- 28 Oct, 2021 11 commits
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Kumar Kartikeya Dwivedi authored
Add a simple wrapper for passing an fd and getting a new one >= 3 if it is one of 0, 1, or 2. There are two primary reasons to make this change: First, libbpf relies on the assumption a certain BPF fd is never 0 (e.g. most recently noticed in [0]). Second, Alexei pointed out in [1] that some environments reset stdin, stdout, and stderr if they notice an invalid fd at these numbers. To protect against both these cases, switch all internal BPF syscall wrappers in libbpf to always return an fd >= 3. We only need to modify the syscall wrappers and not other code that assumes a valid fd by doing >= 0, to avoid pointless churn, and because it is still a valid assumption. The cost paid is two additional syscalls if fd is in range [0, 2]. [0]: e31eec77 ("bpf: selftests: Fix fd cleanup in get_branch_snapshot") [1]: https://lore.kernel.org/bpf/CAADnVQKVKY8o_3aU8Gzke443+uHa-eGoM0h7W4srChMXU1S4Bg@mail.gmail.comSigned-off-by:
Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org> Acked-by:
Song Liu <songliubraving@fb.com> Acked-by:
Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211028063501.2239335-5-memxor@gmail.com
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Kumar Kartikeya Dwivedi authored
This extends existing ksym relocation code to also support relocating weak ksyms. Care needs to be taken to zero out the src_reg (currently BPF_PSEUOD_BTF_ID, always set for gen_loader by bpf_object__relocate_data) when the BTF ID lookup fails at runtime. This is not a problem for libbpf as it only sets ext->is_set when BTF ID lookup succeeds (and only proceeds in case of failure if ext->is_weak, leading to src_reg remaining as 0 for weak unresolved ksym). A pattern similar to emit_relo_kfunc_btf is followed of first storing the default values and then jumping over actual stores in case of an error. For src_reg adjustment, we also need to perform it when copying the populated instruction, so depending on if copied insn[0].imm is 0 or not, we decide to jump over the adjustment. We cannot reach that point unless the ksym was weak and resolved and zeroed out, as the emit_check_err will cause us to jump to cleanup label, so we do not need to recheck whether the ksym is weak before doing the adjustment after copying BTF ID and BTF FD. This is consistent with how libbpf relocates weak ksym. Logging statements are added to show the relocation result and aid debugging. Signed-off-by:
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Kumar Kartikeya Dwivedi authored
This uses the bpf_kallsyms_lookup_name helper added in previous patches to relocate typeless ksyms. The return value ENOENT can be ignored, and the value written to 'res' can be directly stored to the insn, as it is overwritten to 0 on lookup failure. For repeating symbols, we can simply copy the previously populated bpf_insn. Also, we need to take care to not close fds for typeless ksym_desc, so reuse the 'off' member's space to add a marker for typeless ksym and use that to skip them in cleanup_relos. We add a emit_ksym_relo_log helper that avoids duplicating common logging instructions between typeless and weak ksym (for future commit). Signed-off-by:
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Kumar Kartikeya Dwivedi authored
This helper allows us to get the address of a kernel symbol from inside a BPF_PROG_TYPE_SYSCALL prog (used by gen_loader), so that we can relocate typeless ksym vars. Signed-off-by:
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Alexei Starovoitov authored
Joanne Koong says: ==================== This patchset adds a new kind of bpf map: the bloom filter map. Bloom filters are a space-efficient probabilistic data structure used to quickly test whether an element exists in a set. For a brief overview about how bloom filters work, https://en.wikipedia.org/wiki/Bloom_filter may be helpful. One example use-case is an application leveraging a bloom filter map to determine whether a computationally expensive hashmap lookup can be avoided. If the element was not found in the bloom filter map, the hashmap lookup can be skipped. This patchset includes benchmarks for testing the performance of the bloom filter for different entry sizes and different number of hash functions used, as well as comparisons for hashmap lookups with vs. without the bloom filter. A high level overview of this patchset is as follows: 1/5 - kernel changes for adding bloom filter map 2/5 - libbpf changes for adding map_extra flags 3/5 - tests for the bloom filter map 4/5 - benchmarks for bloom filter lookup/update throughput and false positive rate 5/5 - benchmarks for how hashmap lookups perform with vs. without the bloom filter v5 -> v6: * in 1/5: remove "inline" from the hash function, add check in syscall to fail out in cases where map_extra is not 0 for non-bloom-filter maps, fix alignment matching issues, move "map_extra flags" comments to inside the bpf_attr struct, add bpf_map_info map_extra changes here, add map_extra assignment in bpf_map_get_info_by_fd, change hash value_size to u32 instead of a u64 * in 2/5: remove bpf_map_info map_extra changes, remove TODO comment about extending BTF arrays to cover u64s, cast to unsigned long long for %llx when printing out map_extra flags * in 3/5: use __type(value, ...) instead of __uint(value_size, ...) for values and keys * in 4/5: fix wrong bounds for the index when iterating through random values, update commit message to include update+lookup benchmark results for 8 byte and 64-byte value sizes, remove explicit global bool initializaton to false for hashmap_use_bloom and count_false_hits variables v4 -> v5: * Change the "bitset map with bloom filter capabilities" to a bloom filter map with max_entries signifying the number of unique entries expected in the bloom filter, remove bitset tests * Reduce verbiage by changing "bloom_filter" to "bloom", and renaming progs to more concise names. * in 2/5: remove "map_extra" from struct definitions that are frozen, create a "bpf_create_map_params" struct to propagate map_extra to the kernel at map creation time, change map_extra to __u64 * in 4/5: check pthread condition variable in a loop when generating initial map data, remove "err" checks where not pragmatic, generate random values for the hashmap in the