- 30 Jan, 2023 6 commits
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Ilya Leoshkevich authored
Implement calling kernel functions from eBPF. In general, the eBPF ABI is fairly close to that of s390x, with one important difference: on s390x callers should sign-extend signed arguments. Handle that by using information returned by bpf_jit_find_kfunc_model(). Here is an example of how sign extensions works. Suppose we need to call the following function from BPF: ; long noinline bpf_kfunc_call_test4(signed char a, short b, int c, long d) 0000000000936a78 <bpf_kfunc_call_test4>: 936a78: c0 04 00 00 00 00 jgnop bpf_kfunc_call_test4 ; return (long)a + (long)b + (long)c + d; 936a7e: b9 08 00 45 agr %r4,%r5 936a82: b9 08 00 43 agr %r4,%r3 936a86: b9 08 00 24 agr %r2,%r4 936a8a: c0 f4 00 1e 3b 27 jg <__s390_indirect_jump_r14> As per the s390x ABI, bpf_kfunc_call_test4() has the right to assume that a, b and c are sign-extended by the caller, which results in using 64-bit additions (agr) without any additional conversions. Without sign extension we would have the following on the JITed code side: ; tmp = bpf_kfunc_call_test4(-3, -30, -200, -1000); ; 5: b4 10 00 00 ff ff ff fd w1 = -3 0x3ff7fdcdad4: llilf %r2,0xfffffffd ; 6: b4 20 00 00 ff ff ff e2 w2 = -30 0x3ff7fdcdada: llilf %r3,0xffffffe2 ; 7: b4 30 00 00 ff ff ff 38 w3 = -200 0x3ff7fdcdae0: llilf %r4,0xffffff38 ; 8: b7 40 00 00 ff ff fc 18 r4 = -1000 0x3ff7fdcdae6: lgfi %r5,-1000 0x3ff7fdcdaec: mvc 64(4,%r15),160(%r15) 0x3ff7fdcdaf2: lgrl %r1,bpf_kfunc_call_test4@GOT 0x3ff7fdcdaf8: brasl %r14,__s390_indirect_jump_r1 This first 3 llilfs are 32-bit loads, that need to be sign-extended to 64 bits. Note: at the moment bpf_jit_find_kfunc_model() does not seem to play nicely with XDP metadata functions: add_kfunc_call() adds an "abstract" bpf_*() version to kfunc_btf_tab, but then fixup_kfunc_call() puts the concrete version into insn->imm, which bpf_jit_find_kfunc_model() cannot find. But this seems to be a common code problem. Signed-off-by:Ilya Leoshkevich <iii@linux.ibm.com> Link: https://lore.kernel.org/r/20230129190501.1624747-7-iii@linux.ibm.comSigned-off-by:
Alexei Starovoitov <ast@kernel.org>
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Ilya Leoshkevich authored
Allow mixing subprogs and tail calls by passing the current tail call count to subprogs. Signed-off-by:
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Ilya Leoshkevich authored
arch_prepare_bpf_trampoline() is used for direct attachment of eBPF programs to various places, bypassing kprobes. It's responsible for calling a number of eBPF programs before, instead and/or after whatever they are attached to. Add a s390x implementation, paying attention to the following: - Reuse the existing JIT infrastructure, where possible. - Like the existing JIT, prefer making multiple passes instead of backpatching. Currently 2 passes is enough. If literal pool is introduced, this needs to be raised to 3. However, at the moment adding literal pool only makes the code larger. If branch shortening is introduced, the number of passes needs to be increased even further. - Support both regular and ftrace calling conventions, depending on the trampoline flags. - Use expolines for indirect calls. - Handle the mismatch between the eBPF and the s390x ABIs. - Sign-extend fmod_ret return values. invoke_bpf_prog() produces about 120 bytes; it might be possible to slightly optimize this, but reaching 50 bytes, like on x86_64, looks unrealistic: just loading cookie, __bpf_prog_enter, bpf_func, insnsi and __bpf_prog_exit as literals already takes at least 5 * 12 = 60 bytes, and we can't use relative addressing for most of them. Therefore, lower BPF_MAX_TRAMP_LINKS on s390x. Signed-off-by:
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Ilya Leoshkevich authored
bpf_arch_text_poke() is used to hotpatch eBPF programs and trampolines. s390x has a very strict hotpatching restriction: the only thing that is allowed to be hotpatched is conditional branch mask. Take the same approach as commit de5012b4 ("s390/ftrace: implement hotpatching"): create a conditional jump to a "plt", which loads the target address from memory and jumps to it; then first patch this address, and then the mask. Trampolines (introduced in the next patch) respect the ftrace calling convention: the return address is in %r0, and %r1 is clobbered. With that in mind, bpf_arch_text_poke() does not differentiate between jumps and calls. However, there is a simple optimization for jumps (for the epilogue_ip case): if a jump already points to the destination, then there is no "plt" and we can just flip the mask. For simplicity, the "plt" template is defined in assembly, and its size is used to define C arrays. There doesn't seem to be a way to convey this size to C as a constant, so it's hardcoded and double-checked during runtime. Signed-off-by:
