- 21 Sep, 2020 8 commits
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Lorenz Bauer authored
Always check context access if the register we're operating on is PTR_TO_CTX, rather than relying on ARG_PTR_TO_CTX. This allows simplifying the arg_type checking section of the function. Signed-off-by:
Lorenz Bauer <lmb@cloudflare.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org> Acked-by:
Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200921121227.255763-8-lmb@cloudflare.com
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Lorenz Bauer authored
Instead of dealing with reg->ref_obj_id individually for every arg type that needs it, rely on the fact that ref_obj_id is zero if the register is not reference tracked. Signed-off-by:
Andrii Nakryiko <andriin@fb.com> Acked-by:
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Lorenz Bauer authored
Perform BTF type checks if the register we're working on contains a BTF pointer, rather than if the argument is for a BTF pointer. This is easier to understand, and allows removing the code from the arg_type checking section of the function. Signed-off-by:
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Lorenz Bauer authored
Function prototypes using ARG_PTR_TO_BTF_ID currently use two ways to signal which BTF IDs are acceptable. First, bpf_func_proto.btf_id is an array of IDs, one for each argument. This array is only accessed up to the highest numbered argument that uses ARG_PTR_TO_BTF_ID and may therefore be less than five arguments long. It usually points at a BTF_ID_LIST. Second, check_btf_id is a function pointer that is called by the verifier if present. It gets the actual BTF ID of the register, and the argument number we're currently checking. It turns out that the only user check_arg_btf_id ignores the argument, and is simply used to check whether the BTF ID has a struct sock_common at it's start. Replace both of these mechanisms with an explicit BTF ID for each argument in a function proto. Thanks to btf_struct_ids_match this is very flexible: check_arg_btf_id can be replaced by requiring struct sock_common. Signed-off-by:
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Lorenz Bauer authored
Add a convenience macro that allows defining a BTF ID list with a single item. This lets us cut down on repetitive macros. Suggested-by:
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Lorenz Bauer authored
Move the check for a NULL or zero register to check_helper_mem_access. This makes check_stack_boundary easier to understand. Signed-off-by:
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Lorenz Bauer authored
bsearch doesn't modify the contents of the array, so we can take a const pointer. Signed-off-by:
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Muchun Song authored
The in_atomic() macro cannot always detect atomic context, in particular, it cannot know about held spinlocks in non-preemptible kernels. Although, there is no user call bpf_link_put() with holding spinlock now, be on the safe side, so we can avoid this in the future. Signed-off-by:
Muchun Song <songmuchun@bytedance.com> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Acked-by:
Song Liu <songliubraving@fb.com> Acked-by:
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- 18 Sep, 2020 9 commits
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Martin KaFai Lau authored
The local_storage->list will be traversed by rcu reader in parallel. Thus, hlist_add_head_rcu() is needed in bpf_selem_link_storage_nolock(). This patch fixes it. This part of the code has recently been refactored in bpf-next and this patch makes changes to the new file "bpf_local_storage.c". Instead of using the original offending commit in the Fixes tag, the commit that created the file "bpf_local_storage.c" is used. A separate fix has been provided to the bpf tree. Fixes: 450af8d0 ("bpf: Split bpf_local_storage to bpf_sk_storage") Signed-off-by:
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Ilya Leoshkevich authored
s390 uses socketcall multiplexer instead of individual socket syscalls. Therefore, "kprobe/" SYSCALL(sys_connect) does not trigger and test_map_in_map fails. Fix by using "kprobe/__sys_connect" instead. Signed-off-by:
Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by:
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Ilya Leoshkevich authored
getsetsockopt() calls getsockopt() with optlen == 1, but then checks the resulting int. It is ok on little endian, but not on big endian. Fix by checking char instead. Fixes: 8a027dc0 ("selftests/bpf: add sockopt test that exercises sk helpers") Signed-off-by:
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Ilya Leoshkevich authored
