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When LSE atomics are available, BPF atomic instructions are implemented
as single ARM64 atomic instructions, therefore it is easy to enable
these in bpf_arena using the currently available exception handling
setup.
LL_SC atomics use loops and therefore would need more work to enable in
bpf_arena.
Enable LSE atomics based instructions in bpf_arena and use the
bpf_jit_supports_insn() callback to reject atomics in bpf_arena if LSE
atomics are not available.
All atomics and arena_atomics selftests are passing:
[root@ip-172-31-2-216 bpf]# ./test_progs -a atomics,arena_atomics
#3/1 arena_atomics/add:OK
#3/2 arena_atomics/sub:OK
#3/3 arena_atomics/and:OK
#3/4 arena_atomics/or:OK
#3/5 arena_atomics/xor:OK
#3/6 arena_atomics/cmpxchg:OK
#3/7 arena_atomics/xchg:OK
#3 arena_atomics:OK
#10/1 atomics/add:OK
#10/2 atomics/sub:OK
#10/3 atomics/and:OK
#10/4 atomics/or:OK
#10/5 atomics/xor:OK
#10/6 atomics/cmpxchg:OK
#10/7 atomics/xchg:OK
#10 atomics:OK
Summary: 2/14 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20240426161116.441-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko says:
====================
Fix yet another case of mishandling SEC("struct_ops") programs that were
nulled out programmatically through BPF skeleton by the user.
While at it, add some improvements around detecting and reporting errors,
specifically a common case of declaring SEC("struct_ops") program, but
forgetting to actually make use of it by setting it as a callback
implementation in SEC(".struct_ops") variable (i.e., map) declaration.
A bunch of new selftests are added as well.
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Drive-by clean up, we shouldn't use meaningless "test_" prefix for
subtest names.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-8-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Add a simple test that validates that libbpf will reject isolated
struct_ops program early with helpful warning message.
Also validate that explicit use of such BPF program through BPF skeleton
after BPF object is open won't trigger any warnings.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-7-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Extend libbpf's pre-load checks for BPF programs, detecting more typical
conditions that are destinated to cause BPF program failure. This is an
opportunity to provide more helpful and actionable error message to
users, instead of potentially very confusing BPF verifier log and/or
error.
In this case, we detect struct_ops BPF program that was not referenced
anywhere, but still attempted to be loaded (according to libbpf logic).
Suggest that the program might need to be used in some struct_ops
variable. User will get a message of the following kind:
libbpf: prog 'test_1_forgotten': SEC("struct_ops") program isn't referenced anywhere, did you forget to use it?
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-6-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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strerror_r(), used from libbpf-specific libbpf_strerror_r() wrapper is
documented to return error in two different ways, depending on glibc
version. Take that into account when handling strerror_r()'s own errors,
which happens when we pass some non-standard (internal) kernel error to
it. Before this patch we'd have "ERROR: strerror_r(524)=22", which is
quite confusing. Now for the same situation we'll see a bit less
visually scary "unknown error (-524)".
At least we won't confuse user with irrelevant EINVAL (22).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-5-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Add a test which tests the case that was just fixed. Kernel has full
type information about callback, but user explicitly nulls out the
reference to declaratively set BPF program reference.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-4-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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There is yet another corner case where user can set STRUCT_OPS program
reference in STRUCT_OPS map to NULL, but libbpf will fail to disable
autoload for such BPF program. This time it's the case of "new" kernel
which has type information about callback field, but user explicitly
nulled-out program reference from user-space after opening BPF object.
Fix, hopefully, the last remaining unhandled case.
Fixes: 0737df6de946 ("libbpf: better fix for handling nulled-out struct_ops program")
Fixes: f973fccd43d3 ("libbpf: handle nulled-out program in struct_ops correctly")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-3-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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libbpf ensures that BPF program references set in map->st_ops->progs[i]
during open phase are always valid STRUCT_OPS programs. This is done in
bpf_object__collect_st_ops_relos(). So there is no need to double-check
that in bpf_map__init_kern_struct_ops().
Simplify the code by removing unnecessary check. Also, we avoid using
local prog variable to keep code similar to the upcoming fix, which adds
similar logic in another part of bpf_map__init_kern_struct_ops().
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-2-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Cupertino Miranda says:
====================
Fix number of arguments in test
Hi everyone,
This is a new version based on comments.
