not-opt after
File Program States (DIFF)
----------------------- --------------------- ---------------
bpf_overlay.o tail_rev_nodeport_lb4 -45 (-15.85%)
bpf_xdp.o tail_lb_ipv4 -541 (-19.57%)
pyperf100.bpf.o on_event -680 (-10.42%)
pyperf180.bpf.o on_event -2164 (-19.62%)
pyperf600.bpf.o on_event -9799 (-24.84%)
strobemeta.bpf.o on_event -9157 (-65.28%)
xdp_synproxy_kern.bpf.o syncookie_tc -54 (-19.29%)
xdp_synproxy_kern.bpf.o syncookie_xdp -74 (-24.50%)
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240127175237.526726-6-maxtram95@gmail.com
The previous commit allowed to preserve boundaries and track IDs of
scalars on narrowing fills. Add test cases for that pattern.
Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240127175237.526726-5-maxtram95@gmail.com
When the width of a fill is smaller than the width of the preceding
spill, the information about scalar boundaries can still be preserved,
as long as it's coerced to the right width (done by coerce_reg_to_size).
Even further, if the actual value fits into the fill width, the ID can
be preserved as well for further tracking of equal scalars.
Implement the above improvements, which makes narrowing fills behave the
same as narrowing spills and MOVs between registers.
Two tests are adjusted to accommodate for endianness differences and to
take into account that it's now allowed to do a narrowing fill from the
least significant bits.
reg_bounds_sync is added to coerce_reg_to_size to correctly adjust
umin/umax boundaries after the var_off truncation, for example, a 64-bit
value 0xXXXXXXXX00000000, when read as a 32-bit, gets umin = 0, umax =
0xFFFFFFFF, var_off = (0x0; 0xffffffff00000000), which needs to be
synced down to umax = 0, otherwise reg_bounds_sanity_check doesn't pass.
Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240127175237.526726-4-maxtram95@gmail.com
The previous commit added tracking for unbounded scalars on spill. Add
the test case to check the new functionality.
Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240127175237.526726-3-maxtram95@gmail.com
Support the pattern where an unbounded scalar is spilled to the stack,
then boundary checks are performed on the src register, after which the
stack frame slot is refilled into a register.
Before this commit, the verifier didn't treat the src register and the
stack slot as related if the src register was an unbounded scalar. The
register state wasn't copied, the id wasn't preserved, and the stack
slot was marked as STACK_MISC. Subsequent boundary checks on the src
register wouldn't result in updating the boundaries of the spilled
variable on the stack.
After this commit, the verifier will preserve the bond between src and
dst even if src is unbounded, which permits to do boundary checks on src
and refill dst later, still remembering its boundaries. Such a pattern
is sometimes generated by clang when compiling complex long functions.
One test is adjusted to reflect that now unbounded scalars are tracked.
Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240127175237.526726-2-maxtram95@gmail.com
Some benchmarks don't have either "consumer" or "producer" sides. For
example, trig-tp and other BPF triggering benchmarks don't have
consumers, as they only do "producing" by calling into syscall or
predefined uproes. As such it's valid for some benchmarks to have zero
consumers or producers. So allows to specify `-c0` explicitly.
This triggers another problem. If benchmark doesn't support either
consumer or producer side, consumer_thread/producer_thread callback will
be NULL, but benchmark runner will attempt to use those NULL callback to
create threads anyways. So instead of crashing with SIGSEGV in case of
misconfigured benchmark, detect the condition and report error.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240201172027.604869-6-andrii@kernel.org
Another API that was declared in libbpf.map but actual implementation
was missing. btf_ext__get_raw_data() was intended as a discouraged alias
to consistently-named btf_ext__raw_data(), so make this an actuality.
Fixes: 20eccf29e297 ("libbpf: hide and discourage inconsistently named getters")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240201172027.604869-5-andrii@kernel.org
Seems like original commit adding split BTF support intended to add
btf__new_split() API, and even declared it in libbpf.map, but never
added (trivial) implementation. Fix this.
Fixes: ba451366bf44 ("libbpf: Implement basic split BTF support")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240201172027.604869-4-andrii@kernel.org
LIBBPF_API annotation seems missing on libbpf_set_memlock_rlim API, so
add it to make this API callable from libbpf's shared library version.