server_map's value size is 8, but the test tries to put an int there. This sort of works on x86 (unless followed by non-0), but hard fails on s390. Fix by using __s64 instead of int. Fixes: 2d7824ff ("selftests: bpf: Add test for sk_assign") Signed-off-by:
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Maciej Fijalkowski authored
Add four tests to tailcalls selftest explicitly named "tailcall_bpf2bpf_X" as their purpose is to validate that combination of tailcalls with bpf2bpf calls are working properly. These tests also validate LD_ABS from subprograms. Signed-off-by:
Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by:
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Alexei Starovoitov authored
LD_[ABS|IND] instructions may return from the function early. bpf_tail_call pseudo instruction is either fallthrough or return. Allow them in the subprograms only when subprograms are BTF annotated and have scalar return types. Allow ld_abs and tail_call in the main program even if it calls into subprograms. In the past that was not ok to do for ld_abs, since it was JITed with special exit sequence. Since bpf_gen_ld_abs() was introduced the ld_abs looks like normal exit insn from JIT point of view, so it's safe to allow them in the main program. Signed-off-by: -
Maciej Fijalkowski authored
Relax verifier's restriction that was meant to forbid tailcall usage when subprog count was higher than 1. Also, do not max out the stack depth of program that utilizes tailcalls. Signed-off-by:
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Maciej Fijalkowski authored
This commit serves two things: 1) it optimizes BPF prologue/epilogue generation 2) it makes possible to have tailcalls within BPF subprogram Both points are related to each other since without 1), 2) could not be achieved. In [1], Alexei says: "The prologue will look like: nop5 xor eax,eax // two new bytes if bpf_tail_call() is used in this // function push rbp mov rbp, rsp sub rsp, rounded_stack_depth push rax // zero init tail_call counter variable number of push rbx,r13,r14,r15 Then bpf_tail_call will pop variable number rbx,.. and final 'pop rax' Then 'add rsp, size_of_current_stack_frame' jmp to next function and skip over 'nop5; xor eax,eax; push rpb; mov rbp, rsp' This way new function will set its own stack size and will init tail call counter with whatever value the parent had. If next function doesn't use bpf_tail_call it won't have 'xor eax,eax'. Instead it would need to have 'nop2' in there." Implement that suggestion. Since the layout of stack is changed, tail call counter handling can not rely anymore on popping it to rbx just like it have been handled for constant prologue case and later overwrite of rbx with actual value of rbx pushed to stack. Therefore, let's use one of the register (%rcx) that is considered to be volatile/caller-saved and pop the value of tail call counter in there in the epilogue. Drop the BUILD_BUG_ON in emit_prologue and in emit_bpf_tail_call_indirect where instruction layout is not constant anymore. Introduce new poke target, 'tailcall_bypass' to poke descriptor that is dedicated for skipping the register pops and stack unwind that are generated right before the actual jump to target program. For case when the target program is not present, BPF program will skip the pop instructions and nop5 dedicated for jmpq $target. An example of such state when only R6 of callee saved registers is used by program: ffffffffc0513aa1: e9 0e 00 00 00 jmpq 0xffffffffc0513ab4 ffffffffc0513aa6: 5b pop %rbx ffffffffc0513aa7: 58 pop %rax ffffffffc0513aa8: 48 81 c4 00 00 00 00 add $0x0,%rsp ffffffffc0513aaf: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) ffffffffc0513ab4: 48 89 df mov %rbx,%rdi When target program is inserted, the jump that was there to skip pops/nop5 will become the nop5, so CPU will go over pops and do the actual tailcall. One might ask why there simply can not be pushes after the nop5? In the following example snippet: ffffffffc037030c: 48 89 fb mov %rdi,%rbx (...) ffffffffc0370332: 5b pop %rbx ffffffffc0370333: 58 pop %rax ffffffffc0370334: 48 81 c4 00 00 00 00 add $0x0,%rsp ffffffffc037033b: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) ffffffffc0370340: 48 81 ec 00 00 00 00 sub $0x0,%rsp ffffffffc0370347: 50 push %rax ffffffffc0370348: 53 push %rbx ffffffffc0370349: 48 89 df mov %rbx,%rdi ffffffffc037034c: e8 f7 21 00 00 callq 0xffffffffc0372548 There is the bpf2bpf call (at ffffffffc037034c) right after the tailcall and jump target is not present. ctx is in %rbx register and BPF subprogram that we will call into on ffffffffc037034c is relying