Regards,
Cupertino
Changes from v1:
- Comment with gcc-bpf replaced by bpf_gcc.
- Used pragma GCC optimize to disable GCC optimization in test.
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
====================
Link: https://lore.kernel.org/r/20240507122220.207820-1-cupertino.miranda@oracle.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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The test_xdp_noinline.c contains 2 functions that use more then 5
arguments. This patch collapses the 2 last arguments in an array.
Also in GCC and ipa_sra optimization increases the number of arguments
used in function encap_v4. This pass disables the optimization for that
particular file.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240507122220.207820-3-cupertino.miranda@oracle.com
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This patch adds support to specify CFLAGS per source file and per test
runner.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240507122220.207820-2-cupertino.miranda@oracle.com
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The vmlinux.h file generated by bpftool makes use of compiler pragmas
in order to install the CO-RE preserve_access_index in all the struct
types derived from the BTF info:
#ifndef __VMLINUX_H__
#define __VMLINUX_H__
#ifndef BPF_NO_PRESERVE_ACCESS_INDEX
#pragma clang attribute push (__attribute__((preserve_access_index)), apply_t = record
#endif
[... type definitions generated from kernel BTF ... ]
#ifndef BPF_NO_PRESERVE_ACCESS_INDEX
#pragma clang attribute pop
#endif
The `clang attribute push/pop' pragmas are specific to clang/llvm and
are not supported by GCC.
At the moment the BTF dumping services in libbpf do not support
dicriminating between types dumped because they are directly referred
and types dumped because they are dependencies. A suitable API is
being worked now. See [1] and [2].
In the interim, this patch changes the selftests/bpf Makefile so it
passes -DBPF_NO_PRESERVE_ACCESS_INDEX to GCC when it builds the
selftests. This workaround is temporary, and may have an impact on
the results of the GCC-built tests.
[1] https://lore.kernel.org/bpf/20240503111836.25275-1-jose.marchesi@oracle.com/T/#u
[2] https://lore.kernel.org/bpf/20240504205510.24785-1-jose.marchesi@oracle.com/T/#u
Tested in bpf-next master.
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240507095011.15867-1-jose.marchesi@oracle.com
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Jose E. Marchesi says:
====================
bpf: avoid `attribute ignored' warnings in GCC
These two patches avoid warnings (turned into errors) when building
the BPF selftests with GCC.
[Changes from V1:
- As requested by reviewer, an additional patch has been added in
order to remove __hidden from the `private' macro in
cpumask_common.h.
- Typo bening -> benign fixed in the commit message of the second
patch.]
====================
Link: https://lore.kernel.org/r/20240507074227.4523-1-jose.marchesi@oracle.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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This patch modifies selftests/bpf/Makefile to pass -Wno-attributes to
GCC. This is because of the following attributes which are ignored:
- btf_decl_tag
- btf_type_tag
There are many of these. At the moment none of these are
recognized/handled by gcc-bpf.
We are aware that btf_decl_tag is necessary for some of the
selftest harness to communicate test failure/success. Support for
it is in progress in GCC upstream:
https://gcc.gnu.org/pipermail/gcc-patches/2024-May/650482.html
However, the GCC master branch is not yet open, so the series
above (currently under review upstream) wont be able to make it
there until 14.1 gets released, probably mid next week.
As for btf_type_tag, more extensive work will be needed in GCC
upstream to support it in both BTF and DWARF. We have a WIP big
patch for that, but that is not needed to compile/build the
selftests.
- used
There are SEC macros defined in the selftests as:
#define SEC(N) __attribute__((section(N),used))
The SEC macro is used for both functions and global variables.
According to the GCC documentation `used' attribute is really only
meaningful for functions, and it warns when the attribute is used
for other global objects, like for example ctl_array in
test_xdp_noinline.c.
Ignoring this is benign.
- align_value
In progs/test_cls_redirect.c:127 there is:
typedef uint8_t *net_ptr __attribute__((align_value(8)));
GCC warns that it is ignoring this attribute, because it is not
implemented by GCC.
I think ignoring this attribute in GCC is benign, because according
to the clang documentation [1] its purpose seems to be merely
declarative and doesn't seem to translate into extra checks at
run-time, only to perhaps better optimized code ("runtime behavior
is undefined if the pointed memory object is not aligned to the
specified alignment").