setup() instead of in the bpf program, add check_args() for checking that there aren't more requested entries than possible unique entries for the specified value size * in 5/5: Update commit message with updated benchmark data v3 -> v4: * Generalize the bloom filter map to be a bitset map with bloom filter capabilities * Add map_extra flags; pass in nr_hash_funcs through lower 4 bits of map_extra for the bitset map * Add tests for the bitset map (non-bloom filter) functionality * In the benchmarks, stats are computed only as monotonic increases, and place stats in a struct instead of as a percpu_array bpf map v2 -> v3: * Add libbpf changes for supporting nr_hash_funcs, instead of passing the number of hash functions through map_flags. * Separate the hashing logic in kernel/bpf/bloom_filter.c into a helper function v1 -> v2: * Remove libbpf changes, and pass the number of hash functions through map_flags instead. * Default to using 5 hash functions if no number of hash functions is specified. * Use set_bit instead of spinlocks in the bloom filter bitmap. This improved the speed significantly. For example, using 5 hash functions with 100k entries, there was roughly a 35% speed increase. * Use jhash2 (instead of jhash) for u32-aligned value sizes. This increased the speed by roughly 5 to 15%. When using jhash2 on value sizes non-u32 aligned (truncating any remainder bits), there was not a noticeable difference. * Add test for using the bloom filter as an inner map. * Reran the benchmarks, updated the commit messages to correspond to the new results. ==================== Acked-by:
Martin KaFai Lau <kafai@fb.com> Signed-off-by:
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Joanne Koong authored
This patch adds benchmark tests for comparing the performance of hashmap lookups without the bloom filter vs. hashmap lookups with the bloom filter. Checking the bloom filter first for whether the element exists should overall enable a higher throughput for hashmap lookups, since if the element does not exist in the bloom filter, we can avoid a costly lookup in the hashmap. On average, using 5 hash functions in the bloom filter tended to perform the best across the widest range of different entry sizes. The benchmark results using 5 hash functions (running on 8 threads on a machine with one numa node, and taking the average of 3 runs) were roughly as follows: value_size = 4 bytes - 10k entries: 30% faster 50k entries: 40% faster 100k entries: 40% faster 500k entres: 70% faster 1 million entries: 90% faster 5 million entries: 140% faster value_size = 8 bytes - 10k entries: 30% faster 50k entries: 40% faster 100k entries: 50% faster 500k entres: 80% faster 1 million entries: 100% faster 5 million entries: 150% faster value_size = 16 bytes - 10k entries: 20% faster 50k entries: 30% faster 100k entries: 35% faster 500k entres: 65% faster 1 million entries: 85% faster 5 million entries: 110% faster value_size = 40 bytes - 10k entries: 5% faster 50k entries: 15% faster 100k entries: 20% faster 500k entres: 65% faster 1 million entries: 75% faster 5 million entries: 120% faster Signed-off-by:
Joanne Koong <joannekoong@fb.com> Signed-off-by:
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Joanne Koong authored
This patch adds benchmark tests for the throughput (for lookups + updates) and the false positive rate of bloom filter lookups, as well as some minor refactoring of the bash script for running the benchmarks. These benchmarks show that as the number of hash functions increases, the throughput and the false positive rate of the bloom filter decreases. >From the benchmark data, the approximate average false-positive rates are roughly as follows: 1 hash function = ~30% 2 hash functions = ~15% 3 hash functions = ~5% 4 hash functions = ~2.5% 5 hash functions = ~1% 6 hash functions = ~0.5% 7 hash functions = ~0.35% 8 hash functions = ~0.15% 9 hash functions = ~0.1% 10 hash functions = ~0% For reference data, the benchmarks run on one thread on a machine with one numa node for 1 to 5 hash functions for 8-byte and 64-byte values are as follows: 1 hash function: 50k entries 8-byte value Lookups - 51.1 M/s operations Updates - 33.6 M/s operations False positive rate: 24.15% 64-byte value Lookups - 15.7 M/s operations Updates - 15.1 M/s operations False positive rate: 24.2% 100k entries 8-byte value Lookups - 51.0 M/s operations Updates - 33.4 M/s operations False positive rate: 24.04% 64-byte value Lookups - 15.6 M/s operations Updates - 14.6 M/s operations False positive rate: 24.06% 500k entries 8-byte value Lookups - 50.5 M/s operations Updates - 33.1 M/s operations False positive rate: 27.45% 64-byte value Lookups - 15.6 M/s operations Updates - 14.2 M/s operations False positive rate: 27.42% 1 mil entries 8-byte value Lookups - 49.7 M/s operations Updates - 32.9 M/s operations False positive rate: 27.45% 64-byte value Lookups - 15.4 M/s operations Updates - 13.7 M/s operations False positive rate: 27.58% 2.5 mil entries 8-byte value Lookups - 47.2 M/s operations Updates - 31.8 M/s operations False positive rate: 30.94% 64-byte value Lookups - 15.3 M/s operations Updates - 13.2 M/s operations False positive rate: 30.95% 5 mil entries 8-byte value Lookups - 41.1 M/s operations Updates - 28.1 M/s operations False positive rate: 31.01% 64-byte value Lookups - 13.3 M/s operations Updates - 11.4 M/s operations False positive rate: 30.98% 2 hash functions: 50k entries 8-byte value Lookups - 34.1 M/s operations Updates - 20.1 M/s operations False positive rate: 9.13% 64-byte value Lookups - 8.4 M/s operations Updates - 7.9 M/s operations False positive rate: 9.21% 100k entries 8-byte value Lookups - 33.7 M/s operations Updates - 18.9 M/s operations False positive rate: 9.13% 64-byte value Lookups - 8.4 M/s operations Updates - 7.7 M/s operations False positive rate: 9.19% 500k entries 8-byte value Lookups - 32.7 M/s operations Updates - 18.1 M/s operations False positive rate: 12.61% 64-byte value Lookups - 8.4 M/s operations Updates - 7.5 M/s operations False positive rate: 12.61% 1 mil entries 8-byte value Lookups - 30.6 M/s operations Updates - 18.9 M/s operations False positive rate: 12.54% 64-byte value Lookups - 8.0 M/s operations Updates - 7.0 M/s operations False positive rate: 12.52% 2.5 mil entries 8-byte value Lookups - 25.3 M/s operations Updates - 16.7 M/s operations