on it, e.g. it will pick ctx from there. Such code layout is therefore broken as we would overwrite the content of %rbx with the value that was pushed on the prologue. That is the reason for the 'bypass' approach. Special care needs to be taken during the install/update/remove of tailcall target. In case when target program is not present, the CPU must not execute the pop instructions that precede the tailcall. To address that, the following states can be defined: A nop, unwind, nop B nop, unwind, tail C skip, unwind, nop D skip, unwind, tail A is forbidden (lead to incorrectness). The state transitions between tailcall install/update/remove will work as follows: First install tail call f: C->D->B(f) * poke the tailcall, after that get rid of the skip Update tail call f to f': B(f)->B(f') * poke the tailcall (poke->tailcall_target) and do NOT touch the poke->tailcall_bypass Remove tail call: B(f')->C(f') * poke->tailcall_bypass is poked back to jump, then we wait the RCU grace period so that other programs will finish its execution and after that we are safe to remove the poke->tailcall_target Install new tail call (f''): C(f')->D(f'')->B(f''). * same as first step This way CPU can never be exposed to "unwind, tail" state. Last but not least, when tailcalls get mixed with bpf2bpf calls, it would be possible to encounter the endless loop due to clearing the tailcall counter if for example we would use the tailcall3-like from BPF selftests program that would be subprogram-based, meaning the tailcall would be present within the BPF subprogram. This test, broken down to particular steps, would do: entry -> set tailcall counter to 0, bump it by 1, tailcall to func0 func0 -> call subprog_tail (we are NOT skipping the first 11 bytes of prologue and this subprogram has a tailcall, therefore we clear the counter...) subprog -> do the same thing as entry and then loop forever. To address this, the idea is to go through the call chain of bpf2bpf progs and look for a tailcall presence throughout whole chain. If we saw a single tail call then each node in this call chain needs to be marked as a subprog that can reach the tailcall. We would later feed the JIT with this info and: - set eax to 0 only when tailcall is reachable and this is the entry prog - if tailcall is reachable but there's no tailcall in insns of currently JITed prog then push rax anyway, so that it will be possible to propagate further down the call chain - finally if tailcall is reachable, then we need to precede the 'call' insn with mov rax, [rbp - (stack_depth + 8)] Tail call related cases from test_verifier kselftest are also working fine. Sample BPF programs that utilize tail calls (sockex3, tracex5) work properly as well. [1]: https://lore.kernel.org/bpf/20200517043227.2gpq22ifoq37ogst@ast-mbp.dhcp.thefacebook.com/Suggested-by: -
Maciej Fijalkowski authored
Protect against potential stack overflow that might happen when bpf2bpf calls get combined with tailcalls. Limit the caller's stack depth for such case down to 256 so that the worst case scenario would result in 8k stack size (32 which is tailcall limit * 256 = 8k). Suggested-by:
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- 17 Sep, 2020 3 commits
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Maciej Fijalkowski authored
Reflect the actual purpose of poke->ip and rename it to poke->tailcall_target so that it will not the be confused with another poke target that will be introduced in next commit. While at it, do the same thing with poke->ip_stable - rename it to poke->tailcall_target_stable. Signed-off-by:
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Maciej Fijalkowski authored
Previously, there was no need for poke descriptors being present in subprogram's bpf_prog_aux struct since tailcalls were simply not allowed in them. Each subprog is JITed independently so in order to enable JITing subprograms that use tailcalls, do the following: - in fixup_bpf_calls() store the index of tailcall insn onto the generated poke descriptor, - in case when insn patching occurs, adjust the tailcall insn idx from bpf_patch_insn_data, - then in jit_subprogs() check whether the given poke descriptor belongs to the current subprog by checking if that previously stored absolute index of tail call insn is in the scope of the insns of given subprog, - update the insn->imm with new poke descriptor slot so that while JITing the proper poke descriptor will be grabbed This way each of the main program's poke descriptors are distributed across the subprograms poke descriptor array, so main program's descriptors can be untracked out of the prog array map. Add also subprog's aux struct to the BPF map poke_progs list by calling on it map_poke_track(). In case of any error, call the map_poke_untrack() on subprog's aux structs that have already been registered to prog array map. Signed-off-by:
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Maciej Fijalkowski authored
Currently, %rax is used to store the jump target when BPF program is emitting the retpoline instructions that are handling the indirect tailcall. There is a plan to use %rax for different purpose, which is storing the tail call counter. In order to preserve this value across the tailcalls, adjust the BPF indirect tailcalls so that the target program will reside in %rcx and teach the retpoline instructions about new location of jump target. Signed-off-by:
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- 16 Sep, 2020 7 commits
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Andrii Nakryiko authored
Merge 183 tests from test_btf into test_progs framework to be exercised regularly. All the test_btf tests that were moved are modeled as proper sub-tests in test_progs framework for ease of debugging and reporting. No functional or behavioral changes were intended, I tried to preserve original behavior as much as possible. E.g., `test_progs -v` will activate "always_log" flag to emit BTF validation log. The only difference is in reducing the max_entries limit for pretty-printing tests from (128 * 1024) to just 128 to reduce tests running time without reducing the coverage. Example test run: $ sudo ./test_progs -n 8 ... #8 btf:OK Summary: 1/183 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by:
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Alexei Starovoitov authored
Stanislav Fomichev says: ==================== Currently, if a user wants to store arbitrary metadata for an eBPF program, for example, the program build commit hash or version, they could store it in a map, and conveniently libbpf uses .data section to populate an internal map. However, if the program does not actually reference the map, then the map would be de-refcounted and freed. This patch set introduces a new syscall BPF_PROG_BIND_MAP to add a map to a program's used_maps, even if the program instructions does not reference the map. libbpf is extended to always BPF_PROG_BIND_MAP .rodata section so the metadata is kept in place. bpftool is also extended to print metadata in the 'bpftool prog' list. The variable is considered metadata if it starts with the magic 'bpf_metadata_' prefix; everything after the prefix is the metadata name. An example use of this would be BPF C file declaring: volatile const char bpf_metadata_commit_hash[] SEC(".rodata") = "abcdef123456"; and bpftool would emit: $ bpftool prog [...] metadata: commit_hash = "abcdef123456" v6 changes: * libbpf: drop FEAT_GLOBAL_DATA from probe_prog_bind_map (Andrii Nakryiko) * bpftool: combine find_metadata_map_id & find_metadata; drops extra bpf_map_get_fd_by_id and bpf_map_get_fd_by_id (Andrii Nakryiko) * bpftool: use strncmp instead of strstr (Andrii Nakryiko) * bpftool: memset(map_info) and extra empty line (Andrii Nakryiko) v5 changes: * selftest: verify that prog holds rodata (Andrii Nakryiko) * selftest: use volatile for metadata (Andrii Nakryiko) * bpftool: use sizeof in BPF_METADATA_PREFIX_LEN (Andrii Nakryiko) * bpftool: new find_metadata that does map lookup (Andrii Nakryiko) * libbpf: don't generalize probe_create_global_data (Andrii Nakryiko) * libbpf: use OPTS_VALID in bpf_prog_bind_map (Andrii Nakryiko) * libbpf: keep LIBBPF_0.2.0 sorted (Andrii Nakryiko) v4 changes: * Don't return EEXIST from syscall if already bound (Andrii Nakryiko) * Removed --metadata argument (Andrii Nakryiko) * Removed custom .metadata section (Alexei Starovoitov) * Addressed Andrii's suggestions about btf helpers and vsi (Andrii Nakryiko) * Moved bpf_prog_find_metadata into bpftool (Alexei Starovoitov) v3 changes: * API changes for bpf_prog_find_metadata (Toke Høiland-Jørgensen) v2 changes: * Made struct bpf_prog_bind_opts in libbpf so flags is optional. * Deduped probe_kern_global_data and probe_prog_bind_map into a common helper. * Added comment regarding why EEXIST is ignored in libbpf bind map. * Froze all LIBBPF_MAP_METADATA internal maps. * Moved bpf_prog_bind_map into new LIBBPF_0.1.1 in libbpf.map. * Added p_err() calls on error cases in bpftool show_prog_metadata. * Reverse christmas tree coding style in bpftool show_prog_metadata. * Made bpftool gen skeleton recognize .metadata as an internal map and generate datasec definition in skeleton. * Added C test using skeleton to see asset that the metadata is what we expect and rebinding causes EEXIST. v1 changes: * Fixed a few missing unlocks, and missing close while iterating map fds. * Move mutex initialization to right after prog aux allocation, and mutex destroy to right after prog aux free. * s/ADD_MAP/BIND_MAP/ * Use mutex only instead of RCU to protect the used_map array & count. Cc: YiFei Zhu <zhuyifei1999@gmail.com> ==================== Acked-by: -