[1] https://clang.llvm.org/docs/AttributeReference.html#align-value
Tested in bpf-next master.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240507074227.4523-3-jose.marchesi@oracle.com
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An object defined as `static' defaults to hidden visibility. If
additionally the visibility(__weak__) compiler attribute is applied to
the declaration of the object, GCC warns that the attribute gets
ignored.
This patch removes the only instance of this problem among the BPF
selftests.
Tested in bpf-next master.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240507074227.4523-2-jose.marchesi@oracle.com
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As the comment described in "struct vm_fault":
".address" : 'Faulting virtual address - masked'
".real_address" : 'Faulting virtual address - unmasked'
The link [1] said: "Whatever the routes, all architectures end up to the
invocation of handle_mm_fault() which, in turn, (likely) ends up calling
__handle_mm_fault() to carry out the actual work of allocating the page
tables."
__handle_mm_fault() does address assignment:
.address = address & PAGE_MASK,
.real_address = address,
This is debug dump by running `./test_progs -a "*arena*"`:
[ 69.767494] arena fault: vmf->address = 10000001d000, vmf->real_address = 10000001d008
[ 69.767496] arena fault: vmf->address = 10000001c000, vmf->real_address = 10000001c008
[ 69.767499] arena fault: vmf->address = 10000001b000, vmf->real_address = 10000001b008
[ 69.767501] arena fault: vmf->address = 10000001a000, vmf->real_address = 10000001a008
[ 69.767504] arena fault: vmf->address = 100000019000, vmf->real_address = 100000019008
[ 69.769388] arena fault: vmf->address = 10000001e000, vmf->real_address = 10000001e1e8
So we can use the value of 'vmf->address' to do BPF arena kernel address
space cast directly.
[1] https://docs.kernel.org/mm/page_tables.html
Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Link: https://lore.kernel.org/r/20240507063358.8048-1-haiyue.wang@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Cupertino Miranda says:
====================
bpf/verifier: range computation improvements
Hi everyone,
This is what I hope to be the last version. :)
Regards,
Cupertino
Changes from v1:
- Reordered patches in the series.
- Fix refactor to be acurate with original code.
- Fixed other mentioned small problems.
Changes from v2:
- Added a patch to replace mark_reg_unknowon for __mark_reg_unknown in
the context of range computation.
- Reverted implementation of refactor to v1 which used a simpler
boolean return value in check function.
- Further relaxed MUL to allow it to still compute a range when neither
of its registers is a known value.
- Simplified tests based on Eduards example.
- Added messages in selftest commits.
Changes from v3:
- Improved commit message of patch nr 1.
- Coding style fixes.
- Improve XOR and OR tests.
- Made function calls to pass struct bpf_reg_state pointer instead.
- Improved final code as a last patch.
Changes from v4:
- Merged patch nr 7 in 2.
====================
Link: https://lore.kernel.org/r/20240506141849.185293-1-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Added a test for bound computation in MUL when non constant
values are used and both registers have bounded ranges.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Link: https://lore.kernel.org/r/20240506141849.185293-7-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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MUL instruction required that src_reg would be a known value (i.e.
src_reg would be a const value). The condition in this case can be
relaxed, since the range computation algorithm used in current code
already supports a proper range computation for any valid range value on
its operands.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Link: https://lore.kernel.org/r/20240506141849.185293-6-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Added a test for bound computation in XOR and OR when non constant
values are used and both registers have bounded ranges.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Link: https://lore.kernel.org/r/20240506141849.185293-5-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Range for XOR and OR operators would not be attempted unless src_reg
would resolve to a single value, i.e. a known constant value.
This condition is unnecessary, and the following XOR/OR operator
handling could compute a possible better range.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Link: https://lore.kernel.org/r/20240506141849.185293-4-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Split range computation checks in its own function, isolating pessimitic
range set for dst_reg and failing return to a single point.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
bpf/verifier: improve code after range computation recent changes.