Fixes: e542f2c4cd16 ("libbpf: Auto-bump RLIMIT_MEMLOCK if kernel needs it for BPF")
Fixes: ab9a5a05dc48 ("libbpf: fix up few libbpf.map problems")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240201172027.604869-3-andrii@kernel.org
There's already one main CONFIG_SECURITY_NETWORK ifdef block within
the sleepable_lsm_hooks BTF set. Consolidate this duplicated ifdef
block as there's no need for it and all things guarded by it should
remain in one place in this specific context.
Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/Zbt1smz43GDMbVU3@google.com
Enable inline bpf_kptr_xchg() test for RV64, and the test have passed as
show below:
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20240130124659.670321-3-pulehui@huaweicloud.com
RV64 JIT supports 64-bit BPF_XCHG atomic instructions. At the same time,
the underlying implementation of xchg() and atomic64_xchg() in RV64 both
are raw_xchg() that supported 64-bit. Therefore inline bpf_kptr_xchg()
will have equivalent semantics. Let's inline it for better performance.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20240130124659.670321-2-pulehui@huaweicloud.com
As discussed on the BPF IETF mailing list (see link), this patch updates
the "Legacy BPF Packet access instructions" section to clarify which
instructions are deprecated (vs which were never defined and so are not
deprecated).
Signed-off-by: Dave Thaler <dthaler1968@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: David Vernet <void@manifault.com>
Link: https://mailarchive.ietf.org/arch/msg/bpf/5LnnKm093cGpOmDI9TnLQLBXyys
Link: https://lore.kernel.org/bpf/20240131033759.3634-1-dthaler1968@gmail.com
After recent changes, Coverity complained about inconsistent null checks
in kernel_supports() function:
kernel_supports(const struct bpf_object *obj, ...)
[...]
// var_compare_op: Comparing obj to null implies that obj might be null
if (obj && obj->gen_loader)
return true;
// var_deref_op: Dereferencing null pointer obj
if (obj->token_fd)
return feat_supported(obj->feat_cache, feat_id);
[...]
- The original null check was introduced by commit [0], which introduced
a call `kernel_supports(NULL, ...)` in function bump_rlimit_memlock();
- This call was refactored to use `feat_supported(NULL, ...)` in commit [1].
Looking at all places where kernel_supports() is called:
- There is either `obj->...` access before the call;
- Or `obj` comes from `prog->obj` expression, where `prog` comes from
enumeration of programs in `obj`;
- Or `obj` comes from `prog->obj`, where `prog` is a parameter to one
of the API functions:
- bpf_program__attach_kprobe_opts;
- bpf_program__attach_kprobe;
- bpf_program__attach_ksyscall.
Assuming correct API usage, it appears that `obj` can never be null when
passed to kernel_supports(). Silence the Coverity warning by removing
redundant null check.
[0] e542f2c4cd16 ("libbpf: Auto-bump RLIMIT_MEMLOCK if kernel needs it for BPF")
[1] d6dd1d49367a ("libbpf: Further decouple feature checking logic from bpf_object")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240131212615.20112-1-eddyz87@gmail.com
Daniel Xu says:
====================
Annotate kfuncs in .BTF_ids section
=== Description ===
This is a bpf-treewide change that annotates all kfuncs as such inside
.BTF_ids. This annotation eventually allows us to automatically generate
kfunc prototypes from bpftool.
We store this metadata inside a yet-unused flags field inside struct
btf_id_set8 (thanks Kumar!). pahole will be taught where to look.
More details about the full chain of events are available in commit 3's
description.
The accompanying pahole and bpftool changes can be viewed
here on these "frozen" branches [0][1].