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Ilya Leoshkevich authored
All the indirect jumps in the eBPF JIT already use expolines, except for the tail call one. Fixes: de5cb6eb ("s390: use expoline thunks in the BPF JIT") Signed-off-by:
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Ilya Leoshkevich authored
sk_assign is failing on an s390x machine running Debian "bookworm" for 2 reasons: legacy server_map definition and uninitialized addrlen in recvfrom() call. Fix by adding a new-style server_map definition and dropping addrlen (recvfrom() allows NULL values for src_addr and addrlen). Since the test should support tc built without libbpf, build the prog twice: with the old-style definition and with the new-style definition, then select the right one at runtime. This could be done at compile time too, but this would not be cross-compilation friendly. Signed-off-by:
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- 28 Jan, 2023 34 commits
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Ilya Leoshkevich authored
"desription" should be "description". Signed-off-by:
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Ilya Leoshkevich authored
s390x eBPF JIT needs to know whether a function return value is signed and which function arguments are signed, in order to generate code compliant with the s390x ABI. Signed-off-by:
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Ilya Leoshkevich authored
iterators.lskel.h is little-endian, therefore bpf iterator is currently broken on big-endian systems. Introduce a big-endian version and add instructions regarding its generation. Unfortunately bpftool's cross-endianness capabilities are limited to BTF right now, so the procedure requires access to a big-endian machine or a configured emulator. Signed-off-by:
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Ilya Leoshkevich authored
BPF_PROBE_READ_INTO() and BPF_PROBE_READ_STR_INTO() should map to bpf_probe_read() and bpf_probe_read_str() respectively in order to work correctly on architectures with !ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE. Signed-off-by:
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Ilya Leoshkevich authored
Loading programs that use bpf_usdt_arg() on s390x fails with: ; if (arg_num >= BPF_USDT_MAX_ARG_CNT || arg_num >= spec->arg_cnt) 128: (79) r1 = *(u64 *)(r10 -24) ; frame1: R1_w=scalar(umax=4294967295,var_off=(0x0; 0xffffffff)) R10=fp0 129: (25) if r1 > 0xb goto pc+83 ; frame1: R1_w=scalar(umax=11,var_off=(0x0; 0xf)) ... ; arg_spec = &spec->args[arg_num]; 135: (79) r1 = *(u64 *)(r10 -24) ; frame1: R1_w=scalar(umax=4294967295,var_off=(0x0; 0xffffffff)) R10=fp0 ... ; switch (arg_spec->arg_type) { 139: (61) r1 = *(u32 *)(r2 +8) R2 unbounded memory access, make sure to bounds check any such access The reason is that, even though the C code enforces that arg_num < BPF_USDT_MAX_ARG_CNT, the verifier cannot propagate this constraint to the arg_spec assignment yet. Help it by forcing r1 back to stack after comparison. Signed-off-by: -
Ilya Leoshkevich authored
Use a single "+r" constraint instead of the separate "=r" and "0". Signed-off-by:
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Ilya Leoshkevich authored
Use bpf_probe_read_kernel() and bpf_probe_read_kernel_str() instead of bpf_probe_read() and bpf_probe_read_kernel(). Signed-off-by:
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Ilya Leoshkevich authored
Use the correct datatype for the values map values; currently the test works by accident, since on little-endian machines it is sometimes acceptable to access u64 as u32. Signed-off-by:
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Ilya Leoshkevich authored
Use a syscall macro to access the nanosleep()'s first argument; currently the code uses gprs[2] instead of orig_gpr2. Signed-off-by:
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Ilya Leoshkevich authored
s390x cache line size is 256 bytes, so skb_shared_info must be aligned on a much larger boundary than for x86. Signed-off-by:
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Ilya Leoshkevich authored
Use syscall macros to access the setdomainname() arguments; currently the code uses gprs[2] instead of orig_gpr2 for the first argument. Signed-off-by:
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Ilya Leoshkevich authored
s390x ABI requires the caller to zero- or sign-extend the arguments. eBPF already deals with zero-extension (by definition of its ABI), but not with sign-extension. Add a test to cover that potentially problematic area. Signed-off-by:
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Ilya Leoshkevich authored