YiFei Zhu authored
This is a simple test to check that loading and dumping metadata in btftool works, whether or not metadata contents are used by the program. A C test is also added to make sure the skeleton code can read the metadata values. Signed-off-by:
YiFei Zhu <zhuyifei@google.com> Signed-off-by:
Stanislav Fomichev <sdf@google.com> Signed-off-by:
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YiFei Zhu authored
Dump metadata in the 'bpftool prog' list if it's present. For some formatting some BTF code is put directly in the metadata dumping. Sanity checks on the map and the kind of the btf_type to make sure we are actually dumping what we are expecting. A helper jsonw_reset is added to json writer so we can reuse the same json writer without having extraneous commas. Sample output: $ bpftool prog 6: cgroup_skb name prog tag bcf7977d3b93787c gpl [...] btf_id 4 metadata: a = "foo" b = 1 $ bpftool prog --json --pretty [{ "id": 6, [...] "btf_id": 4, "metadata": { "a": "foo", "b": 1 } } ] Signed-off-by: -
YiFei Zhu authored
The patch adds a simple wrapper bpf_prog_bind_map around the syscall. When the libbpf tries to load a program, it will probe the kernel for the support of this syscall and unconditionally bind .rodata section to the program. Signed-off-by:
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YiFei Zhu authored
This syscall binds a map to a program. Returns success if the map is already bound to the program. Signed-off-by:
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YiFei Zhu authored
To support modifying the used_maps array, we use a mutex to protect the use of the counter and the array. The mutex is initialized right after the prog aux is allocated, and destroyed right before prog aux is freed. This way we guarantee it's initialized for both cBPF and eBPF. Signed-off-by:
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- 15 Sep, 2020 7 commits
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Yonghong Song authored
When syncing latest libbpf repo to bcc, ubuntu 16.04 (4.4.0 LTS kernel) failed compilation for xsk.c: In file included from /tmp/debuild.0jkauG/bcc/src/cc/libbpf/src/xsk.c:23:0: /tmp/debuild.0jkauG/bcc/src/cc/libbpf/src/xsk.c: In function ‘xsk_get_ctx’: /tmp/debuild.0jkauG/bcc/src/cc/libbpf/include/linux/list.h:81:9: warning: implicit declaration of function ‘container_of’ [-Wimplicit-function-declaration] container_of(ptr, type, member) ^ /tmp/debuild.0jkauG/bcc/src/cc/libbpf/include/linux/list.h:83:9: note: in expansion of macro ‘list_entry’ list_entry((ptr)->next, type, member) ... src/cc/CMakeFiles/bpf-static.dir/build.make:209: recipe for target 'src/cc/CMakeFiles/bpf-static.dir/libbpf/src/xsk.c.o' failed Commit 2f6324a3 ("libbpf: Support shared umems between queues and devices") added include file <linux/list.h>, which uses macro "container_of". xsk.c file also includes <linux/ethtool.h> before <linux/list.h>. In a more recent distro kernel, <linux/ethtool.h> includes <linux/kernel.h> which contains the macro definition for "container_of". So compilation is all fine. But in ubuntu 16.04 kernel, <linux/ethtool.h> does not contain <linux/kernel.h> which caused the above compilation error. Let explicitly add <linux/kernel.h> in xsk.c to avoid compilation error in old distro's. Fixes: 2f6324a3 ("libbpf: Support shared umems between queues and devices") Signed-off-by:Yonghong Song <yhs@fb.com> Signed-off-by:
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Yonghong Song authored
When building bpf selftests like make -C tools/testing/selftests/bpf -j20 I hit the following errors: ... GEN /net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-gen.8 <stdin>:75: (WARNING/2) Block quote ends without a blank line; unexpected unindent. <stdin>:71: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:85: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:57: (WARNING/2) Block quote ends without a blank line; unexpected unindent. <stdin>:66: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:109: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:175: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:273: (WARNING/2) Literal block ends without a blank line; unexpected unindent. make[1]: *** [/net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-perf.8] Error 12 make[1]: *** Waiting for unfinished