JP Kobryn says:
====================
allow kfuncs in tracepoint and perf event
It is possible to call a cpumask kfunc within a raw tp_btf program but not
possible within tracepoint or perf event programs. Currently, the verifier
receives -EACCESS from fetch_kfunc_meta() as a result of not finding any
kfunc hook associated with these program types.
This patch series associates tracepoint and perf event program types with
the tracing hook and includes test coverage.
Pre-submission CI run: https://github.com/kernel-patches/bpf/pull/7674
v3:
- map tracepoint and perf event progs to tracing kfunc hook
- expand existing verifier tests for kfuncs
- remove explicit registrations from v2
- no longer including kprobes
v2:
- create new kfunc hooks for tracepoint and perf event
- map tracepoint, and perf event prog types to kfunc hooks
- register cpumask kfuncs with prog types in focus
- expand existing verifier tests for cpumask kfuncs
v1:
- map tracepoint type progs to tracing kfunc hook
- new selftests for calling cpumask kfuncs in tracepoint prog
---
====================
Link: https://lore.kernel.org/r/20240905223812.141857-1-inwardvessel@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit 980ca8ceea ("bpf: check bpf_dummy_struct_ops program params for
test runs") does bitwise AND between reg_type and PTR_MAYBE_NULL, which
is correct, but due to type difference the compiler complains:
net/bpf/bpf_dummy_struct_ops.c:118:31: warning: bitwise operation between different enumeration types ('const enum bpf_reg_type' and 'enum bpf_type_flag') [-Wenum-enum-conversion]
118 | if (info && (info->reg_type & PTR_MAYBE_NULL))
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
Workaround the warning by moving the type_may_be_null() helper from
verifier.c into bpf_verifier.h, and reuse it here to check whether param
is nullable.
Fixes: 980ca8ceea ("bpf: check bpf_dummy_struct_ops program params for test runs")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404241956.HEiRYwWq-lkp@intel.com/
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240905055233.70203-1-shung-hsi.yu@suse.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds DENYLIST.riscv64 file for riscv64. It will help BPF CI
and local vmtest to mask failing and unsupported test cases.
We can use the following command to use deny list in local vmtest as
previously mentioned by Manu.
PLATFORM=riscv64 CROSS_COMPILE=riscv64-linux-gnu- vmtest.sh \
-l ./libbpf-vmtest-rootfs-2024.08.30-noble-riscv64.tar.zst -- \
./test_progs -d \
\"$(cat tools/testing/selftests/bpf/DENYLIST.riscv64 \
| cut -d'#' -f1 \
| sed -e 's/^[[:space:]]*//' \
-e 's/[[:space:]]*$//' \
| tr -s '\n' ','\
)\"
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/r/20240905081401.1894789-9-pulehui@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support cross platform testing for vmtest. The variable $ARCH in the
current script is platform semantics, not kernel semantics. Rename it to
$PLATFORM so that we can easily use $ARCH in cross-compilation. And drop
`set -u` unbound variable check as we will use CROSS_COMPILE env
variable. For now, Using PLATFORM= and CROSS_COMPILE= options will
enable cross platform testing:
PLATFORM=<platform> CROSS_COMPILE=<toolchain> vmtest.sh -- ./test_progs
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/r/20240905081401.1894789-7-pulehui@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Recently, when compiling bpf selftests on RV64, the following
compilation failure occurred:
progs/bpf_dctcp.c:29:21: error: redefinition of 'fallback' as different kind of symbol
29 | volatile const char fallback[TCP_CA_NAME_MAX];
| ^
/workspace/tools/testing/selftests/bpf/tools/include/vmlinux.h:86812:15: note: previous definition is here
86812 | typedef u32 (*fallback)(u32, const unsigned char *, size_t);
The reason is that the `fallback` symbol has been defined in
arch/riscv/lib/crc32.c, which will cause symbol conflicts when vmlinux.h
is included in bpf_dctcp. Let we rename `fallback` string to
`fallback_cc` in bpf_dctcp to fix this compilation failure.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/r/20240905081401.1894789-3-pulehui@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Hi, fix some spelling errors in libbpf, the details are as follows:
-in the code comments:
termintaing->terminating
architecutre->architecture
requring->requiring
recored->recoded
sanitise->sanities
allowd->allowed
abover->above
see bpf_udst_arg()->see bpf_usdt_arg()
Signed-off-by: Lin Yikai <yikai.lin@vivo.com>
Link: https://lore.kernel.org/r/20240905110354.3274546-3-yikai.lin@vivo.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Jiri Olsa says:
====================
selftests/bpf: Add uprobe multi pid filter test
hi,
sending fix for uprobe multi pid filtering together with tests. The first
version included tests for standard uprobes, but as we still do not have
fix for that, sending just uprobe multi changes.