False positive rate: 16.77% 64-byte value Lookups - 7.9 M/s operations Updates - 6.5 M/s operations False positive rate: 16.88% 5 mil entries 8-byte value Lookups - 20.8 M/s operations Updates - 14.7 M/s operations False positive rate: 16.78% 64-byte value Lookups - 7.0 M/s operations Updates - 6.0 M/s operations False positive rate: 16.78% 3 hash functions: 50k entries 8-byte value Lookups - 25.1 M/s operations Updates - 14.6 M/s operations False positive rate: 7.65% 64-byte value Lookups - 5.8 M/s operations Updates - 5.5 M/s operations False positive rate: 7.58% 100k entries 8-byte value Lookups - 24.7 M/s operations Updates - 14.1 M/s operations False positive rate: 7.71% 64-byte value Lookups - 5.8 M/s operations Updates - 5.3 M/s operations False positive rate: 7.62% 500k entries 8-byte value Lookups - 22.9 M/s operations Updates - 13.9 M/s operations False positive rate: 2.62% 64-byte value Lookups - 5.6 M/s operations Updates - 4.8 M/s operations False positive rate: 2.7% 1 mil entries 8-byte value Lookups - 19.8 M/s operations Updates - 12.6 M/s operations False positive rate: 2.60% 64-byte value Lookups - 5.3 M/s operations Updates - 4.4 M/s operations False positive rate: 2.69% 2.5 mil entries 8-byte value Lookups - 16.2 M/s operations Updates - 10.7 M/s operations False positive rate: 4.49% 64-byte value Lookups - 4.9 M/s operations Updates - 4.1 M/s operations False positive rate: 4.41% 5 mil entries 8-byte value Lookups - 18.8 M/s operations Updates - 9.2 M/s operations False positive rate: 4.45% 64-byte value Lookups - 5.2 M/s operations Updates - 3.9 M/s operations False positive rate: 4.54% 4 hash functions: 50k entries 8-byte value Lookups - 19.7 M/s operations Updates - 11.1 M/s operations False positive rate: 1.01% 64-byte value Lookups - 4.4 M/s operations Updates - 4.0 M/s operations False positive rate: 1.00% 100k entries 8-byte value Lookups - 19.5 M/s operations Updates - 10.9 M/s operations False positive rate: 1.00% 64-byte value Lookups - 4.3 M/s operations Updates - 3.9 M/s operations False positive rate: 0.97% 500k entries 8-byte value Lookups - 18.2 M/s operations Updates - 10.6 M/s operations False positive rate: 2.05% 64-byte value Lookups - 4.3 M/s operations Updates - 3.7 M/s operations False positive rate: 2.05% 1 mil entries 8-byte value Lookups - 15.5 M/s operations Updates - 9.6 M/s operations False positive rate: 1.99% 64-byte value Lookups - 4.0 M/s operations Updates - 3.4 M/s operations False positive rate: 1.99% 2.5 mil entries 8-byte value Lookups - 13.8 M/s operations Updates - 7.7 M/s operations False positive rate: 3.91% 64-byte value Lookups - 3.7 M/s operations Updates - 3.6 M/s operations False positive rate: 3.78% 5 mil entries 8-byte value Lookups - 13.0 M/s operations Updates - 6.9 M/s operations False positive rate: 3.93% 64-byte value Lookups - 3.5 M/s operations Updates - 3.7 M/s operations False positive rate: 3.39% 5 hash functions: 50k entries 8-byte value Lookups - 16.4 M/s operations Updates - 9.1 M/s operations False positive rate: 0.78% 64-byte value Lookups - 3.5 M/s operations Updates - 3.2 M/s operations False positive rate: 0.77% 100k entries 8-byte value Lookups - 16.3 M/s operations Updates - 9.0 M/s operations False positive rate: 0.79% 64-byte value Lookups - 3.5 M/s operations Updates - 3.2 M/s operations False positive rate: 0.78% 500k entries 8-byte value Lookups - 15.1 M/s operations Updates - 8.8 M/s operations False positive rate: 1.82% 64-byte value Lookups - 3.4 M/s operations Updates - 3.0 M/s operations False positive rate: 1.78% 1 mil entries 8-byte value Lookups - 13.2 M/s operations Updates - 7.8 M/s operations False positive rate: 1.81% 64-byte value Lookups - 3.2 M/s operations Updates - 2.8 M/s operations False positive rate: 1.80% 2.5 mil entries 8-byte value Lookups - 10.5 M/s operations Updates - 5.9 M/s operations False positive rate: 0.29% 64-byte value Lookups - 3.2 M/s operations Updates - 2.4 M/s operations False positive rate: 0.28% 5 mil entries 8-byte value Lookups - 9.6 M/s operations Updates - 5.7 M/s operations False positive rate: 0.30% 64-byte value Lookups - 3.2 M/s operations Updates - 2.7 M/s operations False positive rate: 0.30% Signed-off-by:
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Joanne Koong authored
This patch adds test cases for bpf bloom filter maps. They include tests checking against invalid operations by userspace, tests for using the bloom filter map as an inner map, and a bpf program that queries the bloom filter map for values added by a userspace program. Signed-off-by:
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Joanne Koong authored
This patch adds the libbpf infrastructure for supporting a per-map-type "map_extra" field, whose definition will be idiosyncratic depending on map type. For example, for the bloom filter map, the lower 4 bits of map_extra is used to denote the number of hash functions. Please note that until libbpf 1.0 is here, the "bpf_create_map_params" struct is used as a temporary means for propagating the map_extra field to the kernel. Signed-off-by:
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Joanne Koong authored
This patch adds the kernel-side changes for the implementation of a bpf bloom filter map. The bloom filter map supports peek (determining whether an element is present in the map) and push (adding an element to the map) operations.These operations are exposed to userspace applications through the already existing syscalls in the following way: BPF_MAP_LOOKUP_ELEM -> peek BPF_MAP_UPDATE_ELEM -> push The bloom filter map does not have keys, only values. In light of this, the bloom filter map's API matches that of queue stack maps: user applications use BPF_MAP_LOOKUP_ELEM/BPF_MAP_UPDATE_ELEM which correspond internally to bpf_map_peek_elem/bpf_map_push_elem, and bpf programs must use the bpf_map_peek_elem and bpf_map_push_elem APIs to query or add an element to the bloom filter map. When the bloom filter map is created, it must be created with a key_size of 0. For updates, the user will pass in the element to add to the map as the value, with a NULL key. For lookups, the user will pass in the element to query in the map as the value, with a NULL key. In the verifier layer, this requires us to modify the argument type of a bloom filter's BPF_FUNC_map_peek_elem call to ARG_PTR_TO_MAP_VALUE; as