[0]: https://github.com/danobi/pahole/tree/kfunc_btf-v3-mailed
[1]: https://github.com/danobi/linux/tree/kfunc_bpftool-mailed
=== Changelog ===
Changes from v3:
* Rebase to bpf-next and add missing annotation on new kfunc
Changes from v2:
* Only WARN() for vmlinux kfuncs
Changes from v1:
* Move WARN_ON() up a call level
* Also return error when kfunc set is not properly tagged
* Use BTF_KFUNCS_START/END instead of flags
* Rename BTF_SET8_KFUNC to BTF_SET8_KFUNCS
====================
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/cover.1706491398.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit marks kfuncs as such inside the .BTF_ids section. The upshot
of these annotations is that we'll be able to automatically generate
kfunc prototypes for downstream users. The process is as follows:
1. In source, use BTF_KFUNCS_START/END macro pair to mark kfuncs
2. During build, pahole injects into BTF a "bpf_kfunc" BTF_DECL_TAG for
each function inside BTF_KFUNCS sets
3. At runtime, vmlinux or module BTF is made available in sysfs
4. At runtime, bpftool (or similar) can look at provided BTF and
generate appropriate prototypes for functions with "bpf_kfunc" tag
To ensure future kfunc are similarly tagged, we now also return error
inside kfunc registration for untagged kfuncs. For vmlinux kfuncs,
we also WARN(), as initcall machinery does not handle errors.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/e55150ceecbf0a5d961e608941165c0bee7bc943.1706491398.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This macro pair is functionally equivalent to BTF_SET8_START/END, except
with BTF_SET8_KFUNCS flag set in the btf_id_set8 flags field. The next
commit will codemod all kfunc set8s to this new variant such that all
kfuncs are tagged as such in .BTF_ids section.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/r/d536c57c7c2af428686853cc7396b7a44faa53b7.1706491398.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit adds support for flags on BTF_SET8s. struct btf_id_set8
already supported 32 bits worth of flags, but was only used for
alignment purposes before.
We now use these bits to encode flags. The first use case is tagging
kfunc sets with a flag so that pahole can recognize which
BTF_ID_FLAGS(func, ..) are actual kfuncs.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/r/7bb152ec76d6c2c930daec88e995bf18484a5ebb.1706491398.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
After a recent change in the vmtest runner, this test started failing
sporadically.
Investigation showed that this test was subject to race condition which
got exacerbated after the vm runner change. The symptoms being that the
logic that waited for an ICMPv4 packet is naive and will break if 5 or
more non-ICMPv4 packets make it to tap0.
When ICMPv6 is enabled, the kernel will generate traffic such as ICMPv6
router solicitation...
On a system with good performance, the expected ICMPv4 packet would very
likely make it to the network interface promptly, but on a system with
poor performance, those "guarantees" do not hold true anymore.
Given that the test is IPv4 only, this change disable IPv6 in the test
netns by setting `net.ipv6.conf.all.disable_ipv6` to 1.
This essentially leaves "ping" as the sole generator of traffic in the
network namespace.
If this test was to be made IPv6 compatible, the logic in
`wait_for_packet` would need to be modified.
In more details...
At a high level, the test does:
- create a new namespace
- in `setup_redirect_target` set up lo, tap0, and link_err interfaces as
well as add 2 routes that attaches ingress/egress sections of
`test_lwt_redirect.bpf.o` to the xmit path.
- in `send_and_capture_test_packets` send an ICMP packet and read off
the tap interface (using `wait_for_packet`) to check that a ICMP packet
with the right size is read.
`wait_for_packet` will try to read `max_retry` (5) times from the tap0
fd looking for an ICMPv4 packet matching some criteria.