thanks,
jirka
v2 changes:
- focused on uprobe multi only, removed perf event uprobe specific parts
- added fix and test for CLONE_VM process filter
---
====================
Link: https://lore.kernel.org/r/20240905115124.1503998-1-jolsa@kernel.org
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Uprobe multi link does its own process (thread leader) filtering before
running the bpf program by comparing task's vm pointers.
But as Oleg pointed out there can be processes sharing the vm (CLONE_VM),
so we can't just compare task->vm pointers, but instead we need to use
same_thread_group call.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/bpf/20240905115124.1503998-2-jolsa@kernel.org
The core part of the selftest, i.e., the je <-> jmp cycle, mimics the
original sched-ext bpf program. The test will fail without the
previous patch.
I tried to create some cases for other potential cycles
(je <-> je, jmp <-> je and jmp <-> jmp) with similar pattern
to the test in this patch, but failed. So this patch
only contains one test for je <-> jmp cycle.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240904221256.37389-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Hodges reported a jit error when playing with a sched-ext program.
The error message is:
unexpected jmp_cond padding: -4 bytes
But further investigation shows the error is actual due to failed
convergence. The following are some analysis:
...
pass4, final_proglen=4391:
...
20e: 48 85 ff test rdi,rdi
211: 74 7d je 0x290
213: 48 8b 77 00 mov rsi,QWORD PTR [rdi+0x0]
...
289: 48 85 ff test rdi,rdi
28c: 74 17 je 0x2a5
28e: e9 7f ff ff ff jmp 0x212
293: bf 03 00 00 00 mov edi,0x3
Note that insn at 0x211 is 2-byte cond jump insn for offset 0x7d (-125)
and insn at 0x28e is 5-byte jmp insn with offset -129.
pass5, final_proglen=4392:
...
20e: 48 85 ff test rdi,rdi
211: 0f 84 80 00 00 00 je 0x297
217: 48 8b 77 00 mov rsi,QWORD PTR [rdi+0x0]
...
28d: 48 85 ff test rdi,rdi
290: 74 1a je 0x2ac
292: eb 84 jmp 0x218
294: bf 03 00 00 00 mov edi,0x3
Note that insn at 0x211 is 6-byte cond jump insn now since its offset
becomes 0x80 based on previous round (0x293 - 0x213 = 0x80). At the same
time, insn at 0x292 is a 2-byte insn since its offset is -124.
pass6 will repeat the same code as in pass4. pass7 will repeat the same
code as in pass5, and so on. This will prevent eventual convergence.
Passes 1-14 are with padding = 0. At pass15, padding is 1 and related
insn looks like:
211: 0f 84 80 00 00 00 je 0x297
217: 48 8b 77 00 mov rsi,QWORD PTR [rdi+0x0]
...
24d: 48 85 d2 test rdx,rdx
The similar code in pass14:
211: 74 7d je 0x290
213: 48 8b 77 00 mov rsi,QWORD PTR [rdi+0x0]
...
249: 48 85 d2 test rdx,rdx
24c: 74 21 je 0x26f
24e: 48 01 f7 add rdi,rsi
...
Before generating the following insn,
250: 74 21 je 0x273
"padding = 1" enables some checking to ensure nops is either 0 or 4
where
#define INSN_SZ_DIFF (((addrs[i] - addrs[i - 1]) - (prog - temp)))
nops = INSN_SZ_DIFF - 2
In this specific case,
addrs[i] = 0x24e // from pass14
addrs[i-1] = 0x24d // from pass15
prog - temp = 3 // from 'test rdx,rdx' in pass15
so
nops = -4
and this triggers the failure.