well, in the syscall layer, we need to copy over the user value so that in bpf_map_peek_elem, we know which specific value to query. A few things to please take note of: * If there are any concurrent lookups + updates, the user is responsible for synchronizing this to ensure no false negative lookups occur. * The number of hashes to use for the bloom filter is configurable from userspace. If no number is specified, the default used will be 5 hash functions. The benchmarks later in this patchset can help compare the performance of using different number of hashes on different entry sizes. In general, using more hashes decreases both the false positive rate and the speed of a lookup. * Deleting an element in the bloom filter map is not supported. * The bloom filter map may be used as an inner map. * The "max_entries" size that is specified at map creation time is used to approximate a reasonable bitmap size for the bloom filter, and is not otherwise strictly enforced. If the user wishes to insert more entries into the bloom filter than "max_entries", they may do so but they should be aware that this may lead to a higher false positive rate. Signed-off-by:
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Tiezhu Yang authored
After commit 9298e63e ("bpf/tests: Add exhaustive tests of ALU operand magnitudes"), when modprobe test_bpf.ko with JIT on mips64, there exists segment fault due to the following reason: [...] ALU64_MOV_X: all register value magnitudes jited:1 Break instruction in kernel code[#1] [...] It seems that the related JIT implementations of some test cases in test_bpf() have problems. At this moment, I do not care about the segment fault while I just want to verify the test cases of tail calls. Based on the above background and motivation, add the following module parameter test_suite to the test_bpf.ko: test_suite=<string>: only the specified test suite will be run, the string can be "test_bpf", "test_tail_calls" or "test_skb_segment". If test_suite is not specified, but test_id, test_name or test_range is specified, set 'test_bpf' as the default test suite. This is useful to only test the corresponding test suite when specifying the valid test_suite string. Any invalid test suite will result in -EINVAL being returned and no tests being run. If the test_suite is not specified or specified as empty string, it does not change the current logic, all of the test cases will be run. Here are some test results: # dmesg -c # modprobe test_bpf # dmesg | grep Summary test_bpf: Summary: 1009 PASSED, 0 FAILED, [0/997 JIT'ed] test_bpf: test_tail_calls: Summary: 8 PASSED, 0 FAILED, [0/8 JIT'ed] test_bpf: test_skb_segment: Summary: 2 PASSED, 0 FAILED # rmmod test_bpf # dmesg -c # modprobe test_bpf test_suite=test_bpf # dmesg | tail -1 test_bpf: Summary: 1009 PASSED, 0 FAILED, [0/997 JIT'ed] # rmmod test_bpf # dmesg -c # modprobe test_bpf test_suite=test_tail_calls # dmesg test_bpf: #0 Tail call leaf jited:0 21 PASS [...] test_bpf: #7 Tail call error path, index out of range jited:0 32 PASS test_bpf: test_tail_calls: Summary: 8 PASSED, 0 FAILED, [0/8 JIT'ed] # rmmod test_bpf # dmesg -c # modprobe test_bpf test_suite=test_skb_segment # dmesg test_bpf: #0 gso_with_rx_frags PASS test_bpf: #1 gso_linear_no_head_frag PASS test_bpf: test_skb_segment: Summary: 2 PASSED, 0 FAILED # rmmod test_bpf # dmesg -c # modprobe test_bpf test_id=1 # dmesg test_bpf: test_bpf: set 'test_bpf' as the default test_suite. test_bpf: #1 TXA jited:0 54 51 50 PASS test_bpf: Summary: 1 PASSED, 0 FAILED, [0/1 JIT'ed] # rmmod test_bpf # dmesg -c # modprobe test_bpf test_suite=test_bpf test_name=TXA # dmesg test_bpf: #1 TXA jited:0 54 50 51 PASS test_bpf: Summary: 1 PASSED, 0 FAILED, [0/1 JIT'ed] # rmmod test_bpf # dmesg -c # modprobe test_bpf test_suite=test_tail_calls test_range=6,7 # dmesg test_bpf: #6 Tail call error path, NULL target jited:0 41 PASS test_bpf: #7 Tail call error path, index out of range jited:0 32 PASS test_bpf: test_tail_calls: Summary: 2 PASSED, 0 FAILED, [0/2 JIT'ed] # rmmod test_bpf # dmesg -c # modprobe test_bpf test_suite=test_skb_segment test_id=1 # dmesg test_bpf: #1 gso_linear_no_head_frag PASS test_bpf: test_skb_segment: Summary: 1 PASSED, 0 FAILED By the way, the above segment fault has been fixed in the latest bpf-next tree which contains the mips64 JIT rework. Signed-off-by:
Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Tested-by:
Johan Almbladh <johan.almbladh@anyfinetworks.com> Acked-by:
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- 27 Oct, 2021 10 commits
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Tong Tiangen authored
When a tracing BPF program attempts to read memory without using the bpf_probe_read() helper, the verifier marks the load instruction with the BPF_PROBE_MEM flag. Since the riscv JIT does not currently recognize this flag it falls back to the interpreter. Add support for BPF_PROBE_MEM, by appending an exception table to the BPF program. If the load instruction causes a data abort, the fixup infrastructure finds the exception table and fixes up the fault, by clearing the destination register and jumping over the faulting instruction. A more generic solution would add a "handler" field to the table entry, like on x86 and s390. The same issue in ARM64 is fixed in 80083428 ("bpf, arm64: Add BPF exception tables"). Signed-off-by:
Tong Tiangen <tongtiangen@huawei.com> Signed-off-by:
Pu Lehui <pulehui@huawei.com> Tested-by:
Björn Töpel <bjorn@kernel.org> Acked-by:
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Andrii Nakryiko authored
Yucong Sun says: ==================== Several patches to improve parallel execution mode, updating vmtest.sh and fixed two previously dropped patches according to feedback. ==================== Signed-off-by: -
Yucong Sun authored
This patch delete ns_src/ns_dst/ns_redir namespaces before recreating them, making the test more robust. Signed-off-by:
Yucong Sun <sunyucong@gmail.com> Signed-off-by:
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Yucong Sun authored
This patch makes attach_probe uses its own method as attach point, avoiding conflict with other tests like bpf_cookie. Signed-off-by:
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Yucong Sun authored
Increase memory to 4G, 8 SMP core with host cpu passthrough. This make it run faster in parallel mode and more likely to succeed. Signed-off-by:
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Alexei Starovoitov authored
Eric Dumazet says: ==================== From: Eric Dumazet <edumazet@google.com> Two first patches fix bugs added in 5.1 and 5.5 Third patch replaces the u64 fields in struct bpf_prog_stats with u64_stats_t ones to avoid possible sampling errors, in case of load/store stearing. ==================== Signed-off-by: -
Eric Dumazet authored
Commit 316580b6 ("u64_stats: provide u64_stats_t type") fixed possible load/store tearing on 64bit arches. For instance the following C code stats->nsecs += sched_clock() - start; Could be rightfully implemented like this by a compiler, confusing concurrent readers a lot: stats->nsecs += sched_clock(); // arbitrary delay stats->nsecs -= start; Signed-off-by:
Eric Dumazet <edumazet@google.com> Signed-off-by:
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Eric Dumazet authored
It seems update_prog_stats() suffers from same issue fixed in the prior patch: As it can run while interrupts are enabled, it could be re-entered and the u64_stats syncp could be mangled. Fixes: fec56f58 ("bpf: Introduce BPF trampoline") Signed-off-by:
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Eric Dumazet authored
__bpf_prog_run() can run from non IRQ contexts, meaning it could be re entered if interrupted. This calls for the irq safe variant of u64_stats_update_{begin|end}, or risk a deadlock. This patch is a nop on 64bit arches, fortunately. syzbot report: WARNING: inconsistent lock state 5.12.0-rc3-syzkaller #0 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. udevd/4013 [HC0[0]:SC0[0]:HE1:SE1] takes: ff7c9dec (&(&pstats->syncp)->seq){+.?.}-{0:0}, at: sk_filter include/linux/filter.h:867 [inline] ff7c9dec (&(&pstats->syncp)->seq){+.?.}-{0:0}, at: do_one_broadcast net/netlink/af_netlink.c:1468 [inline] ff7c9dec (&(&pstats->syncp)->seq){+.?.}-{0:0}, at: netlink_broadcast_filtered+0x27c/0x4fc net/netlink/af_netlink.c:1520 {IN-SOFTIRQ-W} state was registered at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 do_write_seqcount_begin_nested include/linux/seqlock.h:520 [inline] do_write_seqcount_begin include/linux/seqlock.h:545 [inline] u64_stats_update_begin include/linux/u64_stats_sync.h:129 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:624 [inline] bpf_prog_run_clear_cb+0x1bc/0x270 include/linux/filter.h:755 run_filter+0xa0/0x17c net/packet/af_packet.c:2031 packet_rcv+0xc0/0x3e0 net/packet/af_packet.c:2104 dev_queue_xmit_nit+0x2bc/0x39c net/core/dev.c:2387 xmit_one net/core/dev.c:3588 [inline] dev_hard_start_xmit+0x94/0x518 net/core/dev.c:3609 sch_direct_xmit+0x11c/0x1f0 net/sched/sch_generic.c:313 qdisc_restart net/sched/sch_generic.c:376 [inline] __qdisc_run+0x194/0x7f8 net/sched/sch_generic.c:384 qdisc_run include/net/pkt_sched.h:136 [inline] qdisc_run include/net/pkt_sched.h:128 [inline] __dev_xmit_skb net/core/dev.c:3795 [inline] __dev_queue_xmit+0x65c/0xf84 net/core/dev.c:4150 dev_queue_xmit+0x14/0x18 net/core/dev.c:4215 neigh_resolve_output net/core/neighbour.c:1491 [inline] neigh_resolve_output+0x170/0x228 net/core/neighbour.c:1471 neigh_output include/net/neighbour.h:510 [inline] ip6_finish_output2+0x2e4/0x9fc net/ipv6/ip6_output.c:117 __ip6_finish_output net/ipv6/ip6_output.c:182 [inline] __ip6_finish_output+0x164/0x3f8 net/ipv6/ip6_output.c:161 ip6_finish_output+0x2c/0xb0 net/ipv6/ip6_output.c:192 NF_HOOK_COND include/linux/netfilter.h:290 [inline] ip6_output+0x74/0x294 net/ipv6/ip6_output.c:215 dst_output include/net/dst.h:448 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] NF_HOOK include/linux/netfilter.h:295 [inline] mld_sendpack+0x2a8/0x7e4 net/ipv6/mcast.c:1679 mld_send_cr net/ipv6/mcast.c:1975 [inline] mld_ifc_timer_expire+0x1e8/0x494 net/ipv6/mcast.c:2474 call_timer_fn+0xd0/0x570 kernel/time/timer.c:1431 expire_timers kernel/time/timer.c:1476 [inline] __run_timers kernel/time/timer.c:1745 [inline] run_timer_softirq+0x2e4/0x384 kernel/time/timer.c:1758 __do_softirq+0x204/0x7ac kernel/softirq.c:345 do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] invoke_softirq kernel/softirq.c:228 [inline] __irq_exit_rcu+0x1d8/0x200 kernel/softirq.c:422 irq_exit+0x10/0x3c kernel/softirq.c:446 __handle_domain_irq+0xb4/0x120 kernel/irq/irqdesc.c:692 handle_domain_irq include/linux/irqdesc.h:176 [inline] gic_handle_irq+0x84/0xac drivers/irqchip/irq-gic.c:370 __irq_svc+0x5c/0x94 arch/arm/kernel/entry-armv.S:205 debug_smp_processor_id+0x0/0x24 lib/smp_processor_id.c:53 rcu_read_lock_held_common kernel/rcu/update.c:108 [inline] rcu_read_lock_sched_held+0x24/0x7c kernel/rcu/update.c:123 trace_lock_acquire+0x24c/0x278 include/trace/events/lock.h:13 lock_acquire+0x3c/0x74 kernel/locking/lockdep.c:5481 rcu_lock_acquire include/linux/rcupdate.h:267 [inline] rcu_read_lock include/linux/rcupdate.h:656 [inline] avc_has_perm_noaudit+0x6c/0x260 security/selinux/avc.c:1150 selinux_inode_permission+0x140/0x220 security/selinux/hooks.c:3141 security_inode_permission+0x44/0x60 security/security.c:1268 inode_permission.part.0+0x5c/0x13c fs/namei.c:521 inode_permission fs/namei.c:494 [inline] may_lookup fs/namei.c:1652 [inline] link_path_walk.part.0+0xd4/0x38c fs/namei.c:2208 link_path_walk fs/namei.c:2189 [inline] path_lookupat+0x3c/0x1b8 fs/namei.c:2419 filename_lookup+0xa8/0x1a4 fs/namei.c:2453 user_path_at_empty+0x74/0x90 fs/namei.c:2733 do_readlinkat+0x5c/0x12c fs/stat.c:417 __do_sys_readlink fs/stat.c:450 [inline] sys_readlink+0x24/0x28 fs/stat.c:447 ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64 0x7eaa4974 irq event stamp: 298277 hardirqs last enabled at (298277): [<802000d0>] no_work_pending+0x4/0x34 hardirqs last disabled at (298276): [<8020c9b8>] do_work_pending+0x9c/0x648 arch/arm/kernel/signal.c:676 softirqs last enabled at (298216): [<8020167c>] __do_softirq+0x584/0x7ac kernel/softirq.c:372 softirqs last disabled at (298201): [<8024dff4>] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] softirqs last disabled at (298201): [<8024dff4>] invoke_softirq kernel/softirq.c:228 [inline] softirqs last disabled at (298201): [<8024dff4>] __irq_exit_rcu+0x1d8/0x200 kernel/softirq.c:422 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&pstats->syncp)->seq); <Interrupt> lock(&(&pstats->syncp)->seq); *** DEADLOCK *** 1 lock held by udevd/4013: #0: 82b09c5c (rcu_read_lock){....