The problem is that when we set up the `tap0` interface, because IPv6 is
enabled by default, traffic such as Router solicitation is sent through
tap0, as in:
# tcpdump -r /tmp/lwt_redirect.pc
reading from file /tmp/lwt_redirect.pcap, link-type EN10MB (Ethernet)
04:46:23.578352 IP6 :: > ff02::1:ffc0:4427: ICMP6, neighbor solicitation, who has fe80::fcba:dff:fec0:4427, length 32
04:46:23.659522 IP6 :: > ff02::16: HBH ICMP6, multicast listener report v2, 1 group record(s), length 28
04:46:24.389169 IP 10.0.0.1 > 20.0.0.9: ICMP echo request, id 122, seq 1, length 108
04:46:24.618599 IP6 fe80::fcba:dff:fec0:4427 > ff02::16: HBH ICMP6, multicast listener report v2, 1 group record(s), length 28
04:46:24.619985 IP6 fe80::fcba:dff:fec0:4427 > ff02::2: ICMP6, router solicitation, length 16
04:46:24.767326 IP6 fe80::fcba:dff:fec0:4427 > ff02::16: HBH ICMP6, multicast listener report v2, 1 group record(s), length 28
04:46:28.936402 IP6 fe80::fcba:dff:fec0:4427 > ff02::2: ICMP6, router solicitation, length 16
If `wait_for_packet` sees 5 non-ICMPv4 packets, it will return 0, which is what we see in:
2024-01-31T03:51:25.0336992Z test_lwt_redirect_run:PASS:netns_create 0 nsec
2024-01-31T03:51:25.0341309Z open_netns:PASS:malloc token 0 nsec
2024-01-31T03:51:25.0344844Z open_netns:PASS:open /proc/self/ns/net 0 nsec
2024-01-31T03:51:25.0350071Z open_netns:PASS:open netns fd 0 nsec
2024-01-31T03:51:25.0353516Z open_netns:PASS:setns 0 nsec
2024-01-31T03:51:25.0356560Z test_lwt_redirect_run:PASS:setns 0 nsec
2024-01-31T03:51:25.0360140Z open_tuntap:PASS:open(/dev/net/tun) 0 nsec
2024-01-31T03:51:25.0363822Z open_tuntap:PASS:ioctl(TUNSETIFF) 0 nsec
2024-01-31T03:51:25.0367402Z open_tuntap:PASS:fcntl(O_NONBLOCK) 0 nsec
2024-01-31T03:51:25.0371167Z setup_redirect_target:PASS:open_tuntap 0 nsec
2024-01-31T03:51:25.0375180Z setup_redirect_target:PASS:if_nametoindex 0 nsec
2024-01-31T03:51:25.0379929Z setup_redirect_target:PASS:ip link add link_err type dummy 0 nsec
2024-01-31T03:51:25.0384874Z setup_redirect_target:PASS:ip link set lo up 0 nsec
2024-01-31T03:51:25.0389678Z setup_redirect_target:PASS:ip addr add dev lo 10.0.0.1/32 0 nsec
2024-01-31T03:51:25.0394814Z setup_redirect_target:PASS:ip link set link_err up 0 nsec
2024-01-31T03:51:25.0399874Z setup_redirect_target:PASS:ip link set tap0 up 0 nsec
2024-01-31T03:51:25.0407731Z setup_redirect_target:PASS:ip route add 10.0.0.0/24 dev link_err encap bpf xmit obj test_lwt_redirect.bpf.o sec redir_ingress 0 nsec
2024-01-31T03:51:25.0419105Z setup_redirect_target:PASS:ip route add 20.0.0.0/24 dev link_err encap bpf xmit obj test_lwt_redirect.bpf.o sec redir_egress 0 nsec
2024-01-31T03:51:25.0427209Z test_lwt_redirect_normal:PASS:setup_redirect_target 0 nsec
2024-01-31T03:51:25.0431424Z ping_dev:PASS:if_nametoindex 0 nsec
2024-01-31T03:51:25.0437222Z send_and_capture_test_packets:FAIL:wait_for_epacket unexpected wait_for_epacket: actual 0 != expected 1
2024-01-31T03:51:25.0448298Z (/tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/lwt_redirect.c:175: errno: Success) test_lwt_redirect_normal egress test fails
2024-01-31T03:51:25.0457124Z close_netns:PASS:setns 0 nsec
When running in a VM which potential resource contrains, the odds that calling
`ping` is not scheduled very soon after bringing `tap0` up increases,
and with this the chances to get our ICMP packet pushed to position 6+
in the network trace.
To confirm this indeed solves the issue, I ran the test 100 times in a
row with:
errors=0
successes=0
for i in `seq 1 100`
do
./test_progs -t lwt_redirect/lwt_redirect_normal
if [ $? -eq 0 ]; then
successes=$((successes+1))
else
errors=$((errors+1))
fi
done
echo "successes: $successes/errors: $errors"
While this test would at least fail a couple of time every 10 runs, here
it ran 100 times with no error.