Link: https://lore.kernel.org/r/20240506141849.185293-3-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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In order to further simplify the code in adjust_scalar_min_max_vals all
the calls to mark_reg_unknown are replaced by __mark_reg_unknown.
static void mark_reg_unknown(struct bpf_verifier_env *env,
struct bpf_reg_state *regs, u32 regno)
{
if (WARN_ON(regno >= MAX_BPF_REG)) {
... mark all regs not init ...
return;
}
__mark_reg_unknown(env, regs + regno);
}
The 'regno >= MAX_BPF_REG' does not apply to
adjust_scalar_min_max_vals(), because it is only called from the
following stack:
- check_alu_op
- adjust_reg_min_max_vals
- adjust_scalar_min_max_vals
The check_alu_op() does check_reg_arg() which verifies that both src and
dst register numbers are within bounds.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Link: https://lore.kernel.org/r/20240506141849.185293-2-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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When building either tools/bpf/bpftool, or tools/testing/selftests/hid,
(the same Makefile is used for these), clang generates many instances of
the following:
"clang: warning: -lLLVM-17: 'linker' input unused"
Quentin points out that the LLVM version is only required in $(LIBS),
not in $(CFLAGS), so the fix is to remove it from CFLAGS.
Suggested-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/bpf/20240505230054.13813-1-jhubbard@nvidia.com
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Cast operation has a higher precedence than addition. The code here
wants to zero the 2nd half of the 64-bit metadata, but due to a pointer
arithmetic mistake, it writes the zero at offset 16 instead.
Just adding parentheses around "data + 4" would fix this, but I think
this will be slightly better readable with array syntax.
I was unable to test this with tools/testing/selftests/bpf/vmtest.sh,
because my glibc is newer than glibc in the provided VM image.
So I just checked the difference in the compiled code.
objdump -S tools/testing/selftests/bpf/xdp_do_redirect.test.o:
- *((__u32 *)data) = 0x42; /* metadata test value */
+ ((__u32 *)data)[0] = 0x42; /* metadata test value */
be7: 48 8d 85 30 fc ff ff lea -0x3d0(%rbp),%rax
bee: c7 00 42 00 00 00 movl $0x42,(%rax)
- *((__u32 *)data + 4) = 0;
+ ((__u32 *)data)[1] = 0;
bf4: 48 8d 85 30 fc ff ff lea -0x3d0(%rbp),%rax
- bfb: 48 83 c0 10 add $0x10,%rax
+ bfb: 48 83 c0 04 add $0x4,%rax
bff: c7 00 00 00 00 00 movl $0x0,(%rax)
Fixes: 5640b6d89434 ("selftests/bpf: fix "metadata marker" getting overwritten by the netstack")
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20240506145023.214248-1-mschmidt@redhat.com
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The bpf programs that this patch changes require the BPF_PROG macro.
The BPF_PROG macro is defined in the libbpf's bpf_tracing.h.
Some tests include bpf_tcp_helpers.h which includes bpf_tracing.h.
They don't need other things from bpf_tcp_helpers.h other than
bpf_tracing.h. This patch simplifies it by directly including
the bpf_tracing.h.
The motivation of this unnecessary code churn is to retire
the bpf_tcp_helpers.h by directly using vmlinux.h. Right now,
the main usage of the bpf_tcp_helpers.h is the partial kernel
socket definitions (e.g. socket, sock, tcp_sock). While the test
cases continue to grow, fields are kept adding to those partial
socket definitions (e.g. the recent bpf_cc_cubic.c test which
tried to extend bpf_tcp_helpers.c but eventually used the
vmlinux.h instead).
The idea is to retire bpf_tcp_helpers.c and consistently use
vmlinux.h for the tests that require the kernel sockets. This
patch tackles the obvious tests that can directly use bpf_tracing.h
instead of bpf_tcp_helpers.h.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240504005045.848376-1-martin.lau@linux.dev
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[Differences from V1:
- Do not introduce a global typedef, as this is a public header.
- Keep the void* casts in BPF_KPROBE_READ_RET_IP and
BPF_KRETPROBE_READ_RET_IP, as these are necessary
for converting to a const void* argument of
bpf_probe_read_kernel.]
The BPF_PROG, BPF_KPROBE and BPF_KSYSCALL macros defined in
tools/lib/bpf/bpf_tracing.h use a clever hack in order to provide a
convenient way to define entry points for BPF programs as if they were
normal C functions that get typed actual arguments, instead of as
elements in a single "context" array argument.