To fix the issue, we need to break cycles of je <-> jmp. For example,
in the above case, we have
211: 74 7d je 0x290
the offset is 0x7d. If 2-byte je insn is generated only if
the offset is less than 0x7d (<= 0x7c), the cycle can be
break and we can achieve the convergence.
I did some study on other cases like je <-> je, jmp <-> je and
jmp <-> jmp which may cause cycles. Those cases are not from actual
reproducible cases since it is pretty hard to construct a test case
for them. the results show that the offset <= 0x7b (0x7b = 123) should
be enough to cover all cases. This patch added a new helper to generate 8-bit
cond/uncond jmp insns only if the offset range is [-128, 123].
Reported-by: Daniel Hodges <hodgesd@meta.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240904221251.37109-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch removes the insn_buf array stack usage from the
inline_bpf_loop(). Instead, the env->insn_buf is used. The
usage in inline_bpf_loop() needs more than 16 insn, so the
INSN_BUF_SIZE needs to be increased from 16 to 32.
The compiler stack size warning on the verifier is gone
after this change.
Cc: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240904180847.56947-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In commit ba8de796ba ("net: introduce sk_skb_reason_drop function")
kfree_skb_reason() becomes an inline function and cannot be traced.
samples/bpf is abandonware by now, and we should slowly but surely
convert whatever makes sense into BPF selftests under
tools/testing/selftests/bpf and just get rid of the rest.
Link: ba8de796ba
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Link: https://lore.kernel.org/r/tencent_30ADAC88CB2915CA57E9512D4460035BA107@qq.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When the PROCMAP_QUERY is not defined, a compilation error occurs due to the
mismatch of the procmap_query()'s params, procmap_query() only be called in
the file where the function is defined, modify the params so they can match.
We get a warning when build samples/bpf:
trace_helpers.c:252:5: warning: no previous prototype for ‘procmap_query’ [-Wmissing-prototypes]
252 | int procmap_query(int fd, const void *addr, __u32 query_flags, size_t *start, size_t *offset, int *flags)
| ^~~~~~~~~~~~~
As this function is only used in the file, mark it as 'static'.
Fixes: 4e9e07603e ("selftests/bpf: make use of PROCMAP_QUERY ioctl if available")
Signed-off-by: Yuan Chen <chenyuan@kylinos.cn>
Link: https://lore.kernel.org/r/20240903012839.3178-1-chenyuan_fl@163.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, BPF_CALL is always jited to indirect call. When target is
within the range of direct call, BPF_CALL can be jited to direct call.
For example, the following BPF_CALL
call __htab_map_lookup_elem
is always jited to indirect call:
mov x10, #0xffffffffffff18f4
movk x10, #0x821, lsl #16
movk x10, #0x8000, lsl #32
blr x10
When the address of target __htab_map_lookup_elem is within the range of
direct call, the BPF_CALL can be jited to:
bl 0xfffffffffd33bc98
This patch does such jit optimization by emitting arm64 direct calls for
BPF_CALL when possible, indirect calls otherwise.
Without this patch, the jit works as follows.
1. First pass
A. Determine jited position and size for each bpf instruction.
B. Computed the jited image size.
2. Allocate jited image with size computed in step 1.
3. Second pass
A. Adjust jump offset for jump instructions
B. Write the final image.
This works because, for a given bpf prog, regardless of where the jited
image is allocated, the jited result for each instruction is fixed. The
second pass differs from the first only in adjusting the jump offsets,
like changing "jmp imm1" to "jmp imm2", while the position and size of
the "jmp" instruction remain unchanged.
Now considering whether to jit BPF_CALL to arm64 direct or indirect call
instruction. The choice depends solely on the jump offset: direct call
if the jump offset is within 128MB, indirect call otherwise.
For a given BPF_CALL, the target address is known, so the jump offset is
decided by the jited address of the BPF_CALL instruction. In other words,
for a given bpf prog, the jited result for each BPF_CALL is determined
by its jited address.
The jited address for a BPF_CALL is the jited image address plus the
total jited size of all preceding instructions. For a given bpf prog,
there are clearly no BPF_CALL instructions before the first BPF_CALL
instruction. Since the jited result for all other instructions other
than BPF_CALL are fixed, the total jited size preceding the first
BPF_CALL is also fixed. Therefore, once the jited image is allocated,
the jited address for the first BPF_CALL is fixed.