jobs.... make[1]: *** [/net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-iter.8] Error 12 make[1]: *** [/net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-struct_ops.8] Error 12 ... I am using: -bash-4.4$ rst2man --version rst2man (Docutils 0.11 [repository], Python 2.7.5, on linux2) -bash-4.4$ The Makefile generated final .rst file (e.g., bpftool-cgroup.rst) looks like ... ID AttachType AttachFlags Name \n SEE ALSO\n========\n\t**bpf**\ (2),\n\t**bpf-helpers**\ (7),\n\t**bpftool**\ (8),\n\t**bpftool-btf**\ (8),\n\t**bpftool-feature**\ (8),\n\t**bpftool-gen**\ (8),\n\t**bpftool-iter**\ (8),\n\t**bpftool-link**\ (8),\n\t**bpftool-map**\ (8),\n\t**bpftool-net**\ (8),\n\t**bpftool-perf**\ (8),\n\t**bpftool-prog**\ (8),\n\t**bpftool-struct_ops**\ (8)\n The rst2man generated .8 file looks like Literal block ends without a blank line; unexpected unindent. .sp n SEEALSOn========nt**bpf**(2),nt**bpf\-helpers**(7),nt**bpftool**(8),nt**bpftool\-btf**(8),nt** bpftool\-feature**(8),nt**bpftool\-gen**(8),nt**bpftool\-iter**(8),nt**bpftool\-link**(8),nt** bpftool\-map**(8),nt**bpftool\-net**(8),nt**bpftool\-perf**(8),nt**bpftool\-prog**(8),nt** bpftool\-struct_ops**(8)n Looks like that particular version of rst2man prefers to have actual new line instead of \n. Since `echo -e` may not be available in some environment, let us use `printf`. Format string "%b" is used for `printf` to ensure all escape characters are interpretted properly. Fixes: 18841da9 ("tools: bpftool: Automate generation for "SEE ALSO" sections in man pages") Suggested-by:Andrii Nakryiko <andrii.nakryiko@gmail.com> Signed-off-by:
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Magnus Karlsson authored
Fix a potential refcount warning that a zero value is increased to one in xp_dma_map, by initializing the refcount to one to start with, instead of zero plus a refcount_inc(). Fixes: 921b6869 ("xsk: Enable sharing of dma mappings") Signed-off-by:
Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by:
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Magnus Karlsson authored
Add a quiet option (-Q) that disables the statistics print outs of xdpsock. This is good to have when measuring 0% loss rate performance as it will be quite terrible if the application uses printfs. Signed-off-by:
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Magnus Karlsson authored
Fix a possible deadlock in the l2fwd application in xdpsock that can occur when there is no space in the Tx ring. There are two ways to get the kernel to consume entries in the Tx ring: calling sendto() to make it send packets and freeing entries from the completion ring, as the kernel will not send a packet if there is no space for it to add a completion entry in the completion ring. The Tx loop in l2fwd only used to call sendto(). This patches adds cleaning the completion ring in that loop. Signed-off-by:
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Magnus Karlsson authored
Fix the sending of a single packet (or small burst) in xdpsock when executing in copy mode. Currently, the l2fwd application in xdpsock only transmits the packets after a batch of them has been received, which might be confusing if you only send one packet and expect that it is returned pronto. Fix this by calling sendto() more often and add a comment in the code that states that this can be optimized if needed. Reported-by:
Tirthendu Sarkar <tirthendu.sarkar@intel.com> Signed-off-by:
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Ilya Leoshkevich authored
In order to branch around tail calls (due to out-of-bounds index, exceeding tail call count or missing tail call target), JIT uses label[0] field, which contains the address of the instruction following the tail call. When there are multiple tail calls, label[0] value comes from handling of a previous tail call, which is incorrect. Fix by getting rid of label array and resolving the label address locally: for all 3 branches that jump to it, emit 0 offsets at the beginning, and then backpatch them with the correct value. Also, do not use the long jump infrastructure: the tail call sequence is known to be short, so make all 3 jumps short. Fixes: 6651ee07 ("s390/bpf: implement bpf_tail_call() helper") Signed-off-by:
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- 11 Sep, 2020 6 commits
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Alexei Starovoitov authored