For example, PPF_PROGS allows writing:
SEC("struct_ops/cwnd_event")
void BPF_PROG(cwnd_event, struct sock *sk, enum tcp_ca_event event)
{
bbr_cwnd_event(sk, event);
dctcp_cwnd_event(sk, event);
cubictcp_cwnd_event(sk, event);
}
That expands into a pair of functions:
void ____cwnd_event (unsigned long long *ctx, struct sock *sk, enum tcp_ca_event event)
{
bbr_cwnd_event(sk, event);
dctcp_cwnd_event(sk, event);
cubictcp_cwnd_event(sk, event);
}
void cwnd_event (unsigned long long *ctx)
{
_Pragma("GCC diagnostic push")
_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")
return ____cwnd_event(ctx, (void*)ctx[0], (void*)ctx[1]);
_Pragma("GCC diagnostic pop")
}
Note how the 64-bit unsigned integers in the incoming CTX get casted
to a void pointer, and then implicitly converted to whatever type of
the actual argument in the wrapped function. In this case:
Arg1: unsigned long long -> void * -> struct sock *
Arg2: unsigned long long -> void * -> enum tcp_ca_event
The behavior of GCC and clang when facing such conversions differ:
pointer -> pointer
Allowed by the C standard.
GCC: no warning nor error.
clang: no warning nor error.
pointer -> integer type
[C standard says the result of this conversion is implementation
defined, and it may lead to unaligned pointer etc.]
GCC: error: integer from pointer without a cast [-Wint-conversion]
clang: error: incompatible pointer to integer conversion [-Wint-conversion]
pointer -> enumerated type
GCC: error: incompatible types in assigment (*)
clang: error: incompatible pointer to integer conversion [-Wint-conversion]
These macros work because converting pointers to pointers is allowed,
and converting pointers to integers also works provided a suitable
integer type even if it is implementation defined, much like casting a
pointer to uintptr_t is guaranteed to work by the C standard. The
conversion errors emitted by both compilers by default are silenced by
the pragmas.
However, the GCC error marked with (*) above when assigning a pointer
to an enumerated value is not associated with the -Wint-conversion
warning, and it is not possible to turn it off.
This is preventing building the BPF kernel selftests with GCC.
This patch fixes this by avoiding intermediate casts to void*,
replaced with casts to `unsigned long long', which is an integer type
capable of safely store a BPF pointer, much like the standard
uintptr_t.
Testing performed in bpf-next master:
- vmtest.sh -- ./test_verifier
- vmtest.sh -- ./test_progs
- make M=samples/bpf
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240502170925.3194-1-jose.marchesi@oracle.com
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The macro bpf_ksym_exists is defined in bpf_helpers.h as:
#define bpf_ksym_exists(sym) ({ \
_Static_assert(!__builtin_constant_p(!!sym), #sym " should be marked as __weak"); \
!!sym; \
})
The purpose of the macro is to determine whether a given symbol has
been defined, given the address of the object associated with the
symbol. It also has a compile-time check to make sure the object
whose address is passed to the macro has been declared as weak, which
makes the check on `sym' meaningful.
As it happens, the check for weak doesn't work in GCC in all cases,
because __builtin_constant_p not always folds at parse time when
optimizing. This is because optimizations that happen later in the
compilation process, like inlining, may make a previously non-constant
expression a constant. This results in errors like the following when
building the selftests with GCC:
bpf_helpers.h:190:24: error: expression in static assertion is not constant
190 | _Static_assert(!__builtin_constant_p(!!sym), #sym " should be marked as __weak"); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fortunately recent versions of GCC support a __builtin_has_attribute
that can be used to directly check for the __weak__ attribute. This
patch changes bpf_helpers.h to use that builtin when building with a
recent enough GCC, and to omit the check if GCC is too old to support
the builtin.
The macro used for GCC becomes:
#define bpf_ksym_exists(sym) ({ \
_Static_assert(__builtin_has_attribute (*sym, __weak__), #sym " should be marked as __weak"); \
!!sym; \
})
Note that since bpf_ksym_exists is designed to get the address of the
object associated with symbol SYM, we pass *sym to
__builtin_has_attribute instead of sym. When an expression is passed
to __builtin_has_attribute then it is the type of the passed
expression that is checked for the specified attribute. The
expression itself is not evaluated. This accommodates well with the
existing usages of the macro:
- For function objects:
struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym __weak;
[...]
bpf_ksym_exists(bpf_task_acquire)
- For variable objects:
extern const struct rq runqueues __ksym __weak; /* typed */
[...]
bpf_ksym_exists(&runqueues)
Note also that BPF support was added in GCC 10 and support for
__builtin_has_attribute in GCC 9.
Locally tested in bpf-next master branch.
No regressions.