}-{1:2}, at: sk_filter_trim_cap+0x54/0x434 net/core/filter.c:139 stack backtrace: CPU: 1 PID: 4013 Comm: udevd Not tainted 5.12.0-rc3-syzkaller #0 Hardware name: ARM-Versatile Express Backtrace: [<81802550>] (dump_backtrace) from [<818027c4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:252) r7:00000080 r6:600d0093 r5:00000000 r4:82b58344 [<818027ac>] (show_stack) from [<81809e98>] (__dump_stack lib/dump_stack.c:79 [inline]) [<818027ac>] (show_stack) from [<81809e98>] (dump_stack+0xb8/0xe8 lib/dump_stack.c:120) [<81809de0>] (dump_stack) from [<81804a00>] (print_usage_bug.part.0+0x228/0x230 kernel/locking/lockdep.c:3806) r7:86bcb768 r6:81a0326c r5:830f96a8 r4:86bcb0c0 [<818047d8>] (print_usage_bug.part.0) from [<802bb1b8>] (print_usage_bug kernel/locking/lockdep.c:3776 [inline]) [<818047d8>] (print_usage_bug.part.0) from [<802bb1b8>] (valid_state kernel/locking/lockdep.c:3818 [inline]) [<818047d8>] (print_usage_bug.part.0) from [<802bb1b8>] (mark_lock_irq kernel/locking/lockdep.c:4021 [inline]) [<818047d8>] (print_usage_bug.part.0) from [<802bb1b8>] (mark_lock.part.0+0xc34/0x136c kernel/locking/lockdep.c:4478) r10:83278fe8 r9:82c6d748 r8:00000000 r7:82c6d2d4 r6:00000004 r5:86bcb768 r4:00000006 [<802ba584>] (mark_lock.part.0) from [<802bc644>] (mark_lock kernel/locking/lockdep.c:4442 [inline]) [<802ba584>] (mark_lock.part.0) from [<802bc644>] (mark_usage kernel/locking/lockdep.c:4391 [inline]) [<802ba584>] (mark_lock.part.0) from [<802bc644>] (__lock_acquire+0x9bc/0x3318 kernel/locking/lockdep.c:4854) r10:86bcb768 r9:86bcb0c0 r8:00000001 r7:00040000 r6:0000075a r5:830f96a8 r4:00000000 [<802bbc88>] (__lock_acquire) from [<802bfb90>] (lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510) r10:00000000 r9:600d0013 r8:00000000 r7:00000000 r6:828a2680 r5:828a2680 r4:861e5bc8 [<802bfaa0>] (lock_acquire.part.0) from [<802bff28>] (lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483) r10:8146137c r9:00000000 r8:00000001 r7:00000000 r6:00000000 r5:00000000 r4:ff7c9dec [<802bfebc>] (lock_acquire) from [<81381eb4>] (do_write_seqcount_begin_nested include/linux/seqlock.h:520 [inline]) [<802bfebc>] (lock_acquire) from [<81381eb4>] (do_write_seqcount_begin include/linux/seqlock.h:545 [inline]) [<802bfebc>] (lock_acquire) from [<81381eb4>] (u64_stats_update_begin include/linux/u64_stats_sync.h:129 [inline]) [<802bfebc>] (lock_acquire) from [<81381eb4>] (__bpf_prog_run_save_cb include/linux/filter.h:727 [inline]) [<802bfebc>] (lock_acquire) from [<81381eb4>] (bpf_prog_run_save_cb include/linux/filter.h:741 [inline]) [<802bfebc>] (lock_acquire) from [<81381eb4>] (sk_filter_trim_cap+0x26c/0x434 net/core/filter.c:149) r10:a4095dd0 r9:ff7c9dd0 r8:e44be000 r7:8146137c r6:00000001 r5:8611ba80 r4:00000000 [<81381c48>] (sk_filter_trim_cap) from [<8146137c>] (sk_filter include/linux/filter.h:867 [inline]) [<81381c48>] (sk_filter_trim_cap) from [<8146137c>] (do_one_broadcast net/netlink/af_netlink.c:1468 [inline]) [<81381c48>] (sk_filter_trim_cap) from [<8146137c>] (netlink_broadcast_filtered+0x27c/0x4fc net/netlink/af_netlink.c:1520) r10:00000001 r9:833d6b1c r8:00000000 r7:8572f864 r6:8611ba80 r5:8698d800 r4:8572f800 [<81461100>] (netlink_broadcast_filtered) from [<81463e60>] (netlink_broadcast net/netlink/af_netlink.c:1544 [inline]) [<81461100>] (netlink_broadcast_filtered) from [<81463e60>] (netlink_sendmsg+0x3d0/0x478 net/netlink/af_netlink.c:1925) r10:00000000 r9:00000002 r8:8698d800 r7:000000b7 r6:8611b900 r5:861e5f50 r4:86aa3000 [<81463a90>] (netlink_sendmsg) from [<81321f54>] (sock_sendmsg_nosec net/socket.c:654 [inline]) [<81463a90>] (netlink_sendmsg) from [<81321f54>] (sock_sendmsg+0x3c/0x4c net/socket.c:674) r10:00000000 r9:861e5dd4 r8:00000000 r7:86570000 r6:00000000 r5:86570000 r4:861e5f50 [<81321f18>] (sock_sendmsg) from [<813234d0>] (____sys_sendmsg+0x230/0x29c net/socket.c:2350) r5:00000040 r4:861e5f50 [<813232a0>] (____sys_sendmsg) from [<8132549c>] (___sys_sendmsg+0xac/0xe4 net/socket.c:2404) r10:00000128 r9:861e4000 r8:00000000 r7:00000000 r6:86570000 r5:861e5f50 r4:00000000 [<813253f0>] (___sys_sendmsg) from [<81325684>] (__sys_sendmsg net/socket.c:2433 [inline]) [<813253f0>] (___sys_sendmsg) from [<81325684>] (__do_sys_sendmsg net/socket.c:2442 [inline]) [<813253f0>] (___sys_sendmsg) from [<81325684>] (sys_sendmsg+0x58/0xa0 net/socket.c:2440) r8:80200224 r7:00000128 r6:00000000 r5:7eaa541c r4:86570000 [<8132562c>] (sys_sendmsg) from [<80200060>] (ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64) Exception stack(0x861e5fa8 to 0x861e5ff0) 5fa0: 00000000 00000000 0000000c 7eaa541c 00000000 00000000 5fc0: 00000000 00000000 76fbf840 00000128 00000000 0000008f 7eaa541c 000563f8 5fe0: 00056110 7eaa53e0 00036cec 76c9bf44 r6:76fbf840 r5:00000000 r4:00000000 Fixes: 492ecee8 ("bpf: enable program stats") Reported-by:syzbot <syzkaller@googlegroups.com> Signed-off-by:
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Joe Burton authored
Add a flag to `enum libbpf_strict_mode' to disable the global `bpf_objects_list', preventing race conditions when concurrent threads call bpf_object__open() or bpf_object__close(). bpf_object__next() will return NULL if this option is set. Callers may achieve the same workflow by tracking bpf_objects in application code. [0] Closes: https://github.com/libbpf/libbpf/issues/293Signed-off-by:
Joe Burton <jevburton@google.com> Signed-off-by:
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- 26 Oct, 2021 19 commits
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Song Liu authored
Function in modules could appear in /proc/kallsyms in random order. ffffffffa02608a0 t bpf_testmod_loop_test ffffffffa02600c0 t __traceiter_bpf_testmod_test_writable_bare ffffffffa0263b60 d __tracepoint_bpf_testmod_test_write_bare ffffffffa02608c0 T bpf_testmod_test_read ffffffffa0260d08 t __SCT__tp_func_bpf_testmod_test_writable_bare ffffffffa0263300 d __SCK__tp_func_bpf_testmod_test_read ffffffffa0260680 T bpf_testmod_test_write ffffffffa0260860 t bpf_testmod_test_mod_kfunc Therefore, we cannot reliably use kallsyms_find_next() to find the end of a function. Replace it with a simple guess (start + 128). This is good enough for this test. Signed-off-by:
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Song Liu authored