Now that the jited result for the first BPF_CALL is fixed, the jited
results for all instructions preceding the second BPF_CALL are fixed.
So the jited address and result for the second BPF_CALL are also fixed.
Similarly, we can conclude that the jited addresses and results for all
subsequent BPF_CALL instructions are fixed.
This means that, for a given bpf prog, once the jited image is allocated,
the jited address and result for all instructions, including all BPF_CALL
instructions, are fixed.
Based on the observation, with this patch, the jit works as follows.
1. First pass
Estimate the maximum jited image size. In this pass, all BPF_CALLs
are jited to arm64 indirect calls since the jump offsets are unknown
because the jited image is not allocated.
2. Allocate jited image with size estimated in step 1.
3. Second pass
A. Determine the jited result for each BPF_CALL.
B. Determine jited address and size for each bpf instruction.
4. Third pass
A. Adjust jump offset for jump instructions.
B. Write the final image.
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Reviewed-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20240903094407.601107-1-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In bpftool-net documentation, two blank lines are missing in a
recently added example, causing docutils to complain:
$ cd tools/bpf/bpftool
$ make doc
DESCEND Documentation
GEN bpftool-btf.8
GEN bpftool-cgroup.8
GEN bpftool-feature.8
GEN bpftool-gen.8
GEN bpftool-iter.8
GEN bpftool-link.8
GEN bpftool-map.8
GEN bpftool-net.8
<stdin>:189: (INFO/1) Possible incomplete section title.
Treating the overline as ordinary text because it's so short.
<stdin>:192: (INFO/1) Blank line missing before literal block (after the "::")? Interpreted as a definition list item.
<stdin>:199: (INFO/1) Possible incomplete section title.
Treating the overline as ordinary text because it's so short.
<stdin>:201: (INFO/1) Blank line missing before literal block (after the "::")? Interpreted as a definition list item.
GEN bpftool-perf.8
GEN bpftool-prog.8
GEN bpftool.8
GEN bpftool-struct_ops.8
Add the missing blank lines.
Fixes: 0d7c06125c ("bpftool: Add document for net attach/detach on tcx subcommand")
Signed-off-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240901210742.25758-1-qmo@kernel.org
According to the documentation, when building a kernel with the C=2
parameter, all source files should be checked. But this does not happen
for the kernel/bpf/ directory.
$ touch kernel/bpf/core.o
$ make C=2 CHECK=true kernel/bpf/core.o
Outputs:
CHECK scripts/mod/empty.c
CALL scripts/checksyscalls.sh
DESCEND objtool
INSTALL libsubcmd_headers
CC kernel/bpf/core.o
As can be seen the compilation is done, but CHECK is not executed. This
happens because kernel/bpf/Makefile has defined its own rule for
compilation and forgotten the macro that does the check.
There is no need to duplicate the build code, and this rule can be
removed to use generic rules.
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lore.kernel.org/r/20240830074350.211308-1-legion@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds test cases for iter next method returning valid
pointer, which can also used as usage examples.
Currently iter next method should return valid pointer.
iter_next_trusted is the correct usage and test if iter next method
return valid pointer. bpf_iter_task_vma_next has KF_RET_NULL flag,
so the returned pointer may be NULL. We need to check if the pointer
is NULL before using it.
iter_next_trusted_or_null is the incorrect usage. There is no checking
before using the pointer, so it will be rejected by the verifier.
iter_next_rcu and iter_next_rcu_or_null are similar test cases for
KF_RCU_PROTECTED iterators.
iter_next_rcu_not_trusted is used to test that the pointer returned by
iter next method of KF_RCU_PROTECTED iterator cannot be passed in
KF_TRUSTED_ARGS kfuncs.
iter_next_ptr_mem_not_trusted is used to test that base type
PTR_TO_MEM should not be combined with type flag PTR_TRUSTED.
Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
Link: https://lore.kernel.org/r/AM6PR03MB5848709758F6922F02AF9F1F99962@AM6PR03MB5848.eurprd03.prod.outlook.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently we cannot pass the pointer returned by iter next method as
argument to KF_TRUSTED_ARGS or KF_RCU kfuncs, because the pointer
returned by iter next method is not "valid".