Signed-of-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240428112559.10518-1-jose.marchesi@oracle.com
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Add INT_MAX check to ring_buffer__consume_n(). We do the similar check
to handle int return result of all these ring buffer APIs in other APIs
and ring_buffer__consume_n() is missing one. This patch fixes this
omission.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240430201952.888293-2-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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ringbuf_process_ring() return int64_t, while ring__consume_n() assigns
it to int. It's highly unlikely, but possible for ringbuf_process_ring()
to return value larger than INT_MAX, so use int64_t. ring__consume_n()
does check INT_MAX before returning int result to the user.
Fixes: 4d22ea94ea33 ("libbpf: Add ring__consume_n / ring_buffer__consume_n")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240430201952.888293-1-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Miao Xu says:
====================
This patchset attempts to add two new arguments into the hookpoint
cong_control in tcp_congestion_ops. The new arguments are inherited
from the caller tcp_cong_control and can be used by any bpf cc prog
that implements its own logic inside this hookpoint.
Please review. Thanks a lot!
Changelog
=====
v2->v3:
- Fixed the broken selftest caused by the new arguments.
- Renamed the selftest file name and bpf prog name.
v1->v2:
- Split the patchset into 3 separate patches.
- Added highlights in the selftest prog.
- Removed the dependency on bpf_tcp_helpers.h.
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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This patch adds a selftest to show the usage of the new arguments in
cong_control. For simplicity's sake, the testing example reuses cubic's
kernel functions.
Signed-off-by: Miao Xu <miaxu@meta.com>
Link: https://lore.kernel.org/r/20240502042318.801932-4-miaxu@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
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This patch allows the write of tp->snd_cwnd_stamp in a bpf tcp
ca program. An use case of writing this field is to keep track
of the time whenever tp->snd_cwnd is raised or reduced inside
the `cong_control` callback.
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Miao Xu <miaxu@meta.com>
Link: https://lore.kernel.org/r/20240502042318.801932-3-miaxu@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
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This patch adds two new arguments for cong_control of struct
tcp_congestion_ops:
- ack
- flag
These two arguments are inherited from the caller tcp_cong_control in
tcp_intput.c. One use case of them is to update cwnd and pacing rate
inside cong_control based on the info they provide. For example, the
flag can be used to decide if it is the right time to raise or reduce a
sender's cwnd.
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Miao Xu <miaxu@meta.com>
Link: https://lore.kernel.org/r/20240502042318.801932-2-miaxu@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Jordan Rife says:
====================
This patch series adds test coverage for BPF sockaddr hooks and their
interactions with kernel socket functions (i.e. kernel_bind(),
kernel_connect(), kernel_sendmsg(), sock_sendmsg(),
kernel_getpeername(), and kernel_getsockname()) while also rounding out
IPv4 and IPv6 sockaddr hook coverage in prog_tests/sock_addr.c.
As with v1 of this patch series, we add regression coverage for the
issues addressed by these patches,
- commit 0bdf399342c5("net: Avoid address overwrite in kernel_connect")
- commit 86a7e0b69bd5("net: prevent rewrite of msg_name in sock_sendmsg()")
- commit c889a99a21bf("net: prevent address rewrite in kernel_bind()")
- commit 01b2885d9415("net: Save and restore msg_namelen in sock_sendmsg")
but broaden the focus a bit.
In order to extend prog_tests/sock_addr.c to test these kernel
functions, we add a set of new kfuncs that wrap individual socket
operations to bpf_testmod and invoke them through set of corresponding
SYSCALL programs (progs/sock_addr_kern.c). Each test case can be
configured to use a different set of "sock_ops" depending on whether it
is testing kernel calls (kernel_bind(), kernel_connect(), etc.) or
system calls (bind(), connect(), etc.).
=======
Patches
=======
* Patch 1 fixes the sock_addr bind test program to work for big endian
architectures such as s390x.
* Patch 2 introduces the new kfuncs to bpf_testmod.
* Patch 3 introduces the BPF program which allows us to invoke these
kfuncs invividually from the test program.
* Patch 4 lays the groundwork for IPv4 and IPv6 sockaddr hook coverage
by migrating much of the environment setup logic from
bpf/test_sock_addr.sh into prog_tests/sock_addr.c and moves test cases
to cover bind4/6, connect4/6, sendmsg4/6 and recvmsg4/6 hooks.