Fixes: 43a7c3ef8a15 ("selftests/bpf: Add lwt_xmit tests for BPF_REDIRECT")
Signed-off-by: Manu Bretelle <chantr4@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240131053212.2247527-1-chantr4@gmail.com
Andrii Nakryiko says:
====================
Add bpf_core_cast(<ptr>, <type>) macro wrapper around bpf_rdonly_cast() kfunc
to make it easier to use this functionality in BPF code. See patch #2 for
BPF selftests conversions demonstrating improvements in code succinctness.
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Use more ergonomic bpf_core_cast() macro instead of bpf_rdonly_cast() in
selftests code.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130212023.183765-3-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Add bpf_core_cast() macro that wraps bpf_rdonly_cast() kfunc. It's more
ergonomic than kfunc, as it automatically extracts btf_id with
bpf_core_type_id_kernel(), and works with type names. It also casts result
to (T *) pointer. See the definition of the macro, it's self-explanatory.
libbpf declares bpf_rdonly_cast() extern as __weak __ksym and should be
safe to not conflict with other possible declarations in user code.
But we do have a conflict with current BPF selftests that declare their
externs with first argument as `void *obj`, while libbpf opts into more
permissive `const void *obj`. This causes conflict, so we fix up BPF
selftests uses in the same patch.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130212023.183765-2-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Andrii Nakryiko says:
====================
Trusted PTR_TO_BTF_ID arg support in global subprogs
This patch set follows recent changes that added btf_decl_tag-based argument
annotation support for global subprogs. This time we add ability to pass
PTR_TO_BTF_ID (BTF-aware kernel pointers) arguments into global subprograms.
We support explicitly trusted arguments only, for now.
Patch #1 adds logic for arg:trusted tag support on the verifier side. Default
semantic of such arguments is non-NULL, enforced on caller side. But patch #2
adds arg:nullable tag that can be combined with arg:trusted to make callee
explicitly do the NULL check, which helps implement "optional" PTR_TO_BTF_ID
arguments.
Patch #3 adds libbpf-side __arg_trusted and __arg_nullable macros.
Patch #4 adds a bunch of tests validating __arg_trusted in combination with
__arg_nullable.
v2->v3:
- went back to arg:nullable and __arg_nullable naming;
- rebased on latest bpf-next after prepartory patches landed;
v1->v2:
- added fix up to type enforcement changes, landed earlier;
- dropped bpf_core_cast() changes, will post them separately, as they now
are not used in added tests;
- dropped arg:untrusted support (Alexei);
- renamed arg:nullable to arg:maybe_null (Alexei);
- and also added task_struct___local flavor tests (Alexei).
====================
Link: https://lore.kernel.org/r/20240130000648.2144827-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a bunch of test cases validating behavior of __arg_trusted and its
combination with __arg_nullable tag. We also validate CO-RE flavor
support by kernel for __arg_trusted args.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130000648.2144827-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add __arg_trusted to annotate global func args that accept trusted
PTR_TO_BTF_ID arguments.
Also add __arg_nullable to combine with __arg_trusted (and maybe other
tags in the future) to force global subprog itself (i.e., callee) to do
NULL checks, as opposed to default non-NULL semantics (and thus caller's
responsibility to ensure non-NULL values).
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130000648.2144827-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add ability to mark arg:trusted arguments with optional arg:nullable
tag to mark it as PTR_TO_BTF_ID_OR_NULL variant, which will allow
callers to pass NULL, and subsequently will force global subprog's code
to do NULL check. This allows to have "optional" PTR_TO_BTF_ID values
passed into global subprogs.
For now arg:nullable cannot be combined with anything else.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130000648.2144827-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support for passing PTR_TO_BTF_ID registers to global subprogs.
Currently only PTR_TRUSTED flavor of PTR_TO_BTF_ID is supported.
Non-NULL semantics is assumed, so caller will be forced to prove
PTR_TO_BTF_ID can't be NULL.
Note, we disallow global subprogs to destroy passed in PTR_TO_BTF_ID
arguments, even the trusted one. We achieve that by not setting
ref_obj_id when validating subprog code. This basically enforces (in
Rust terms) borrowing semantics vs move semantics. Borrowing semantics
seems to be a better fit for isolated global subprog validation
approach.
Implementation-wise, we utilize existing logic for matching
user-provided BTF type to kernel-side BTF type, used by BPF CO-RE logic
and following same matching rules. We enforce a unique match for types.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130000648.2144827-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