sizeof(struct bpf_local_storage_elem) is 512 on s390x: struct bpf_local_storage_elem { struct hlist_node map_node; /* 0 16 */ struct hlist_node snode; /* 16 16 */ struct bpf_local_storage * local_storage; /* 32 8 */ struct callback_head rcu __attribute__((__aligned__(8))); /* 40 16 */ /* XXX 200 bytes hole, try to pack */ /* --- cacheline 1 boundary (256 bytes) --- */ struct bpf_local_storage_data sdata __attribute__((__aligned__(256))); /* 256 8 */ /* size: 512, cachelines: 2, members: 5 */ /* sum members: 64, holes: 1, sum holes: 200 */ /* padding: 248 */ /* forced alignments: 2, forced holes: 1, sum forced holes: 200 */ } __attribute__((__aligned__(256))); As the existing comment suggests, use a larger number in order to be future-proof. Signed-off-by: -
Ilya Leoshkevich authored
If stack_mprotect() succeeds, errno is not changed. This can produce misleading error messages, that show stale errno. Signed-off-by:
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Ilya Leoshkevich authored
Sync the definition of socket_cookie between the eBPF program and the test. Currently the test works by accident, since on little-endian it is sometimes acceptable to access u64 as u32. Signed-off-by:
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Ilya Leoshkevich authored
s390x cache line size is 256 bytes, so skb_shared_info must be aligned on a much larger boundary than for x86. This makes the maximum packet size smaller. Signed-off-by:
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Ilya Leoshkevich authored
Use bpf_probe_read_kernel() instead of bpf_probe_read(), which is not defined on all architectures. While at it, improve the error handling: do not hide the verifier log, and check the return values of bpf_probe_read_kernel() and bpf_copy_from_user(). Signed-off-by:
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Ilya Leoshkevich authored
decap_sanity prints the following on the 1st run: decap_sanity: sh: 1: Syntax error: Bad fd number and the following on the 2nd run: Cannot create namespace file "/run/netns/decap_sanity_ns": File exists The problem is that the cleanup command has a typo and does nothing. Fix the typo. Signed-off-by: -
Ilya Leoshkevich authored
The result of urand_spawn() is checked with ASSERT_OK_PTR, which treats NULL as success if errno == 0. Signed-off-by:
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Ilya Leoshkevich authored
h_proto is big-endian; use htons() in order to make comparison work on both little- and big-endian machines. Signed-off-by:
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Ilya Leoshkevich authored
When building with O=, the following error occurs: ln: failed to create symbolic link 'no_alu32/bpftool': No such file or directory Adjust the code to account for $(OUTPUT). Signed-off-by: -
Ilya Leoshkevich authored
When building with O=, the following linker error occurs: clang: error: no such file or directory: 'liburandom_read.so' Fix by adding $(OUTPUT) to the linker search path. Signed-off-by: -
Ilya Leoshkevich authored
Do not hard-code the value, since for s390x it will be smaller than for x86. Signed-off-by:
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Ilya Leoshkevich authored
This way it's possible to query its value from testcases using BTF. Signed-off-by:
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Ilya Leoshkevich authored
These functions already check that th_len < sizeof(*th), and propagating the lower bound (th_len > 0) may be challenging in complex code, e.g. as is the case with xdp_synproxy test on s390x [1]. Switch to ARG_CONST_SIZE_OR_ZERO in order to make the verifier accept code where it cannot prove that th_len > 0. [1] https://lore.kernel.org/bpf/CAEf4Bzb3uiSHtUbgVWmkWuJ5Sw1UZd4c_iuS4QXtUkXmTTtXuQ@mail.gmail.com/Signed-off-by:
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Randy Dunlap authored
Correct spelling problems for Documentation/bpf/ as reported by codespell. Signed-off-by:
Randy Dunlap <rdunlap@infradead.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: bpf@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-doc@vger.kernel.org Reviewed-by:
Bagas Sanjaya <bagasdotme@gmail.com> Link: https://lore.kernel.org/r/20230128195046.13327-1-rdunlap@infradead.orgSigned-off-by:
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David Vernet authored
The first element of a struct bpf_cpumask is a cpumask_t. This is done to allow struct bpf_cpumask to be cast to a struct cpumask. If this element were ever moved to another field, any BPF program passing a struct bpf_cpumask * to a kfunc expecting a const struct cpumask * would immediately fail to load. Add a build-time assertion so this is assumption is captured and verified. Signed-off-by:
David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230128141537.100777-1-void@manifault.comSigned-off-by:
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Johannes Berg authored
For large ranges (outside of s16) the documentation currently recommends open-coding the validation, but it's better to use the NLA_POLICY_FULL_RANGE() or NLA_POLICY_FULL_RANGE_SIGNED() policy validation instead; recommend that. Signed-off-by:
Johannes Berg <johannes.berg@intel.com> Reviewed-by:
Ido Schimmel <idosch@nvidia.com> Link: https://lore.kernel.org/r/20230127084506.09f280619d64.I5dece85f06efa8ab0f474ca77df9e26d3553d4ab@changeidSigned-off-by:
Jakub Kicinski <kuba@kernel.org>
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https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski authored
Daniel Borkmann says: ==================== bpf-next 2023-01-28 We've added 124 non-merge commits during the last 22 day(s) which contain a total of 124 files changed, 6386 insertions(+), 1827 deletions(-). The main changes are: 1) Implement XDP hints via kfuncs with initial support for RX hash and timestamp metadata kfuncs, from Stanislav Fomichev and Toke Høiland-Jørgensen. Measurements on overhead: https://lore.kernel.org/bpf/875yellcx6.fsf@toke.dk 2) Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case, from Andrii Nakryiko. 3) Significantly reduce the search time for module symbols by livepatch and BPF, from Jiri Olsa and Zhen Lei. 4) Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals, from David Vernet. 5) Fix several issues in the dynptr processing such as stack slot liveness propagation, missing checks for PTR_TO_STACK variable offset, etc, from Kumar Kartikeya Dwivedi. 6) Various performance improvements, fixes, and introduction of more than just one XDP program to XSK selftests, from Magnus Karlsson. 7) Big batch to BPF samples to reduce deprecated functionality, from Daniel T. Lee. 8) Enable struct_ops programs to be sleepable in verifier, from David Vernet. 9) Reduce pr_warn() noise on BTF mismatches when they are expected under the CONFIG_MODULE_ALLOW_BTF_MISMATCH config anyway, from Connor O'Brien. 10) Describe modulo and division by zero behavior of the BPF runtime in BPF's instruction specification document, from Dave Thaler. 11) Several improvements to libbpf API documentation in libbpf.h, from Grant Seltzer. 12) Improve resolve_btfids header dependencies related to subcmd and add proper support for HOSTCC, from Ian Rogers. 13) Add ipip6 and ip6ip decapsulation support for bpf_skb_adjust_room() helper along with BPF selftests, from Ziyang Xuan. 14) Simplify the parsing logic of structure parameters for BPF trampoline in the x86-64 JIT compiler, from Pu Lehui. 15) Get BTF working for kernels with CONFIG_RUST enabled by excluding Rust compilation units with pahole, from Martin Rodriguez Reboredo. 16) Get bpf_setsockopt() working for kTLS on top of TCP sockets, from Kui-Feng Lee. 17) Disable stack protection for BPF objects in bpftool given BPF backends don't support it, from Holger Hoffstätte. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (124 commits) selftest/bpf: Make crashes more debuggable in test_progs libbpf: Add documentation to map pinning API functions libbpf: Fix malformed documentation formatting selftests/bpf: Properly enable hwtstamp in xdp_hw_metadata selftests/bpf: Calls bpf_setsockopt() on a ktls enabled socket. bpf: Check the protocol of a sock to agree the calls to bpf_setsockopt(). bpf/selftests: Verify struct_ops prog sleepable behavior bpf: Pass const struct bpf_prog * to .check_member libbpf: Support sleepable struct_ops.s section bpf: Allow BPF_PROG_TYPE_STRUCT_OPS programs to be sleepable selftests/bpf: Fix vmtest static compilation error tools/resolve_btfids: Alter how HOSTCC is forced tools/resolve_btfids: Install subcmd headers bpf/docs: Document the nocast aliasing behavior of ___init bpf/docs: Document how nested trusted fields may be defined bpf/docs: Document cpumask kfuncs in a new file selftests/bpf: Add selftest suite for cpumask kfuncs selftests/bpf: Add nested trust selftests suite bpf: Enable cpumasks to be queried and used as kptrs bpf: Disallow NULLable pointers for trusted kfuncs ... ==================== Link: https://lore.kernel.org/r/20230128004827.21371-1-daniel@iogearbox.netSigned-off-by:
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Breno Leitao authored
This patch removes the msleep(4s) during netpoll_setup() if the carrier appears instantly. Here are some scenarios where this workaround is counter-productive in modern ages: Servers which have BMC communicating over NC-SI via the same NIC as gets used for netconsole. BMC will keep the PHY up, hence the carrier appearing instantly. The link is fibre, SERDES getting sync could happen within 0.1Hz, and the carrier also appears instantly. Other than that, if a driver is reporting instant carrier and then losing it, this is probably a driver bug. Reported-by:
Michael van der Westhuizen <rmikey@meta.com> Signed-off-by:
Breno Leitao <leitao@debian.org> Link: https://lore.kernel.org/r/20230125185230.3574681-1-leitao@debian.orgSigned-off-by:
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git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski authored
Conflicts: drivers/net/ethernet/intel/ice/ice_main.c 418e5340 ("ice: move devlink port creation/deletion") 643ef23b ("ice: Introduce local var for readability") https://lore.kernel.org/all/20230127124025.0dacef40@canb.auug.org.au/ https://lore.kernel.org/all/20230124005714.3996270-1-anthony.l.nguyen@intel.com/ drivers/net/ethernet/engleder/tsnep_main.c 3d53aaef ("tsnep: Fix TX queue stop/wake for multiple queues") 25faa6a4 ("tsnep: Replace TX spin_lock with __netif_tx_lock") https://lore.kernel.org/all/20230127123604.36bb3e99@canb.auug.org.au/ net/netfilter/nf_conntrack_proto_sctp.c 13bd9b31 ("Revert "netfilter: conntrack: add sctp DATA_SENT state"") a44b7651 ("netfilter: conntrack: unify established states for SCTP paths") f71cb8f4 ("netfilter: conntrack: sctp: use nf log infrastructure for invalid packets") https://lore.kernel.org/all/20230127125052.674281f9@canb.auug.org.au/ https://lore.kernel.org/all/d36076f3-6add-a442-6d4b-ead9f7ffff86@tessares.net/Signed-off-by:
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Arınç ÜNAL authored
Fix description for tristate and help sections which include inaccurate information. Signed-off-by:
Arınç ÜNAL <arinc.unal@arinc9.com> Link: https://lore.kernel.org/r/20230126190110.9124-1-arinc.unal@arinc9.comSigned-off-by:
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Jakub Kicinski authored
Magnus Karlsson says: ==================== net: xdp: execute xdp_do_flush() before napi_complete_done() Make sure that xdp_do_flush() is always executed before napi_complete_done(). This is important for two reasons. First, a redirect to an XSKMAP assumes that a call to xdp_do_redirect() from napi context X on CPU Y will be followed by a xdp_do_flush() from the same napi context and CPU. This is not guaranteed if the napi_complete_done() is executed before xdp_do_flush(), as it tells the napi logic that it is fine to schedule napi context X on another CPU. Details from a production system triggering this bug using the veth driver can be found in [1]. The second reason is that the XDP_REDIRECT logic in itself relies on being inside a single NAPI instance through to the xdp_do_flush() call for RCU protection of all in-kernel data structures. Details can be found in [2]. The drivers have only been compile-tested since I do not own any of the HW below. So if you are a maintainer, it would be great if you could take a quick look to make sure I did not mess something up. Note that these were the drivers I found that violated the ordering by running a simple script and manually checking the ones that came up as potential offenders. But the script was not perfect in any way. There might still be offenders out there, since the script can generate false negatives. [1] https://lore.kernel.org/r/20221220185903.1105011-1-sbohrer@cloudflare.com [2] https://lore.kernel.org/all/20210624160609.292325-1-toke@redhat.com/ ==================== Link: https://lore.kernel.org/r/20230125074901.2737-1-magnus.karlsson@gmail.comSigned-off-by:
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Magnus Karlsson authored
Make sure that xdp_do_flush() is always executed before napi_complete_done(). This is important for two reasons. First, a redirect to an XSKMAP assumes that a call to xdp_do_redirect() from napi context X on CPU Y will be followed by a xdp_do_flush() from the same napi context and CPU. This is not guaranteed if the napi_complete_done() is executed before xdp_do_flush(), as it tells the napi logic that it is fine to schedule napi context X on another CPU. Details from a production system triggering this bug using the veth driver can be found following the first link below. The second reason is that the XDP_REDIRECT logic in itself relies on being inside a single NAPI instance through to the xdp_do_flush() call for RCU protection of all in-kernel data structures. Details can be found in the second link below. Fixes: d678be1d ("dpaa2-eth: add XDP_REDIRECT support") Signed-off-by:
Magnus Karlsson <magnus.karlsson@intel.com> Acked-by:
Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/r/20221220185903.1105011-1-sbohrer@cloudflare.com Link: https://lore.kernel.org/all/20210624160609.292325-1-toke@redhat.com/Signed-off-by:
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