* Patch 5 makes the set of socket operations for each test case
configurable, laying the groundwork for Patch 6.
* Patch 6 introduces two sets of sock_ops that invoke the kernel
equivalents of connect(), bind(), etc. and uses these to add coverage
for the kernel socket functions.
=======
Changes
=======
v2->v3
------
* Renamed bind helpers. Dropped "_ntoh" suffix.
* Added guards to kfuncs to make sure addrlen and msglen do not exceed
the buffer capacity.
* Added KF_SLEEPABLE flag to kfuncs.
* Added a mutex (sock_lock) to kfuncs to serialize access to sock.
* Added NULL check for sock to each kfunc.
* Use the "sock_addr" networking namespace for all network interface
setup and testing.
* Use "nodad" when calling "ip -6 addr add" during interface setup to
avoid delays and remove ping loop.
* Removed test cases from test_sock_addr.c to make it clear what remains
to be migrated.
* Removed unused parameter (expect_change) from sock_addr_op().
Link: https://lore.kernel.org/bpf/20240412165230.2009746-1-jrife@google.com/T/#u
v1->v2
------
* Dropped test_progs/sock_addr_kern.c and the sock_addr_kern test module
in favor of simply expanding bpf_testmod and test_progs/sock_addr.c.
* Migrated environment setup logic from bpf/test_sock_addr.sh into
prog_tests/sock_addr.c rather than invoking the script from the test
program.
* Added kfuncs to bpf_testmod as well as the sock_addr_kern BPF program
to enable us to invoke kernel socket functions from
test_progs/sock_addr.c.
* Added test coverage for kernel socket functions to
test_progs/sock_addr.c.
Link: https://lore.kernel.org/bpf/20240329191907.1808635-1-jrife@google.com/T/#u
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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This patch creates two sets of sock_ops that call out to the SYSCALL
hooks in the sock_addr_kern BPF program and uses them to construct
test cases for the range of supported operations (kernel_connect(),
kernel_bind(), kernel_sendms(), sock_sendmsg(), kernel_getsockname(),
kenel_getpeername()). This ensures that these interact with BPF sockaddr
hooks as intended.
Beyond this it also ensures that these operations do not modify their
address parameter, providing regression coverage for the issues
addressed by this set of patches:
- commit 0bdf399342c5("net: Avoid address overwrite in kernel_connect")
- commit 86a7e0b69bd5("net: prevent rewrite of msg_name in sock_sendmsg()")
- commit c889a99a21bf("net: prevent address rewrite in kernel_bind()")
- commit 01b2885d9415("net: Save and restore msg_namelen in sock_sendmsg")
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240429214529.2644801-7-jrife@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
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In order to reuse the same test code for both socket system calls (e.g.
connect(), bind(), etc.) and kernel socket functions (e.g.
kernel_connect(), kernel_bind(), etc.), this patch introduces the "ops"
field to sock_addr_test. This field allows each test cases to configure
the set of functions used in the test case to create, manipulate, and
tear down a socket.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240429214529.2644801-6-jrife@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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This patch lays the groundwork for testing IPv4 and IPv6 sockaddr hooks
and their interaction with both socket syscalls and kernel functions
(e.g. kernel_connect, kernel_bind, etc.). It moves some of the test
cases from the old-style bpf/test_sock_addr.c self test into the
sock_addr prog_test in a step towards fully retiring
bpf/test_sock_addr.c. We will expand the test dimensions in the
sock_addr prog_test in a later patch series in order to migrate the
remaining test cases.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240429214529.2644801-5-jrife@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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This patch lays out a set of SYSCALL programs that can be used to invoke
the socket operation kfuncs in bpf_testmod, allowing a test program to
manipulate kernel socket operations from userspace.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240429214529.2644801-4-jrife@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
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This patch adds a set of kfuncs to bpf_testmod that can be used to
manipulate a socket from kernel space.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240429214529.2644801-3-jrife@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
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Without this fix, the bind4 and bind6 programs will reject bind attempts
on big endian systems. This patch ensures that CI tests pass for the
s390x architecture.
Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240429214529.2644801-2-jrife@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
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tools/lib/bpf/Makefile assumes that the patch in OUTPUT is a directory
and that it includes a trailing slash. This seems to be a common
expectation for OUTPUT among all the Makefiles.