Skipping the second half of the test is not enough to silent the warning in dmesg. Skip the whole test before we can either properly silent the warning in kernel, or fix LBR snapshot for VM. Fixes: 025bd7c7 ("selftests/bpf: Add test for bpf_get_branch_snapshot") Fixes: aa67fdb4 ("selftests/bpf: Skip the second half of get_branch_snapshot in vm") Signed-off-by:
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Andrii Nakryiko authored
Ilya Leoshkevich says: ==================== v2: https://lore.kernel.org/bpf/20211025131214.731972-1-iii@linux.ibm.com/ v2 -> v3: Split the fix from the cleanup (Daniel). v1: https://lore.kernel.org/bpf/20211021234653.643302-1-iii@linux.ibm.com/ v1 -> v2: Drop bpf_core_calc_field_relo() restructuring, split the __BYTE_ORDER__ change (Andrii). Hi, this series fixes test failures in core_reloc on s390. Patch 1 fixes an endianness bug with __BYTE_ORDER vs __BYTE_ORDER__. Patches 2-5 make the rest of the code consistent in that respect. Patch 6 fixes an endianness issue in test_core_reloc_mods. Best regards, Ilya ==================== Signed-off-by:
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Ilya Leoshkevich authored
This is the same as commit d164dd9a ("selftests/bpf: Fix test_core_autosize on big-endian machines"), but for test_core_reloc_mods. Signed-off-by:
Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by:
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Ilya Leoshkevich authored
Use the compiler-defined __BYTE_ORDER__ instead of the libc-defined __BYTE_ORDER for consistency. Signed-off-by:
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Ilya Leoshkevich authored
Use the compiler-defined __BYTE_ORDER__ instead of the libc-defined __BYTE_ORDER for consistency. Signed-off-by:
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Ilya Leoshkevich authored
Use the compiler-defined __BYTE_ORDER__ instead of the libc-defined __BYTE_ORDER for consistency. Signed-off-by:
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Ilya Leoshkevich authored
Use the compiler-defined __BYTE_ORDER__ instead of the libc-defined __BYTE_ORDER for consistency. Signed-off-by:
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Ilya Leoshkevich authored
__BYTE_ORDER is supposed to be defined by a libc, and __BYTE_ORDER__ - by a compiler. bpf_core_read.h checks __BYTE_ORDER == __LITTLE_ENDIAN, which is true if neither are defined, leading to incorrect behavior on big-endian hosts if libc headers are not included, which is often the case. Fixes: ee26dade ("libbpf: Add support for relocatable bitfields") Signed-off-by:
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Alexei Starovoitov authored
Andrii Nakryiko says: ==================== Add libbpf APIs to access BPF program instructions. Both before and after libbpf processing (before and after bpf_object__load()). This allows to inspect what's going on with BPF program assembly instructions as libbpf performs its processing magic. But in more practical terms, this allows to do a no-brainer BPF program cloning, which is something you need when working with fentry/fexit BPF programs to be able to attach the same BPF program code to multiple kernel functions. Currently, kernel needs multiple copies of BPF programs, each loaded with its own target BTF ID. retsnoop is one such example that previously had to rely on bpf_program__set_prep() API to hijack program instructions ([0] for before and after). Speaking of bpf_program__set_prep() API and the whole concept of multiple-instance BPF programs in libbpf, all that is scheduled for deprecation in v0.7. It doesn't work well, it's cumbersome, and it will become more broken as libbpf adds more functionality. So deprecate and remove it in libbpf 1.0. It doesn't seem to be used by anyone anyways (except for that retsnoop hack, which is now much cleaner with new APIs as can be seen in [0]). [0] https://github.com/anakryiko/retsnoop/pull/1 ==================== Signed-off-by:
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Andrii Nakryiko authored
The name of the API doesn't convey clearly that this size is in number of bytes (there needed to be a separate comment to make this clear in libbpf.h). Further, measuring the size of BPF program in bytes is not exactly the best fit, because BPF programs always consist of 8-byte instructions. As such, bpf_program__insn_cnt() is a better alternative in pretty much any imaginable case. So schedule bpf_program__size() deprecation starting from v0.7 and it will be removed in libbpf 1.0. Signed-off-by:
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Andrii Nakryiko authored
Schedule deprecation of a set of APIs that are related to multi-instance bpf_programs: - bpf_program__set_prep() ([0]); - bpf_program__{set,unset}_instance() ([1]); - bpf_program__nth_fd(). These APIs are obscure, very niche, and don't seem to be used much in practice. bpf_program__set_prep() is pretty useless for anything but the simplest BPF programs, as it doesn't allow to adjust BPF program load attributes, among other things. In short, it already bitrotted and will bitrot some more if not removed. With bpf_program__insns() API, which gives access to post-processed BPF program instructions of any given entry-point BPF program, it's now possible to do whatever necessary adjustments were possible with set_prep() API before, but also more. Given any such use case is automatically an advanced use case, requiring users to stick to low-level bpf_prog_load() APIs and managing their own prog FDs is reasonable. [0] Closes: https://github.com/libbpf/libbpf/issues/299 [1] Closes: https://github.com/libbpf/libbpf/issues/300Signed-off-by: -
Andrii Nakryiko authored
Add APIs providing read-only access to bpf_program BPF instructions ([0]). This is useful for diagnostics purposes, but it also allows a cleaner support for cloning BPF programs after libbpf did all the FD resolution and CO-RE relocations, subprog instructions appending, etc. Currently, cloning BPF program is possible only through hijacking a half-broken bpf_program__set_prep() API, which doesn't really work well for anything but most primitive programs. For instance, set_prep() API doesn't allow adjusting BPF program load parameters which are necessary for loading fentry/fexit BPF programs (the case where BPF program cloning is a necessity if doing some sort of mass-attachment functionality). Given bpf_program__set_prep() API is set to be deprecated, having a cleaner alternative is a must. libbpf internally already keeps track of linear array of struct bpf_insn, so it's not hard to expose it. The only gotcha is that libbpf previously freed instructions array during bpf_object load time, which would make this API much less useful overall, because in between bpf_object__open() and bpf_object__load() a lot of changes to instructions are done by libbpf. So this patch makes libbpf hold onto prog->insns array even after BPF program loading. I think this is a small price for added functionality and improved introspection of BPF program code. See retsnoop PR ([1]) for how it can be used in practice and code savings compared to relying on bpf_program__set_prep(). [0] Closes: https://github.com/libbpf/libbpf/issues/298 [1] https://github.com/anakryiko/retsnoop/pull/1Signed-off-by:
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Andrii Nakryiko authored
Fix instruction index validity check which has off-by-one error. Fixes: 3ee4f533 ("libbpf: Split bpf_core_apply_relo() into bpf_program independent helper.") Signed-off-by:
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Andrii Nakryiko authored
Quentin Monnet says: ==================== When listing BPF objects, bpftool can print a number of properties about items holding references to these objects. For example, it can show pinned paths for BPF programs, maps, and links; or programs and maps using a given BTF object; or the names and PIDs of processes referencing BPF objects. To collect this information, bpftool uses hash maps (to be clear: the data structures, inside bpftool - we are not talking of BPF maps). It uses the implementation available from the kernel, and picks it up from tools/include/linux/hashtable.h. This patchset converts bpftool's hash maps to a distinct implementation instead, the one coming with libbpf. The main motivation for this change is that it should ease the path towards a potential out-of-tree mirror for bpftool, like the one libbpf already has. Although it's not perfect to depend on libbpf's internal components, bpftool is intimately tied with the library anyway, and this looks better than depending too much on (non-UAPI) kernel headers. The first two patches contain preparatory work on the Makefile and on the initialisation of the hash maps for collecting pinned paths for objects. Then the transition is split into several steps, one for each kind of properties for which the collection is backed by hash maps. v2: - Move hashmap cleanup for pinned paths for links from do_detach() to do_show(). - Handle errors on hashmap__append() (in three of the patches). - Rename bpftool_hash_fn() and bpftool_equal_fn() as hash_fn_for_key_id() and equal_fn_for_key_id(), respectively. - Add curly braces for hashmap__for_each_key_entry() { } in show_btf_plain() and show_btf_json(), where the flow was difficult to read. ==================== Signed-off-by: -
Quentin Monnet authored
In order to show PIDs and names for processes holding references to BPF programs, maps, links, or BTF objects, bpftool creates hash maps to store all relevant information. This commit is part of a set that transitions from the kernel's hash map implementation to the one coming with libbpf. The motivation is to make bpftool less dependent of kernel headers, to ease the path to a potential out-of-tree mirror, like libbpf has. This is the third and final step of the transition, in which we convert the hash maps used for storing the information about the processes holding references to BPF objects (programs, maps, links, BTF), and at last we drop the inclusion of tools/include/linux/hashtable.h. Note: Checkpatch complains about the use of __weak declarations, and the missing empty lines after the bunch of empty function declarations when compiling without the BPF skeletons (none of these were introduced in this patch). We want to keep things as they are, and the reports should be safe to ignore. Signed-off-by:
Quentin Monnet <quentin@isovalent.com> Signed-off-by:
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Quentin Monnet authored
In order to show BPF programs and maps using BTF objects when the latter are being listed, bpftool creates hash maps to store all relevant items. This commit is part of a set that transitions from the kernel's hash map implementation to the one coming with libbpf. The motivation is to make bpftool less dependent of kernel headers, to ease the path to a potential out-of-tree mirror, like libbpf has. This commit focuses on the two hash maps used by bpftool when listing BTF objects to store references to programs and maps, and convert them to the libbpf's implementation. Signed-off-by:
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Quentin Monnet authored
In order to show pinned paths for BPF programs, maps, or links when listing them with the "-f" option, bpftool creates hash maps to store all relevant paths under the bpffs. So far, it would rely on the kernel implementation (from tools/include/linux/hashtable.h). We can make bpftool rely on libbpf's implementation instead. The motivation is to make bpftool less dependent of kernel headers, to ease the path to a potential out-of-tree mirror, like libbpf has. This commit is the first step of the conversion: the hash maps for pinned paths for programs, maps, and links are converted to libbpf's hashmap.{c,h}. Other hash maps used for the PIDs of process holding references to BPF objects are left unchanged for now. On the build side, this requires adding a dependency to a second header internal to libbpf, and making it a dependency for the bootstrap bpftool version as well. The rest of the changes are a rather straightforward conversion. Signed-off-by: -
Quentin Monnet authored
BPF programs, maps, and links, can all be listed with their pinned paths by bpftool, when the "-f" option is provided. To do so, bpftool builds hash maps containing all pinned paths for each kind of objects. These three hash maps are always initialised in main.c, and exposed through main.h. There appear to be no particular reason to do so: we can just as well make them static to the files that need them (prog.c, map.c, and link.c respectively), and initialise them only when we want to show objects and the "-f" switch is provided. This may prevent unnecessary memory allocations if the implementation of the hash maps was to change in the future. Signed-off-by:
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