Neal Cardwell says: ==================== This patch series reorganizes TCP congestion control initialization so that if EBPF code called by tcp_init_transfer() sets the congestion control algorithm by calling setsockopt(TCP_CONGESTION) then the TCP stack initializes the congestion control module immediately, instead of having tcp_init_transfer() later initialize the congestion control module. This increases flexibility for the EBPF code that runs at connection establishment time, and simplifies the code. This has the following benefits: (1) This allows CC module customizations made by the EBPF called in tcp_init_transfer() to persist, and not be wiped out by a later call to tcp_init_congestion_control() in tcp_init_transfer(). (2) Does not flip the order of EBPF and CC init, to avoid causing bugs for existing code upstream that depends on the current order. (3) Does not cause 2 initializations for for CC in the case where the EBPF called in tcp_init_transfer() wants to set the CC to a new CC algorithm. (4) Allows follow-on simplifications to the code in net/core/filter.c and net/ipv4/tcp_cong.c, which currently both have some complexity to special-case CC initialization to avoid double CC initialization if EBPF sets the CC. changes in v2: o rebase onto bpf-next o add another follow-on simplification suggested by Martin KaFai Lau: "tcp: simplify tcp_set_congestion_control() load=false case" changes in v3: o no change in commits o resent patch series from @gmail.com, since mail from ncardwell@google.com stopped being accepted at netdev@vger.kernel.org mid-way through processing the v2 patch series (between patches 2 and 3), confusing patchwork about which patches belonged to the v2 patch series ==================== Acked-by: -
Neal Cardwell authored
Simplify tcp_set_congestion_control() by removing the initialization code path for the !load case. There are only two call sites for tcp_set_congestion_control(). The EBPF call site is the only one that passes load=false; it also passes cap_net_admin=true. Because of that, the exact same behavior can be achieved by removing the special if (!load) branch of the logic. Both before and after this commit, the EBPF case will call bpf_try_module_get(), and if that succeeds then call tcp_reinit_congestion_control() or if that fails then return EBUSY. Note that this returns the logic to a structure very similar to the structure before: commit 91b5b21c ("bpf: Add support for changing congestion control") except that the CAP_NET_ADMIN status is passed in as a function argument. This clean-up was suggested by Martin KaFai Lau. Suggested-by:
Neal Cardwell <ncardwell@google.com> Signed-off-by:
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Neal Cardwell authored
Now that the previous patches have removed the code that uses the flags argument to _bpf_setsockopt(), we can remove that argument. Signed-off-by:
Eric Dumazet <edumazet@google.com> Signed-off-by:
Yuchung Cheng <ycheng@google.com> Acked-by:
Kevin Yang <yyd@google.com> Cc: Lawrence Brakmo <brakmo@fb.com>
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Neal Cardwell authored
Now that the previous patches ensure that all call sites for tcp_set_congestion_control() want to initialize congestion control, we can simplify tcp_set_congestion_control() by removing the reinit argument and the code to support it. Signed-off-by:
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Neal Cardwell authored
Now that the previous patch ensures we don't initialize the congestion control twice, when EBPF sets the congestion control algorithm at connection establishment we can simplify the code by simply initializing the congestion control module at that time. Signed-off-by:
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Neal Cardwell authored
Change tcp_init_transfer() to only initialize congestion control if it has not been initialized already. With this new approach, we can arrange things so that if the EBPF code sets the congestion control by calling setsockopt(TCP_CONGESTION) then tcp_init_transfer() will not re-initialize the CC module. This is an approach that has the following beneficial properties: (1) This allows CC module customizations made by the EBPF called in tcp_init_transfer() to persist, and not be wiped out by a later call to tcp_init_congestion_control() in tcp_init_transfer(). (2) Does not flip the order of EBPF and CC init, to avoid causing bugs for existing code upstream that depends on the current order. (3) Does not cause 2 initializations for for CC in the case where the EBPF called in tcp_init_transfer() wants to set the CC to a new CC algorithm. (4) Allows follow-on simplifications to the code in net/core/filter.c and net/ipv4/tcp_cong.c, which currently both have some complexity to special-case CC initialization to avoid double CC initialization if EBPF sets the CC. Signed-off-by:
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