This patch sets the pointer returned by iter next method to be valid.
This is based on the fact that if the iterator is implemented correctly,
then the pointer returned from the iter next method should be valid.
This does not make NULL pointer valid. If the iter next method has
KF_RET_NULL flag, then the verifier will ask the ebpf program to
check NULL pointer.
KF_RCU_PROTECTED iterator is a special case, the pointer returned by
iter next method should only be valid within RCU critical section,
so it should be with MEM_RCU, not PTR_TRUSTED.
Another special case is bpf_iter_num_next, which returns a pointer with
base type PTR_TO_MEM. PTR_TO_MEM should not be combined with type flag
PTR_TRUSTED (PTR_TO_MEM already means the pointer is valid).
The pointer returned by iter next method of other types of iterators
is with PTR_TRUSTED.
In addition, this patch adds get_iter_from_state to help us get the
current iterator from the current state.
Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
Link: https://lore.kernel.org/r/AM6PR03MB584869F8B448EA1C87B7CDA399962@AM6PR03MB5848.eurprd03.prod.outlook.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Martin KaFai Lau says:
====================
bpf: Add gen_epilogue to bpf_verifier_ops
From: Martin KaFai Lau <martin.lau@kernel.org>
This set allows the subsystem to patch codes before BPF_EXIT.
The verifier ops, .gen_epilogue, is added for this purpose.
One of the use case will be in the bpf qdisc, the bpf qdisc
subsystem can ensure the skb->dev is in the correct value.
The bpf qdisc subsystem can either inline fixing it in the
epilogue or call another kernel function to handle it (e.g. drop)
in the epilogue. Another use case could be in bpf_tcp_ca.c to
enforce snd_cwnd has valid value (e.g. positive value).
v5:
* Removed the skip_cnt argument from adjust_jmp_off() in patch 2.
Instead, reuse the delta argument and skip
the [tgt_idx, tgt_idx + delta) instructions.
* Added a BPF_JMP32_A macro in patch 3.
* Removed pro_epilogue_subprog.c in patch 6.
The pro_epilogue_kfunc.c has covered the subprog case.
Renamed the file pro_epilogue_kfunc.c to pro_epilogue.c.
Some of the SEC names and function names are changed
accordingly (mainly shorten them by removing the _kfunc suffix).
* Added comments to explain the tail_call result in patch 7.
* Fixed the following bpf CI breakages. I ran it in CI
manually to confirm:
https://github.com/kernel-patches/bpf/actions/runs/10590714532
* s390 zext added "w3 = w3". Adjusted the test to
use all ALU64 and BPF_DW to avoid zext.
Also changed the "int a" in the "struct st_ops_args" to "u64 a".
* llvm17 does not take:
*(u64 *)(r1 +0) = 0;
so it is changed to:
r3 = 0;
*(u64 *)(r1 +0) = r3;
v4:
* Fixed a bug in the memcpy in patch 3
The size in the memcpy should be
epilogue_cnt * sizeof(*epilogue_buf)
v3:
* Moved epilogue_buf[16] to env.
Patch 1 is added to move the existing insn_buf[16] to env.
* Fixed a case that the bpf prog has a BPF_JMP that goes back
to the first instruction of the main prog.
The jump back to 1st insn case also applies to the prologue.
Patch 2 is added to handle it.
* If the bpf main prog has multiple BPF_EXIT, use a BPF_JA
to goto the earlier patched epilogue.
Note that there are (BPF_JMP32 | BPF_JA) vs (BPF_JMP | BPF_JA)
details in the patch 3 commit message.
* There are subtle changes in patch 3, so I reset the Reviewed-by.
* Added patch 8 and patch 9 to cover the changes in patch 2 and patch 3.
* Dropped the kfunc call from pro/epilogue and its selftests.
v2:
* Remove the RFC tag. Keep the ordering at where .gen_epilogue is
called in the verifier relative to the check_max_stack_depth().
This will be consistent with the other extra stack_depth
usage like optimize_bpf_loop().
* Use __xlated check provided by the test_loader to
check the patched instructions after gen_pro/epilogue (Eduard).
* Added Patch 3 by Eduard (Thanks!).
====================
Link: https://lore.kernel.org/r/20240829210833.388152-1-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