In the rule for runqslower in tools/testing/selftests/bpf/Makefile the
variable BPFTOOL_OUTPUT is set to a directory name that lacks a
trailing slash. This results in a malformed BPF_HELPER_DEFS being
defined in lib/bpf/Makefile.
This problem becomes evident when a file like
tools/lib/bpf/bpf_tracing.h gets updated.
This patch fixes the problem by adding the missing slash in the value
for BPFTOOL_OUTPUT in the $(OUTPUT)/runqslower rule.
Regtested by running selftests in bpf-next master and building
samples/bpf programs.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240502140831.23915-1-jose.marchesi@oracle.com
|
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We just failed to retrieve pattern, so we need to print spec instead.
Fixes: ddc6b04989eb ("libbpf: Add bpf_program__attach_kprobe_multi_opts function")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240502075541.1425761-2-jolsa@kernel.org
|
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We just failed to retrieve pattern, so we need to print spec instead.
Fixes: 2ca178f02b2f ("libbpf: Add support for kprobe session attach")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240502075541.1425761-1-jolsa@kernel.org
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Crypto subsytem can be build as a module. In this case we still have to
build BPF crypto framework otherwise the build will fail.
Fixes: 3e1c6f35409f ("bpf: make common crypto API for TC/XDP programs")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202405011634.4JK40epY-lkp@intel.com/
Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Link: https://lore.kernel.org/r/20240501170130.1682309-1-vadfed@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
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Previous attempt to fix the handling of nulled-out (from skeleton)
struct_ops program is working well only if struct_ops program is defined
as non-autoloaded by default (i.e., has SEC("?struct_ops") annotation,
with question mark).
Unfortunately, that fix is incomplete due to how
bpf_object_adjust_struct_ops_autoload() is marking referenced or
non-referenced struct_ops program as autoloaded (or not). Because
bpf_object_adjust_struct_ops_autoload() is run after
bpf_map__init_kern_struct_ops() step, which sets program slot to NULL,
such programs won't be considered "referenced", and so its autoload
property won't be changed.
This all sounds convoluted and it is, but the desire is to have as
natural behavior (as far as struct_ops usage is concerned) as possible.
This fix is redoing the original fix but makes it work for
autoloaded-by-default struct_ops programs as well. We achieve this by
forcing prog->autoload to false if prog was declaratively set for some
struct_ops map, but then nulled-out from skeleton (programmatically).
This achieves desired effect of not autoloading it. If such program is
still referenced somewhere else (different struct_ops map or different
callback field), it will get its autoload property adjusted by
bpf_object_adjust_struct_ops_autoload() later.
We also fix selftest, which accidentally used SEC("?struct_ops")
annotation. It was meant to use autoload-by-default program from the
very beginning.
Fixes: f973fccd43d3 ("libbpf: handle nulled-out program in struct_ops correctly")
Cc: Kui-Feng Lee <thinker.li@gmail.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240501041706.3712608-1-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Viktor Malik says:
====================
libbpf: support "module:function" syntax for tracing programs
In some situations, it is useful to explicitly specify a kernel module
to search for a tracing program target (e.g. when a function of the same
name exists in multiple modules or in vmlinux).
This change enables that by allowing the "module:function" syntax for
the find_kernel_btf_id function. Thanks to this, the syntax can be used
both from a SEC macro (i.e. `SEC(fentry/module:function)`) and via the
bpf_program__set_attach_target API call.
---
Changes in v2:
- stylistic changes (suggested by Andrii)
- added Andrii's ack to the second patch
====================
Link: https://lore.kernel.org/r/cover.1714469650.git.vmalik@redhat.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
|
|
The previous patch added support for the "module:function" syntax for
tracing programs. This adds tests for explicitly specifying the module
name via the SEC macro and via the bpf_program__set_attach_target call.
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/8a076168ed847f7c8a6c25715737b1fea84e38be.1714469650.git.vmalik@redhat.com
|
|
In some situations, it is useful to explicitly specify a kernel module
to search for a tracing program target (e.g. when a function of the same
name exists in multiple modules or in vmlinux).
This patch enables that by allowing the "module:function" syntax for the
find_kernel_btf_id function. Thanks to this, the syntax can be used both
from a SEC macro (i.e. `SEC(fentry/module:function)`) and via the
bpf_program__set_attach_target API call.
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/9085a8cb9a552de98e554deb22ff7e977d025440.1714469650.git.vmalik@redhat.com
|